Archive of Our Own ^beta

Chapter Text

It was a hot summer night. The door was open.

Someone, something came inside.

How did this happen? His chest hurt. Gashes raked across his skin, bleeding and bleeding. He placed a hand over his chest, and when he pulled away, the palm was stained red.

The house was empty except for him. He could hear sounds outside; screams of rage, the ripping and tearing of flesh. At some point the sounds stopped, and he was left in silence.

He couldn’t move. His chest hurt. Where was his brother? Was he okay?

He didn’t know how long he laid there, until he heard a new sound. A long scream of pain, pure and primal. The voice of his brother.

“Muichiro!”

He pushed himself to move. Even after the screaming stopped, he kept trying. He feared the worst, but he couldn’t give up.

By some miracle, he found the strength he needed. It was slow and painful; his body screamed in protest. But he moved.

Outside, it was dark but for the light of the moon. He staggered forward, eyes searching for his brother. He spotted something up ahead, a shape framed in moonlight, crouched over the ground. He heard growls like an animal, sounds like ripping and crunching.

He tripped over his own feet and collapsed.

The shape froze, lifted its head, and turned towards him. The face of his brother glared, slitted eyes wide and wild. Something black hung from his mouth, dripping blood and saliva down his chin and on the ground. A snarl like nothing he ever heard before emanated from his throat.

…Mui…?

His vision went black.

—

Yuichiro woke up to silence and daylight. The sun streamed in through the open doorway. It highlighted the blood splattered about the walls, the floor, even the futon he slept on. He hated it, it was disgusting, but he didn’t have the time or means to try and clean the stains out.

That dream again…?

Taking deep breaths to calm himself, his eyes trailed to a dark corner of the tiny house. Beneath a bloodstained white futon, glowing turquoise eyes peered at him, unblinking and deathly silent. They didn’t move, so Yuichiro turned away. At this point, he wasn’t even surprised to see them anymore. He scratched at the itchy bandages wrapped around his chest, hidden under his yukata, and moved to stand up.

It was a new day, and there was work to be done.

—

The summer afternoon was hot. Insects buzzed as the sun beat down unceasingly, and only the shade of the trees provided any relief. Yuichiro spent hours roaming the territory around his small home, setting and checking traps and foraging for food. He found a share of mushrooms that would do for himself, but what he really needed was meat. Any kind of meat.

Luckily for him, one of the traps near his home yielded a rabbit. Unluckily, the trap hadn’t sprung right, catching the rabbit but not killing it. The small brown animal struggled weakly with its head under the trap. Yuichiro suppressed a feeling of pity as he unsheathed a small knife.

It was better this way, he reasoned; the meat would be fresh.

One cut to the neck later, and Yuichiro was on his way back home. The sun was still high, but he was tired and thirsty, and the sweat dampening his bandages irritated the wounds underneath. He couldn’t keep going; fit as he was, he was only eleven.

His house came into view and Yuichiro all but ran through the door. His gaze went first to that one corner; the glowing turquoise eyes hadn’t moved, hiding beneath the futon just as he’d left them. Sometimes he still thought they might disappear, or this might turn out to be one long dream. But the reality always remained the same.

Yuichiro tried not to let his unease show as he approached. He took the rabbit clutched in his hand and tossed it in front of the eyes, which went wide in response.

“Here Mui, eat this. It’s fresh.”

At his words, the futon shifted, and something slowly crawled out. That something looked almost identical to himself, if it wasn’t for the teal sclera and empty turquoise irises that glowed unnaturally in the dark, or the sharp, curved claws that tipped its fingers.

Or the large fangs that filled its mouth as it suddenly leapt forward and sank its teeth into the dead rabbit’s flesh.

Yuichiro flinched and looked away, trying not to focus too much on the sounds of tearing flesh and crunching bone. This was his brother, Muichiro, he reminded himself. His younger twin. That didn’t change, even after… this.

When the sounds ceased, Yuichiro looked back. Muichiro had his head turned, long hair hiding his face as he licked at his fingers. It was as if he was ashamed of his behavior. Nothing remained of the rabbit except scattered scraps of fur and a puddle of blood.

“…How was it?” Yuichiro asked.

“…” Muichiro was silent for several seconds, then he opened his mouth. He seemed to have trouble speaking around his new fangs. “…Bland. Not filling.”

There was no emotion in his voice, just a simple statement of facts. Yuichiro sighed; he wished he could find something that Muichiro would like. Despite being able to eat raw meat now, he was even more picky than before, refusing anything that wasn’t flesh and blood. Even cooked meat, he had found out, was unappetizing to his twin now.

Muichiro looked back at him, and he sighed again at the blood staining his twin’s face. “Ugh, you’re just as messy as ever! Would it kill you to clean your face?” Even as he chided his brother, Yuichiro was grabbing a cloth and dipping it in a bucket of water. Muichiro held still as he came close and started to clean the blood off.

“S-Sorry…”

“Don’t apologize, just do better.” There was a twinge of guilt as soon as the words left his mouth; that was unnecessarily harsh. He couldn’t blame Muichiro for his current state. After all, if it wasn’t for Muichiro, he wouldn’t even be…

Yuichiro shook his head. He didn’t want to think about that night, but how could he not with the constant reminder of it right in front of him? To think that demons were real after all; that woman hadn't been lying. He wished he hadn’t been injured right at the start; maybe he could have helped, maybe he could have stopped what happened. At the very least, he’d know what happened, instead of having to rely on Muichiro’s hazy recollection of the night’s events.

“Do you remember anything yet?” he ventured to ask. About what happened? About our parents? About us?

Muichiro shook his head. Yuichiro sighed. “It’s okay. It’ll come back to you eventually.”

He hoped that was true.

Once his twin’s face was clean, Yuichiro tossed the rag aside and stood up. He stepped back and sat a short distance away, halfway in the sunlight. Muichiro retreated back into his futon, resembling a scared animal as he looked wide-eyed at the sunbathed ground then back at his brother.

Yuichiro shifted uncomfortably. How should he approach this? “Mui… we need to leave.”

Muichiro blinked slowly. His reaction was hard to gauge; ever since his transformation, he’d become much less expressive. It made Yuichiro’s stomach churn, remembering how emotional, to the point of being annoying, his brother used to be. “Leave… why?”

Yuichiro bit back the urge to give a scathing retort and tried to think of a mature, reasonable way to explain himself again. “We’ve gone over this, Mui. We’re running out of supplies; we should have gone down to sell the wood and restock two days ago.”

Indeed, it had now been four days since that fateful night, and even if Yuichiro was now the only one digging into their food stock, they didn’t have much to begin with. “And… and we need to find help. There has to be someone out there… some people who could-”

“No!” Muichiro suddenly shouted, hiding further in his futon. “No people!”

“Look, Mui, I get that you’re scared you might…” Yuichiro couldn’t bring himself to finish that sentence. He shook his head and continued on a different note. “But we can’t hide in here forever! Do you want to spend the rest of your life cowering in this shack?”

Muichiro was quiet, and a heavy silence filled the air. This shack was their family home, the one their parents had built. They’d spent their entire lives here, a whole eleven years. But their mother and father were long dead, and the two of them were barely hanging on now. It was time to move on.

At least, that’s what Yuichiro told himself, again and again.

Muichiro crept forward, sticking his head out and peering up at Yuichiro’s face. He opened his mouth to say something, when something snapped outside the house. In an instant, he hissed - actually hissed, like a cat! - and retreated back into the futon. Yuichiro cursed as he heard voices outside.

“Damn it! Mui, stay here, and don’t come out no matter what!” Yuichiro doubted he needed to tell his brother that, but better safe than sorry. Muichiro had always been an awful listener, after all. He ran outside and immediately felt a surge of anger at the unfortunately familiar sight of a white-haired woman in a traveling kimono.

“You! We told you not to come back here!” Yuichiro shouted, his hands curling into fists at his sides. “You’re not welcome here!”

As Yuichiro stomped closer, he took notice of a man accompanying the woman. The man’s appearance was striking to say the least, with orange hair that spiked out like flames and a fiery cape over some sort of uniform. Yuichiro’s stomach dropped as he caught sight of the sword sheathed at the man’s side.

The fiery haired man looked over the younger boy, his smile bright enough to eclipse the sun. “Good afternoon! You are the older Tokito, Yuichiro, I presume?”

Yuichiro blinked; the man was practically shouting each word as if he wasn’t just a few feet away. He nodded, but didn’t say anything. “Wonderful! My name is Kyojuro Rengoku, a Hashira of the Demon Slayer Corps! Lady Amane and I ask that you and your brother come with us immediately!”

So direct! “Huh?”

“My apologies, Tokito. Allow us to explain,” Amane bowed her head. “There have been reports of demon sightings in this area. It is not safe for you two to stay here any longer.”

Yuichiro felt a chill run through him, but he rolled his eyes and scoffed. “There you go again, spouting nonsense about demons. Demons aren’t real, and Mui and I are fine! We don’t need your help!”

He hoped his words sounded convincing, hoped his voice and body language didn’t betray his fear.

Kyojuro spoke up next. “Beyond just regular demon sightings, we have also received word of an incredibly powerful demon spotted nearby! It may even be an Upper Moon! Thus it would be highly unsafe for civilians such as yourself to remain here unprotected.”

Yuichiro didn’t know what an Upper Moon was, but the gravity in Kyojuro’s voice was proof enough that it couldn’t be anything good. But… he still couldn’t trust them. They were demon slayers; if they found Muichiro as he was now…

“Tokito, may we come in?” Amane asked, “I’m sure your brother would want to be a part of this conversation as well.”

“Don’t you dare!” Yuichiro immediately yelled. “For your information, Muichiro is sleeping! That idiot had a run in with a boar the other day and got hurt, so he needs to rest!”

“Oh my, how awful,” Amane gasped softly, looking genuinely worried. Though for all Yuichiro knew, it could just be an act.

“Indeed! But all the more reason for you to come with us! Young Muichiro needs a safe place to recover!” Kyojuro shouted.

“Hell no! I’m taking care of him just fine; we don’t need your help!” Yuichiro snapped. His patience was quickly wearing thin with these people. “You’re just trying to take advantage of us! So get the hell out of here already!”

He threw his arm out in his anger, which turned out to be a mistake as the wounds beneath his bandages flared in response. He hissed and bent forward with his hands over his chest, and in an instant Kyojuro was right next to him, inspecting him with concern. Yuichiro would have shoved him away if he wasn’t still in so much pain.

“Tokito, are you-” The demon slayer’s question halted as the sound of something falling and breaking came from the house behind them.

That idiot! Yuichiro turned to go back, but Kyojuro had already rushed past him, so fast that he couldn’t begin to keep up with his movements. Within seconds, the hashira was at the doorway and peering inside.

Yuichiro paled; his heart felt like it might burst out of his chest from how fast it was beating. “H-Hey, get away from there! I told you you can’t come in!”

The younger boy ran up behind Kyojuro as he yelled, who was still silently and intently scanning the interior. The bloodstained, damaged interior. Yuichiro tilted his head to see around him and immediately spotted the broken rice container on the floor, and he probably would have been annoyed if he didn’t have much bigger worries right now. Thankfully, though, Muichiro was nowhere in sight.

“…There, see? There’s nothing,” he growled. “So get-”

Again, Kyojuro moved so fast his eyes couldn’t keep up. One moment he was standing in front of him, and the next he was above the futon shoved in the far corner, sword drawn and his squirming twin brother held in his grasp.

“Mui!”

Kyojuro wasn’t smiling anymore, his gaze hard as he looked between the two boys. “This is your brother?”

“Y-Yeah, that’s Muichiro.” Yuichiro felt himself shaking; his eyes were drawn to the sword held in the slayer’s other hand.

“I see. Very well, I will end this quickly and painlessly so he does not suffer.”

His grip on the sword tightened, and Yuichiro cried out, “Wait! He… he hasn’t hurt anyone! He’s innocent, so don’t you dare hurt him, you hear me?!”

“He has yet to harm a human?” Kyojuro didn’t look convinced, but at least his blade was still for now. Muichiro seemed to realize struggling against the Hashira’s grip was pointless, and so he hung limp with a displeased rumbling in his throat.

Yuichiro hesitated for only a moment, his dream flashing back to him. Muichiro had been eating… something. What was it? It hadn’t looked like an animal. But just as quickly, he pushed the doubt aside. His twin brother, who wanted so much to help others… he refused to believe he would ever hurt another human!

“No, of course not! Mui’s a good kid; he would never hurt anyone!”

“Your belief in your brother is admirable,” Kyojuro now wore a smile, but it was softer, more pitying, like he understood what Yuichiro was going through. It just made his blood boil. “But you understand, don’t you? Your brother has become a demon.”

“Of course I understand that! Do you think I’m stupid?!”

“Not at all, it is only natural to want to protect one’s family,” Kyojuro shook his head. “But demons are driven by their instincts to eat humans. A starving demon will attack even family to satisfy its hunger. No matter how kind or gentle they were as a human, a demon will eventually need to hunt and kill.”

Muichiro shook his head and looked Yuichiro’s way. Yuichiro couldn’t read the emotion in his twin’s eyes, but he knew he was pleading for help. The older boy grit his teeth and took a step forward.

“Shut up! First of all, it’s been four days since Mui turned, and he hasn’t once tried to hurt me!” he snapped. “I’ve been feeding him rabbits and other things I can catch on the mountain. I know he’s still hungry, but even so, he’s never attacked me! He’s different! I don’t why, but he is!”

Kyojuro still wore that infuriating sympathetic smile. “I am sorry. What you say may be true, but your words alone do not ensure he won’t attack a human in the future. As the Flame Hashira of the Demon Slayer Corps, I must do my duty.” He shifted his sword and brought it to Muichiro’s neck. The younger clenched his eyes shut as his brother cried out helplessly.

“Wait, stop! Please, just stop!” What could he do? His words weren’t working, and he couldn’t hope to overpower the slayer. He was going to lose his brother, his last remaining family, and he could do nothing about it!

The blade gleamed as it prepared to cut into Muichiro’s neck.

“Kyojuro, do you remember the Master’s words?”

The Hashira froze. He and Yuichiro turned to see Amane step into the house. Her expression was unchanging as she looked between the twins. “No matter what, they are both to be brought to the Ubuyashiki Estate.”

“Lady Amane, I do not believe-”

“No matter what, Kyojuro. Those were his exact words.” Amane repeated sternly. The Hashira remained frozen for a moment longer, then removed his blade from Muichiro’s throat. His grip on Muichiro’s yukata loosened and as the boy fell to the floor, Yuichiro rushed forward and knelt down to hug him tightly.

“Mui, are you okay?!”

“…Yeah…” Muichiro nodded and buried his head against his brother’s chest. Yuichiro breathed a sigh of relief and looked up as Amane approached.

“Yuichiro, Muichiro, please come with us to the Ubuyashiki Estate. Though the situation is not what we expected, I promise that neither of you will come to any harm there.”

There was no room for refusal in her tone, and as Yuichiro glared back at the bewildered Kyojuro, he knew that they didn’t have a choice anymore. He held Muichiro close and forced the words out.

“Fine, we’ll go with you.”

Chapter Text

“Here, Mui, see if you can fit in here.”

Yuichiro sat back to observe his handiwork. With Kyojuro’s help, they had fashioned together a tightly woven basket using the wood and bamboo stalks scattered around the house. They would need some way for Muichiro to travel during the daytime, and this basket was their best option.

Still, Yuichiro couldn’t help but think the basket looked somewhat small. He and his brother weren’t big by any definition, but he wondered if Muichiro could really fit comfortably inside. He watched as his younger twin stared blankly at the basket for several seconds before crawling inside. It definitely didn’t look comfortable with how scrunched in he was, but somehow, he did fit, and Kyojuro was able to close the lid over him.

“Are you sure you don’t wish for me to carry him, Tokito?” Kyojuro asked, now back to that annoyingly loud and chipper tone of voice. “It would be quite easy for me!”

“Hell no! You were going to cut off his head an hour ago!” Yuichiro snapped. “I’m his brother; I’m carrying him!”

Without waiting for a response, Yuichiro grabbed the straps of the basket and hefted it into the air. Except where he expected the weight of his twin to be, there was next to nothing, and Yuichiro stumbled off-balance. But before he could hit the ground, he felt a pair of calloused hands grab him and hold him up.

Kyojuro grinned down at him. “You should be more careful, Tokito!”

Once the moment of shock passed, Yuichiro felt his face heat up from pure fury. “L-Let go of me, you stupid owl face!”

“You are welcome!”

“I didn’t- agh!” Yuichiro couldn’t tell if he was being messed with or if the slayer was genuinely this dense. He freed himself from Kyojuro’s grasp and looked at Muichiro’s basket in his hand. It still felt like he was holding only the basket with nothing inside.

“Um, Mui, you in there?”

“…Yeah.” His twin’s voice was unmistakable, and he sighed in relief. Still, he remained confused. Was this a demon thing? He’d heard demons could change their forms; could they make themselves lighter, too? He considered asking Kyojuro, then remembered his previous anger and decided not to.

“Are you ready?” Amane asked from near the doorway. “It would be best to leave while we still have hours of daylight remaining.”

Yuichiro’s anger was doused by a sudden somberness. He looked around the house one last time; small and rundown as it was, it was still home. Their parents’ graves were here, and all their memories, too. But just as the nostalgia was starting to get the better of him, Yuichiro remembered himself and shook his head in disgust. He and his brother had nothing to gain from such sentimentality; better to leave now before they made it any harder on themselves.

The boy nodded and slipped the basket onto his back. Though it was still unbelievably light, he could feel his twin’s presence within. It gave him comfort, and the strength of will he needed. “Yeah, let’s go.”

Yuichiro stepped into the sunlight, and for a moment he felt worry, that the basket wasn’t knit tight enough, that the sun would reach his brother. But Muichiro remained calm behind him, and Yuichiro let out a breath he didn’t know he’d been holding.

With Amane and Kyojuro behind him, Yuichiro refused to look back as he and Muichiro left their childhood home for the final time.

—

“How far are we going, anyway?”

Yuichiro wasn’t sure how long they’d been walking. He’d estimated they left in the late afternoon, but now the sun was setting, painting the sky shades of yellow and orange. All he could tell was that they were almost off the mountain. And while there was a village at the base of the mountain, he doubted the Ubuyashiki Estate was there. They were going in the wrong direction for that, anyway.

Exhaustion was slowly but surely creeping up at him as he voiced his question. He was in no way surprised that Kyojuro was still going strong, but he couldn’t fathom how Amane was still walking so gracefully in such fancy clothes. He wished he could at least talk to Muichiro, break up the monotony of travel, but his brother seemed to have fallen asleep or something. Only the feeling of his presence assured him he was still there.

“We won’t be able to reach the estate before nightfall, so we’ll be staying at one of the corps’ rest stops tonight. Don’t worry though, It’s not much farther.” Amane explained.

Yuichiro nodded and kept walking; no use in wasting energy complaining. After about ten more minutes of travel, Amane stopped. “We’re here.”

Yuichiro peered around her, and his eyes widened at the sight of a large wooden building amongst the trees. He had lived on this mountain his whole life, and never once knew this was here. Compared to his own home, it was like a mansion. The image of a wisteria flower adorned the doorway to what he guessed was an inn.

“Quickly now, before night falls!” Kyojuro ushered him in. Yuichiro didn’t need to be told twice, eager to finally rest after such an exhausting day.

The staff were already waiting at the entrance, clearly expecting their arrival. Within minutes, all four of them were settled in a cozy bedroom. Their caretakers closed the sliding door with a click, and once he was sure they were gone, Yuichiro removed the basket from his back and set it on the ground.

“Alright Mui, it’s safe to come out now.”

He started to open the lid as he spoke, but as he did, a tendril of wispy white fog escaped through the gap he’d created. Yuichiro froze, not quite comprehending what he was seeing, and in that time, the misty tendril retreated back into the basket. A second later the lid popped off as Muichiro sprang up with an annoyed grunt.

Yuichiro blinked and decided whatever that was, it wasn’t worth worrying about now. “How are you feeling?”

“…Hungry,” he said bluntly.

Mortified, Yuichiro sprang up and punched his twin in the arm. “Don’t say that in front of the demon slayers, stupid!”

Muichiro didn’t seem bothered by the punch and merely sat down on the floor. He stared silently at Kyojuro, who stared back quizzically. He was still smiling though.

What a weirdo.

“Muichiro does seem quite different from other demons,” Kyojuro observed. “He's quite strange, in fact! Why is that?”

“If I knew that, I’d tell you. He just is.” Yuichiro paused, then added with a glare, "Different, I mean. Not strange."

“Perhaps you’d be willing to tell us what happened the night your brother was turned?” the Hashira suggested. “It may provide us with answers.”

Yuichiro scoffed and sat down next to his twin. “I doubt it, I barely know anything myself. When we were attacked, I got injured and couldn’t move. I think Muichiro fought the demon, but by the time I saw him again, he was already turned. But I'm pretty sure the demon that attacked us and the demon who turned Muichiro aren't the same.”

He didn't mention the dream, nor the mysterious thing he’d seen Muichiro eating before he blacked out. He still vividly remembered waking back up in the house with those glowing eyes peering at him from the darkness. He’s not proud of how loud he had screamed.

“You believe there were two demons there that night?” Kyojuro asked.

Yuichiro nodded and turned to his brother, waiting for him to speak. But Muichiro looked hesitant, so after a moment, he reached over and took his brother’s hand in his own. Empty turquoise eyes widened ever so slightly in response.

“Come on, Mui, tell them what you saw.”

“…Six eyes…” Muichiro fell silent after that. Kyojuro seemed to expect him to elaborate, but when he didn’t, his smile fell.

“Is that all?”

Muichiro nodded, and Kyojuro looked thoughtful. “‘Six eyes’ must refer to the demon. Perhaps it is indeed an Upper Moon?”

“Why do you think that?” Yuichiro couldn’t help but ask. “What is an Upper Moon, anyway?”

“The Upper Moons are the six strongest demons under the command of the demon king, Muzan Kibutsuji. Only Kibutsuji, or the Upper Moons who possess his blood, have the power to turn a human into a demon. This also supports there being two demons, since if an Upper Moon attacked you with the intent to kill, you would not be alive right now. Young Muichiro, was there a number in the demon’s eyes?”

Yuichiro was going to chide him for trying to force answers his brother didn’t have, but then Muichiro nodded. His jaw dropped as Muichiro lifted up a hand and, after much deliberation, slowly raised up a single clawed finger.

“Upper… One.”

Kyojuro’s eyes went wide. Yuichiro looked to him for answers, but surprisingly, it was Amane who spoke instead.

“Upper Moon One. That would be the strongest of the Upper Moons, and the most powerful demon behind Kibutsuji himself.”

“Wha- You’re kidding, right? You’re saying we were attacked by a demon that strong?! Why?!” Yuichiro couldn’t believe it. The second most powerful demon? Why would someone like that be wandering around their mountain? He couldn't imagine how they were even still alive at this point. And why would Upper Moon One turn his brother into a demon in the first place?

“Why, indeed?” Kyojuro seemed to have recovered from his shock. He put back on that ill-fitting smile. “Unfortunately, we do not know! Still, you are lucky to have survived such an experience!”

Yuichiro scowled. It seemed the only person who would know would be the Upper Moon itself, but the idea of going after someone like that for answers was pure insanity. Well, there was nothing to be gained from looking to the past now, so Yuichiro turned his thoughts to the near future. “…What’s going to happen once we get to the Estate?”

“To Muichiro, you mean?” Kyojuro asked, and he nodded. “That is for the master to decide. Whether he vouches for your brother’s safety or not, no demon slayer would dare to go against his word.”

Yuichiro thought that this master must be someone quite fearsome if all the slayers followed his word without question. But it was only by the master’s words that his brother was still alive now, so he prayed that his mercy would remain once he saw the truth.

“Forgive me for interrupting,” Amane spoke. She had sat by the window all this time, and a crow was perched on her hand. “But I should inform you that we are expecting visitors soon.”

“Huh? Visitors?” Yuichiro repeated. A glance at Kyojuro showed that he was just as confused.

“Visitors? Who might that be?”

“I cannot explain at this time, but do not be alarmed. Master Ubuyashiki has been informed of your situation, and this is a necessary step before we can depart for the manor. They should be here within two nights, so we will remain here until then.”

Yuichiro balked at that. Two nights? They were gonna be stuck here for that long? This manor was a nice place, certainly much nicer than his own home, but still! He didn’t want to be with these people any longer than he had to!

Muichiro’s grip on his hand tightened, bringing him back to the moment. Yuichiro hadn’t even realized he was still holding onto him. “Don’t…worry. Will be… okay.”

A moment of silence passed, Yuichiro realized his breathing and racing heartbeat were slowing. He squeezed Muichiro’s hand back. “Yeah, it’ll be okay…”

He wished he could believe that.

—

It was on their second night in the Wysteria Inn when their mysterious visitors arrived. Yuichiro was thoroughly bored. He'd already changed his bandages and finished his nightly routine, so now he was listlessly watching his brother as he engaged in a staring contest with Kyojuro. Well, sort of, as Kyojuro was blinking quite frequently, shaking his head every few seconds before going right back to staring.

“You should probably stop doing that,” Yuichiro told him. “You’ll damage your brain or something.” Then again, the man was already so strange that it likely wouldn’t make any difference.

“Ah! Then you’ve noticed it as well?” The slayer asked.

Yuichiro nodded. How could he not? He’d realized quickly that gazing into his brother’s demonized eyes had a strange effect. Every time he stared for too long, he’d find his mind clouding over, his thoughts and movements slowed. It was unnerving, so he tried to avoid it as much as he could.

“It is certainly a Blood Demon Art! To hinder an opponent’s thoughts and reactions with mere eye contact! What a fearsome ability!” Kyojuro sounded impressed. “I must do my best to develop a resistance to it!”

Yuichiro glared; did he think that he might have to fight Muichiro in the future? “He’s not doing it on purpose.”

“I understand! There are many examples of passive Blood Demon Arts such as this!”

Yuichiro sighed and continued idly watching his brother. More specifically, he watched the way Muichiro’s long hair lazily floated and fluttered in an unfelt wind. It was just something it did every so often since becoming a demon. “…Is that a Blood Demon Art, too?”

Kyojuro opened his mouth, only to stop as a voice spoke from behind the sliding door.

“Lady Ubuyashiki, your guests have arrived.”

“Please let them in,” Amane ordered, setting the book she’d been reading aside.

The door opened, and Muichiro started to growl. Yuichiro quickly reached out and took his hand to try and keep him calm. Kyojuro also looked on edge suddenly, hand gripping his sheathed blade.

Yuichiro didn’t understand the reason why until he looked at their guests himself. Standing at the door were a woman in a flowery kimono and a young blue-haired boy. They looked normal at first glance, but something about them felt off. It was the same sort of feeling he got looking at Muichiro, of something that seemed human but wasn’t. Then, were these…?

“Good evening,” the woman bowed. “My name is Tamayo, and I am a doctor. This is my assistant, Yushiro.”

The boy, Yushiro, gave an unfriendly grunt of acknowledgement as he warily surveyed the room. Kyojuro looked confused but still on guard. “A doctor? But you are-”

“Demons, yes. But I assure you, we mean you no harm.” Tamayo explained. “Master Ubuyashiki and Lady Amane requested our assistance in regards to the Tokitos’ situation.”

“Huh? What do you-”

“It is true,” Amane interrupted, causing Yuichiro to fall silent. “Master Ubuyashiki and Lady Tamayo have been in contact for a long while now. Like us, she is also opposed to Kibutsuji.”

“What? Is this true?!” Kyojuro looked shocked.

Tamayo nodded. Her eyes narrowed, a barely contained anger lining her words. “It is; I despise that man, that monster, for what he has done. I have spent centuries searching for a way to defeat him once and for all.”

“Wait, what do you mean you’re here about our “situation”?” Yuichiro asked with a suspicious glare.

“Well, as I’ve said, I am a doctor, and I’ve conducted extensive research into demons over many years,” Tamayo explained as she stepped forward and knelt down in front of the twins. “You are Yuichiro, I presume?”

He nodded. “Yeah, I am. And this is…”

He stopped as he caught sight of the expression on Muichiro’s face. He was staring at Tamayo with an intense focus, unblinking. His mouth was set in a hard grimace that showed his fangs and his body was tense and trembling. Yuichiro couldn’t help a sudden feeling of worry; his brother looked like he was in pain. “Um, Mui?”

Yushiro’s slitted eyes narrowed as he put a hand between Tamayo and Muichiro. “Lady Tamayo, you shouldn’t be so close. This one doesn’t seem-”

Muichiro's irises shrunk before he snarled and lunged forward, sinking his teeth into Yushiro’s hand.

“Gah! Get off, you mangy-!” The demon boy yelled and tried to shake him off. Muichiro responded by growling and biting even harder, earning another string of yelling and insults.

“Mui!” Yuichiro shouted in alarm. He looked to Kyojuro for some kind of help or guidance, but the Hashira looked just as lost, his sword half drawn. Clearly the sight of a demon attacking another demon was not a common occurrence. Amane also seemed surprised, but she wasn't a fighter, so it’s not like he could expect her to do anything, anyway.

A ripping sound brought his attention back to his brother, and he almost fainted at the sight of the severed hand held in Muichiro’s mouth, bone exposed and still dripping blood. Yushiro held the stump of his hand and let out a string of curses Yuichiro had never even heard of before now. It was clear that he was more indignant than actually in pain over being attacked, and Yuichiro might have even found it funny if he wasn’t so horrified by the fact that his brother had just ripped someone’s hand off.

“Muichiro!” Yuichiro finally found his voice again. “You drop that right now!”

Muichiro growled in response, and Yuichiro’s temper flared up. “Don’t you growl at me! You listen to me and drop that hand right this instant!”

Did he really just say that? But this whole situation was absurd. To think that a week ago, their lives had been normal. Miserable, but normal. And now here he was, scolding his demonized twin like a misbehaving dog to let go of a severed hand. Was this the gods’ idea of a sick joke? Tears pricked at the corner of his eyes. Why? Why did nothing ever go right for them? What god had they angered to deserve this?

Muichiro’s growling stopped. The hand fell from his mouth and landed on the floor with a dull thud, along with a couple drops of water. Yuichiro looked up and blinked away the tears to see Muichiro crying himself, tears falling freely from his eyes.

“Sorry…” he muttered, hanging his head. “Sorry…”

“…It’s okay. It’s not your fault,” Yuichiro squeezed his hand for assurance. This was all the fault of that damned demon that turned him, the one with six eyes. Anger burned in his chest at the demon that dared to make his brother cry. But as he calmed down, he began to worry for Muichiro's safety. If he attacked that boy, then was there a chance he'd attack humans? Would he have to be killed after all? Yuichiro couldn't bear the thought.

Muichiro let out a hum. His clawed hand picked up Yushiro’s severed one, and he timidly held it out to the boy in question. “Here… sorry…”

Yushiro turned away with an indignant glare. “Keep it, your saliva’s all over it now. Besides, I’ve already grown a new one.”

It was true, the demon boy’s stump had almost completely reformed into an entirely new hand, muscle and skin growing over the bones of his fingers. Yuichiro was both fascinated and a little sickened by the sight.

“How interesting…” Tamayo finally spoke up. She’d been silent throughout the entire affair, simply observing. She moved closer to Muichiro, who shrank back nervously. “Don’t be scared, I just want to ask you some questions. What have you eaten since becoming a demon?”

“…Birds, rabbits…” It seemed like there was something else he wanted to say, but he hesitated and fell silent. Tamayo smiled kindly.

“Have you eaten any humans?”

Muichiro quickly shook his head.

“Then, have you eaten any demons?”

There was another moment of hesitation, and then Muichiro nodded.

“Huh? When did you do that?” Yuichiro asked. It’s not like demons were common on their mountain, and Yuichiro had spent every night alongside his brother since his transformation. If he’d left somewhere in the middle of the night, he’d know. Unless…

“…First night,” Muichiro answered slowly. “Woke up… eating…”

The first night; suddenly it made sense. The thing he’d been eating in the dream. That black thing in his mouth; it’d been the arm of the demon that attacked them.

“How can that be?” Kyojuro spoke up. “Demons do not hunt other demons, at least not when human prey is readily available. It is not in their nature.”

“I already told you, Mui’s different from other demons,” Yuichiro retorted. He felt relieved that given the choice between eating him or the demon, Muichiro had chosen the demon. He felt pride, too; his brother’s kind heart hadn’t been extinguished by his transformation.

“It would seem so. Perhaps after your brother turned, the first thing he ate was demon flesh. If he hasn’t eaten human flesh then, he simply might not have the taste for it. Perhaps that has helped him to resist attacking humans.” Tamayo said thoughtfully.

Yuichiro nodded; that made enough sense. “Is that why he attacked that guy, then?”

Tamayo nodded. “I suspect he’s quite hungry, if he’s only been eating animals up to this point.”

Yuichiro figured as much, though he still couldn’t help feeling guilty at the thought. Logically, he knew there wasn’t anything he could do about it, but he never wanted his little brother to go hungry.

Tamayo reached into a bag at her side and pulled out an empty syringe. She edged closer to Muichiro, who stayed put this time, and spoke in a gentle voice. “I’m going to draw some of your blood for my research. Is that okay, Muichiro?”

His brother nodded, and he didn’t even flinch as the needle entered his skin. Once Tamayo had filled the syringe, she set it aside and took out another small syringe with a red liquid inside. When she looked at Muichiro again, their eyes met. Her calm smile fell into a frown, and she hummed.

“What is it?” Yuichiro couldn’t help but ask.

“How curious; Kibutsuji’s curse is weak within you.” She spoke more to his brother than to him. “An effect of your bloodline, perhaps? I understand you are descendants of the First Breathing users?”

Yuichiro rolled his eyes. Did everyone know about that? “What does that matter? And what’s this curse you’re talking about?”

“Perhaps it matters more than you think. If you are truly descendants of that man…” Tamayo paused, then shook her head. “No, it’s too soon to say. My apologies.”

Yuichiro really wanted to know what the hell she meant by that, but it was clear that Tamayo was done talking about it.

“As for the curse, Kibutsuji has a connection with all of his demons. He can see through their eyes and hear their thoughts, even control them to an extent. Ubuyashiki requested our aid to remove this curse before bringing you two to his estate.” Tamayo readied the syringe as she explained. “It seems the task is already half done, but this medicine will help as well. Is that okay, Muichiro?”

His brother nodded again. Yuichiro reluctantly allowed her to continue, but he still watched vigilantly as Tamayo administered the medicine. Muichiro still didn’t react in the slightest as the needle pierced his arm, but seconds after the liquid was pushed in, his eyes started to drift shut. He wobbled, and Yuichiro reached forward to catch him before he fell over. Panic rose briefly before he realized that his twin had only fallen asleep.

“Do not worry, he’ll simply need to rest for a few hours while the medicine takes effect,” the demon doctor explained. “In the meantime, we must take our leave.”

“Oh? So soon?” Kyojuro asked, voicing Yuichiro’s thoughts. Not that he really cared whether they stayed or not.

“My apologies, but while traveling like this, we don’t have our usual defenses against Kibutsuji’s detection. We wouldn’t want to put you in danger.”

“Fear not, Lady Tamayo! I will handle any demons that dare to come here!”

“Thank you for your assistance, Tamayo,” Amane bowed her head gratefully.

“I am happy to help. A demon who does not attack humans… Such a thing is almost unheard of. But it gives me hope that…” She stopped and stared almost wistfully at Muichiro, then turned to leave, Yushiro right behind her.

“Wait!” Yuichiro called before she could go, a desperate question suddenly springing to life in his mind. “Can… Can a demon be turned back into a human?!”

If anyone would know, it would have to be her, right? This doctor who researched demons? Tamayo looked surprised for a moment, then contemplative.

“…There… may be a way.”

For the first time in a long time, Yuichiro felt hope.

Chapter Text

Once Tamayo and Yushiro had departed, Yuichiro was left with a lot to think about. When Muichiro woke up again, no worse for wear after the medicine, and daylight graced the skies, their little group set out once more. Two more days later, the Ubuyashiki Estate was finally in sight.

Yuichiro couldn’t help a slight feeling of awe at the size of the manor. It wasn’t ornate and flashy as he’d sort of expected, but it was big, bigger than the Wisteria Inn and on an entirely different level from their own home. But then he remembered why they were here in the first place, and his mood soured.

Walking up to the gate, a pair of attendants in a uniform Yuichiro had never seen before bowed. One of the men spoke. “Lady Amane, Lord Rengoku, it is good to see you safe! Please, come with me! The Master and the remaining Hashira are waiting for you!”

“Thank you,” Amane nodded as the man led them around a path to the side. Nervous anticipation built up inside Yuichiro as they walked.

“What’s going on?” He whispered towards Kyojuro.

“If the other Hashira have been called, then that means a trial is to be conducted.”

“A trial?” Yuichiro had a bad feeling about this. “You mean… about Mui?”

Kyojuro nodded. “Indicting a demon into the Demon Slayer headquarters is no small decision. The rest of the Hashira must approve, and Muichiro’s trustworthiness around humans should be evaluated as well.”

“Are you kidding?! It’s been days and he hasn’t even touched another human! Isn’t that enough proof?”

“If it helps, I am on your side, Tokito! I will vouch for Muichiro’s integrity during the trial!”

Yuichiro still didn’t like the man, but admittedly, that did help his nerves. Only somewhat, though. Before long, the man guiding them led them into a large courtyard, bowed, and then quickly departed. He didn’t miss the nervous glance the man gave him as he walked past, however.

Kyojuro placed his hand on Yuichiro’s shoulder and led him along. He brought him to a part of the courtyard next to a large engawa. Sitting on the ground were six people, each distinguishable by their colorful outfits. These must be the Hashira. All eyes went to Kyojuro, then to him, but Yuichiro refused to meet their gazes. He looked to the engawa, where a man sat serenely in the shade.

Was this the Master? He looked young, but there was a strange purple discoloration to his face, running from his forehead and down over one milky white eye. It made him look sickly.

Kyojuro simply led him to stand between the Hashira and the Master, then took his place between a large man whose hands were clasped in prayer and another guy wearing jewelry that reflected the sunlight right into Yuichiro’s eyes. Once Kyojuro was seated, the Hashira bowed as one.

“Master, it is a pleasure to see you in good health!” Kyojuro greeted him.

“And you as well, Kyojuro. I thank you for accompanying Amane on this journey. It would seem it was more eventful than expected,” the Master said. His voice was calm and soothing; it spoke of someone with great wisdom.

“Indeed! It was a truly eye-opening experience!”

On the other side of the line of Hashira, a man in black and white clothes, with bandages on his face and a snake around his neck, looked up and spoke. “Is that it? The demon?”

He pointed to the basket on Yuichiro’s back. His voice sounded unfriendly, and Yuichiro slid the basket straps off his shoulders and clung to it protectively.

The woman sitting next to him, clad in a haori resembling a butterfly’s wings, spoke next with a sweet smile. Her voice was much more measured and curious in comparison. “Young man, what is your name?”

“…Tokito… Yuichiro.” He didn’t trust these people for a second. “This is my twin brother, Muichiro.”

“And how old are you two?”

“Eleven. I’m the older one.”

The butterfly woman smiled sympathetically. It made his blood boil; why was everyone looking at them like they were helpless children?

…Okay, he knew why, but it made him furious nonetheless! He didn’t want or need their pity!

“Yuichiro, please tell us what happened,” the Master spoke, catching everyone’s attention. “It is important we understand your situation, so tell us every detail, no matter how unimportant it may seem.”

The Hashiras’ eyes turned back to him expectantly, and Yuichiro grit his teeth, trying to find his voice through the immense pressure pushing down on him.

“…About eight days ago, my brother and I were attacked by a demon. Our parents are dead, and we live alone in the mountains. The demon’s first slash caught my chest and I couldn’t move, so I don’t know exactly what happened after that, but Muichiro drove the demon out of the house and killed it, I think.”

“Seriously? A scrawny kid took out a demon? Now that’s flashy!” The jewelry-adorned man laughed.

The snake man narrowed his eyes. “Without even a nichirin blade? I don’t believe it.”

“It is possible, though.” The butterfly woman eyed a white-haired man whose skin was covered in scars. The man ignored her, glaring silently at Yuichiro.

“Yuichiro and Muichiro are descendants of the first swordsmen to use breaths. I believe that talent still runs through their blood,” The Master added.

Yuichiro resisted the urge to scoff. As if something as vague as talent was really passed down through blood. Neither he nor his brother had ever touched a sword in their lives. “Like I said, I couldn’t move to see for myself. But then I heard my brother screaming in pain, so I forced myself to get up. By the time I found him, though, he’d already become a demon.”

“How tragic, for two brothers, twins, to suffer such a fate,” the large man cried, tears streaming down his face. His hands were still clasped in prayer. “It is fortunate that you survived.”

“But that’s just it! Mui didn’t try to hurt me!” Yuichiro continued. “When I found him, he was eating something else: the demon that attacked us!”

A brief moment of stunned silence followed. The butterfly woman put a hand to her chin in thought. “Hmm, demons are known to eat other demons if no other food sources are available. We see this all the time on the mountain used for Final Selection.”

“But if his story is true, then there was an injured human in the same area,” the snake man pointed out. “Why would a newly turned and starving demon ignore such easy prey?”

“I… I don’t know,” Yuichiro admitted. “But it’s the truth! Over these past eight days, Muichiro has never once attacked me, or any other human!”

“Man, so unflashy. He's family, so of course you're gonna vouch for him. Yo, Kyojuro,” the flashy man nudged the aforementioned Hashira, “You were with the kid, right? Let’s hear your input here.”

“It is the truth!” Kyojuro crossed his arms and spoke without a moment of hesitation. “Young Muichiro has not attempted to attack a human in all the time I’ve known him! On the contrary, his demonic instincts only came out when faced with another demon on the way here!”

“Oh? That’s quite curious!” The butterfly women smiled. She then poked the arm of a dreary looking man wearing a split patterned haori, the only one who had yet to say a word up to this point. “Tomioka, you’ve somehow been even quieter than usual. What are your thoughts on this?”

“…If it still shows demonic instincts towards demons, doesn’t that mean it’s still wild and dangerous?” The man, Tomioka, finally spoke in a voice that spoke volumes of his reluctance to do so.

The butterfly woman clapped her hands. “Ah, a good point! But then again, if they’re only directed at demons instead of humans, does it really matter? Our own Shinazugawa is rather demonic himself, wouldn’t you say?”

“…I think demonic describes you better, Kocho,” Tomioka muttered. A dangerous aura surrounded the butterfly woman as she looked moments from strangling him.

Yuichiro watched all of this with no small amount of horror and disgust. These weirdos were the greatest demon slayers in the corps? He at least appreciated Kyojuro for his steadfast support of him and his brother, but his respect for the rest of the Hashiras was dropping by the second. “Mui’s not-”

“That’s it! I’ve had enough of this farce!” The white haired man snapped suddenly. Ignoring the shocked stares of his companions, he marched up and, before Yuichiro could even think of protesting, snatched the basket out of his hands.

“Hey!” He shouted, immediately climbing to his feet, but the man ignored him and jumped up into the shade of the engawa.

“Shinazugawa, what do you think you’re doing?” Kocho asked with a dangerous tone in her sweet voice.

“I’m taking action while the rest of you just sit around arguing!” Shinazugawa growled. He threw the basket to the ground and pulled his sword from its sheath; Yuichiro’s breath caught in his throat. “A demon that only eats demons, you say? Sounds like this one’s just a little less picky to me!”

Shinazugawa’s sword stabbed through the basket and Yuichiro screamed.

“Muichiro!”

—

Mui had spent much of the day in a haze. Hours of travel beneath the sun left very little for him to do except watch as the mist around him grew thicker. So he wandered; wandered through the mist in his mind, searching for anything he recognized. Faces, feelings… anything. He could spend hours searching and find nothing but his brother’s face, a face he might’ve also forgotten if it weren’t the same as his own.

It took time for him to pull himself from such dazes, unless something on the outside pulled him free first. So when a sword stabbed through his precious basket, narrowly missing his body, he was caught more than a little off guard. The mist thinned as his brain registered danger beyond the basket.

“Muichiro!”

That was Yui’s voice! It was full of worry and urgency. Seconds later, the lid of the basket ripped off, but something told him he shouldn’t come out yet. He huddled down, trying to make himself small. Seconds passed before his brother called out again.

“Mui, it’s okay! You- Hey!”

Mui’s breath caught in his throat. Yui sounded distressed. Was he okay?

“Let go of me, damn it! Mui!”

His heart stopped. Yui was in trouble! He pushed against the basket, knocking it over to face a group of strange, colorful humans. Yui was in front of them, held by his yukata in the grasp of a man with two different colored eyes.

“Yui!” He crawled out of the basket, ready to leap to his brother’s aide, but the sunlight mere feet away stopped him cold. His body screamed at him to not get any closer, to stay away, and so he found himself unable to move, paralyzed with fear.

Something grabbed his hair and pulled with incredible force. Mui yelped as he was roughly thrown back, away from the sunlight and his brother. His body hit and rolled across the smooth wood flooring.

“Shinazugawa! This is highly uncalled for!” That voice sounded familiar; was it the fiery owl man?

“Shut up! Do you really think a demon can control its instincts around human blood? That’s bullshit, and I’ll prove it!”

This new voice was not familiar, but it was filled with hostility. Mui dug his claws into the floor and righted himself onto all fours, glaring and growling at his attacker. A white-haired man covered in scars glared back with utter contempt, a green and black sword in his hand. Mui could tell by his scent that he was human. Not demon, human. Mui didn’t want to fight him, but he would defend himself if he had to. With the sun shining bright, there was nowhere to run. He growled again in warning.

But instead of attacking, the human put his blade to his own arm and grinned savagely as he drew it across his skin. Blood poured from his wound, the scent drifting to Mui’s nose.

Instantly, the world tilted. Everything suddenly felt strange around him as an overwhelming scent fogged up his head, different from the ever present mist. A thick, rich smell, heavy on his tongue and alluring in a way nothing else he’d ever tasted could compare to. Mui stumbled and struggled to stay upright, his balance suddenly thrown off. All his other senses felt muffled; the world itself moved more slowly.

His mouth watered, saliva dripping as his breaths became heavy and haggard. It was taking everything he had just to keep himself from pouncing at the human with this strange, dizzyingly powerful blood.

“Muichiro!”

Yui’s voice again. It was muffled, slow, but he heard it. Something broke through the fog and flashed across his mind. He was back home. Yui was making dinner, a strained expression on his face. Mui was talking to him, voice full of innocence and emotion.

“Listen! Let’s become swordsmen! I can’t believe that demons actually exist in this world… but if we can do something to help… I bet you and I can…”

You and I can… Save people. Save them from the demons.

Save humans from demons.

But the only demon here was…!

Mui’s eyes widened. He opened his mouth, fangs bared. Then he sunk his teeth deep into the flesh of his left arm. His own blood welled up in his mouth, coating his tongue, and the harsh metallic scent flooded his nose and overpowered that of the strange blood. With a snarl rumbling in his throat, Mui wretched his gaze away from the white-haired human’s blood.

Silence fell. Mui continued to growl quietly around his arm, glaring at nothing, his chest heaving as he tried to calm himself down. His head cleared of the blood-induced dizziness, the mist creeping back in to smother the rage and hunger building inside him.

His own flesh and blood was… not appetizing. Now that he thought about it, the blue haired demon hadn’t tasted very good either. He thought that his first demon had tasted better, but maybe he’d just been too hungry to care. But he could tolerate it. He would not hurt a human. Mui bit down harder, willing the mist to cover up the memory of that strange blood.

Save humans. Protect humans.

Destroy demons.

His blood boiled. The mist churned as rage burned against it.

Destroy demons.

Destroy demons.

Destroy demons.

—

The smile fell from Shinazugawa’s face as an expression of pure shock replaced it. Silence fell over the garden, and Yuichiro saw his chance. He drove his elbow hard into the snake Hashira’s stomach. Distracted as he was, he was caught off guard and let go of Yuichiro’s yukata. The older twin immediately climbed up to the engawa and ran to his brother’s side.

“Mui! Are you okay?” He asked frantically. Muichiro growled and nodded as blood dripped down his arm and into his mouth. His eyes were still dilated with newly-formed slit pupils, narrowed down to cracks in anger. He refused to let go, pulling away as Yuichiro reached for his arm. Yuichiro stopped, recognizing that this was his way of maintaining control of himself.

The Master smiled serenely. He was the only one that didn’t seem surprised by this turn of events. “I believe that answers that, then. We have proof now that Muichiro will not attack a human.”

“But-” Shinazugawa started.

“They have my blessing, Sanemi,” the Master interrupted, soft but firm. “I understand your reservations, but you cannot deny what you have just seen with your own eyes. I ask that you all accept these children as well.”

There was a long, uncertain silence before the snake man spoke. “…With all due respect, Master, what is to become of these two? Surely they must stay here? A demon, even one as strange as this one, can’t be allowed to simply roam free.”

“Indeed, for the time being, Yuichiro and Muichiro will remain here. They can take this time to rest and recover while we decide on more permanent arrangements. I trust there will be no objections to that?”

No one said anything; even Sanemi had begrudgingly fallen to one knee in respect of the Master’s wishes.

“Very well. This meeting is concluded. Goto,” he addressed one of the uniformed staff standing off to the side. “Please take Muichiro inside. As for you, Yuichiro, please remain here. There is something I would like to discuss with you before you rest.”

Yuichiro watched as the Hashira bowed and made their way out of the courtyard. The guy the Master had called looked unbelievably nervous as he grabbed the basket and approached Muichiro. The child demon stared back with wide, empty eyes, the slit pupils gone again. He even let go of his arm as he crawled back into the basket, the man looking as if he might faint the whole while. He ran off hastily after that, and Yuichiro's eyes slid to the trail of his brother's blood staining the floor.

What the hell? Even if it was logical for the Demon Slayer Corps to distrust a demon, who the hell would put a kid through this? That guy provoked and attacked Muichiro; he had every right to defend himself, yet he would have been killed if he had done so. What kind of trial was that?

Soon it was just him and the Master left in the garden. “Please, come sit down.”

Yuichiro glared suspiciously, but try as he might, he couldn’t detect any duplicity in the man’s words. He sat down a few feet before the Master and grimaced; that purple sickness on his face looked even worse up close.

“You have my sympathies for what has befallen you and your brother. It cannot be easy to have so much responsibility at a young age.” The Master began after a moment of quiet.

Yuichiro shrugged. He didn’t need any more pity, but the man sounded genuinely sincere, so he found it hard to get mad. Or maybe he was just too tired after everything that had happened today. “Yeah, well, you’re the reason my brother’s still alive, right? So… thank you.”

The Master chuckled. “There is no need for thanks. In truth, I foresaw this event.” At the sight of Yuichiro’s wide-eyed shock, he continued. “My family is blessed with a certain level of future sight, you see, and I was granted a precognition on the night of the demon attack. I feared for your safety, which is why I sent Kyojuro to accompany Amane. However, I could not be truly sure of what the vision meant until Amane sent me the message explaining your situation.”

“Huh? You mean, you knew that Mui became a demon?”

“As I said, the vision was vague. You are both very special children, so I wished to protect you both.”

“Because of our bloodline, right?” Yuichiro asked bitterly. “You think we can learn this “First Breathing” because our ancestors did, right? Well sorry to disappoint you, but only one of us wanted to protect people from demons, and he’s a demon himself now, so you’re out of luck.”

“I understand. It is true that your bloodline’s potential is what drew our interest to you in the first place, but I will not begrudge you for not wishing to fight. The life of a demon slayer is perilous, and it's hardly fair to ask anyone to lay down their life for our cause. If you do not wish to fight, we can arrange for a new home for you.”

“And what about Mui?”

“Admittedly, his condition complicates matters significantly. Even with my approval, many of the Hashira and corps members as a whole will be wary of his presence here. However, Tamayo has offered to take Muichiro in if necessary. I trust that she will be able to best meet his needs while keeping him safe.”

Yuichiro glowered at the proposal. The mere suggestion that the two of them be separated, that Muichiro should spend the rest of his eternal life with demons instead of his family, was insulting. Spiteful words towards the leader of the Demon Slayers bubbled up in his throat, but he knew better than to spit them out, not when their wellbeing was entirely dependent on this man’s good graces.

Despite the Master’s seeming honesty, despite his proposals towards other options for the twins, in reality, there was no choice at all. There was only one way Yuichiro could stay with his brother, one way that he could maybe get his real brother back someday.

His fists clenched, nails digging into his skin. “…Tamayo said there might be a way to turn Mui back into a human. But it depends on collecting the blood of powerful demons.”

The Master nodded. “No doubt she means the blood of the twelve Demon Moons. It is certainly no easy task; the Demon Moons are elusive and powerful; even the Hashira have yet to see an Upper Moon and live to tell of it.”

“But we did. Or, Mui did,” Yuichiro recalled. Six eyes, he had said. Upper Moon One. Certainly, the blood of that demon would be enough for Tamayo’s research. But could such a monster even be killed? It seemed impossible, but…

…but he had to try. For Muichiro, the little brother he couldn’t protect. Yuichiro knew he wasn’t one of the chosen ones; he wasn’t as strong or kind as his brother. But there was no other choice now.

“I… I need to save him. I need to kill the demon who did this to him! To do that… I need to become a demon slayer!" He bowed his head to the floor, desperation triumphing over pride. "So please, let me join the Demon Slayer Corps!”

For just a moment, the Master looked shocked. And then he smiled.

A kind, proud, and sad smile.

"Very well. We are grateful to have you, my child."

Chapter Text

“Tokito, I was told you wish to begin training as a demon slayer!”

Kyojuro’s voice was booming as always. Yuichiro turned away from the game of shogi he was playing with his brother. Somehow, despite seeming to have regressed in maturity, Muichiro’s skill at the game was as sharp as ever. Yuichiro didn’t consider himself a sore loser, but he was still losing, so a part of him was grateful for the interruption.

“Ah, I see you two have changed clothes! Wonderful!”

Yuichiro shrugged. Indeed, when he first came to this room, he’d found two sets of clothes laid out for him and his brother. Yuichiro himself was wearing a dark blue samue kimono with loose black pants and socks, while Muichiro wore a similar outfit consisting of a pale blue kimono with white pants and socks. Both kimonos were also adorned with the same mist patterns as their old yukatas, making Yuichiro question when exactly these were prepared for them. Had the Master or Amane always expected them to come here eventually?

Still, the older twin had to admit that these clothes were much softer and comfier than their yukatas. The bandages around Yuichiro’s chest had also been freshly changed as soon as he’d completed his talk with the Master, so he was quite comfortable now and in a relatively good mood.

“Yeah, they’re, um, nice,” he finished lamely. He really wasn’t used to this much hospitality from people he barely knew.

“I am glad you like them!” Kyojuro said. “And on the subject of training, I would be happy to take you on as my tsugoku if you so wish!”

“Tsugoku?” Yuichiro tilted his head, Muichiro mimicking the movement.

“A tsugoku is one who trains under a Hashira with the intent of taking up their position someday! However, it is by no means an easy task! To be a demon slayer, one must train to their utmost limits! Demons are strong, fast, and unpredictable! You must never underestimate them! Train hard, master a breathing style and Total Concentration Breathing, and-”

It had been a long day, and Yuichiro was too tired for this. His good mood was souring and just listening to the man’s booming voice go on and on was giving him a headache. He tried to find a moment to interject between his speech, but Kyojuro kept talking without taking a single breath. What was this man’s lung capacity?

He wasn't even looking at him at this point, just yelling at the air.

This guy's seriously a weirdo...

Finally Kyojuro turned to address him directly. “Young Tokito, have you ever wielded a sword before?”

Yuichiro shook his head.

“I see! In that case, we should determine what breathing style would suit you best! Each is different, and it is important to find the one best suited for your body. For example, as the Flame Hashira, I use the Flame Breathing style! As my tsugoku, it would be best if you could learn this style as well!”

Yuichiro was silent as he considered this. Could he be suited to Flame Breathing? He supposed there was only one way to find out. Though he wasn’t sure he even wanted to be Kyojuro’s tsugoku in the first place. He wondered if any of those other Hashira would make good teachers…

…No, Kyojuro was really his best option, wasn’t he? Damn it.

“Ah, but we should really start with the basics of sword training before we move onto breathing! Come, Tokito, let’s take this outside!”

“Huh? Um, okay…” He was really too tired for this, but it seemed he had no way out. He turned to his brother. “Mui, stay here. I’ll be back soon.”

With that, he followed Kyojuro out of the room to begin their training.

—

Mui was bored as he watched Yui speak to the fiery-haired, owl-eyed man. Normally he was content to sit and let Yui make decisions for him, but here in this new place, he felt strangely antsy. Mist crept in at the edges of his vision and he blinked to clear it. It seemed like Yui and the owl man would be here for a while. He needed to move.

Where could he go, though? He had a feeling that, even though the sick human - Master, was his name Master? - approved of him, most humans would still be scared of a demon wandering alone. So he couldn’t go anywhere where there would be people. Where was a place where people wouldn’t be? Well, it was nighttime; maybe most humans would be asleep.

“Come, Tokito! Let’s take this outside!”

Huh? Take what outside? Mui felt like he had missed something.

“Huh? Um, okay…” Yui turned to him with an uncertain look and pointed at the floor. “Mui, stay here. I’ll be back soon.”

Mui nodded, having no intention of listening. He watched Yui and the owl man leave the room, the sliding door shutting behind them and leaving him in empty silence. Mui frowned; with Yui out of his sight, the usual hollowness ate at his mind and stomach. His heart beat faster and the mist crept into his vision again.

He needed to move.

The hallway was silent as Mui opened the door and looked around. Cautiously he crept out, only to freeze as the floorboard creaked beneath him. The floor was well maintained, so to humans the noise was probably unnoticeable, but to his demon hearing, it was loud as a scream. Mui furrowed his brow and took another step. Wisps of white rose from his feet as he touched the ground, not making the slightest sound this time.

Satisfied, he moved around the manor slowly, senses on high alert for any approaching humans. Luck was on his side, though, and no one came his way. Eventually Mui came to an open door and peeked in, eyes going the slightest bit wide at the rows of shelves filled with books. Creeping inside, there seemed to be no one around, so he stood up and walked freely.

Mui browsed the rows of books, clawed hand reaching towards them but stopping just short out of concern he’d damage them. There was a mix of old and new looking books, but he found himself struggling to read most of the titles, the kanji too complex for him. But after a few minutes of searching, he came across some books with very simple titles. “Flame”, “Water”, “Wind”; he wondered what they referred to. Curious, he pulled one out with utmost caution; these were old, worn books, and he really was worried his claws would catch on them.

He flipped to a random page and found what seemed to be instructions for sword techniques, complete with illustrations. Hadn’t the owl man said something? Something about breathing? He couldn’t remember.

But when he looked at the shelf again, something caught his eye. One book with the kanji for “Mist” on its spine stood out to him, and he pulled it out a little quickly, thankfully not tearing it. A familiar design adorned the cover, though it took him a moment to place it, until his eyes wandered to the kimono he wore, the same design repeated throughout.

Something resembling excitement rose up within him upon realizing the connection. A barely perceptible smile adorned Mui’s face as he sat down and opened the book. The words were still hard to understand, but it was the pictures that drew his interest the most anyway.

“Oh, I didn’t see you there! Can I help you?”

Mui froze. He was so engrossed that he had failed to notice the human who entered the room and walked right up behind him. He turned around and looked up at the woman in some uniform he didn’t recognize. For just a second, their eyes met.

The woman screamed. Mui jumped and leapt for the top of the bookshelf, the Mist book still clutched in his hand. “Sorry!” he shouted as he ran along the shelf and jumped down behind her, sprinting out the door as fast as he could. “Sorry, sorry!”

Yui was not going to be happy about this.

—

Yuichiro coughed; his lungs ached. His whole body ached; how was he in this much pain just from trying to breathe properly?

At first, his training had just been swinging a wooden training sword for an hour. While it was certainly tiring, it wasn’t painful; in fact, it felt shockingly natural to his body. Then Kyojuro tried to teach him about breathing.

This whole Total Concentration Breathing concept made little sense to him. Just breathing a certain way could make you as strong as a demon? He’d pulled it off once, and had almost immediately gone into a coughing fit. And the Flame Hashira said he would be expected to do this at all times as a demon slayer?! Were these people insane?!

The claw wounds really weren’t helping either, stinging every time his chest heaved from the strain of breathing. He recalled that Kyojuro had said something about the Insect Hashira, Shinobu, being skilled with medicine. He would have to try asking her if she had anything that could dull the pain.

The young boy tried to compose himself as he stopped in front of the sliding screen door to his and Muichiro’s room. He could see a moving silhouette behind it as he pushed the screen aside. It seemed his brother was up and-

“What are you doing?”

Yuichiro took in the scene before him of his younger twin wielding a large stick and swinging it down in an arc, over and over again. He seemed focused, though it was hard to tell since his eyes were as hazy as ever. Upon hearing Yuichiro’s voice, however, he stopped and turned, the stick falling to his side.

After a moment of silence, Muichiro raised the stick triumphantly in the air, his face still blank. “Sword training!”

“Mui, that’s a stick.”

“Sword training!” He shook his head and repeated himself insistently.

“Where did you even get that? Did you go outside?” Really, right after Yuichiro had told him to stay put? What if someone saw him out alone?

Muichiro’s silence was a dead giveaway; he always clammed up when he was guilty of doing something bad. That at least hadn’t changed when he became a demon.

“No one saw you, right?” Muichiro shook his head. Yuichiro sighed. He really couldn't blame his brother for getting bored, left alone as much as he was. “Fine, it’s no big deal, then. Just tell me if you’re going to go somewhere, please?”

Muichiro nodded enthusiastically, or at least it seemed that way to Yuichiro. He liked to think he was getting better at reading his demon twin’s emotions behind his stoic outer shell. He watched as Muichiro went back to his training, positioning his feet with his stick grasped tightly before thrusting forward at an upward angle. He frowned, pulled the stick back and adjusted his stance a little, then stabbed again. This time, Yuichiro thought he saw a wisp of fog around the stick’s tip.

“Hey, is that a breathing form? Where did you learn how to do that?” Yuichiro asked accusingly. His brother’s movements were too deliberate to be something thought up on the spot. Kyojuro had shown off something similar, one of his own Flame Breathing techniques. Yuichiro had been in awe of the flames roaring from the blade, not really there but confounding his eyes all the same.

Muichiro didn’t respond. He stayed absolutely still and expressionless. Yuichiro looked around the sparse room, and then his eyes fell on the basket, open with the lid lying next to it.

“Mui, what did you do?” Again, silence. Yuichiro narrowed his eyes as he moved towards the basket.

Muichiro moved in the blink of an eye, putting himself between his brother and the basket with outstretched arms.

“Don’t get mad!”

“I’m not getting mad!”

“You are!”

Yuichiro opened and closed his mouth. Damn it, he was right. He took a deep breath and unclenched fists he didn’t even realize he’d been clenching.

“…I’m not gonna get mad, Mui. Just be honest.” Gods, he sounded like Mother.

Muichiro looked aside nervously, then turned around and crouched to pull something out of the basket. He turned back with an old book in his claws and held it out to his twin.

“Mist… Breathing.”

“Mist Breathing?” Yuichiro repeated. The book did indeed bear the same mist design as their kimonos; maybe that’s why Muichiro took interest in it? He opened it up to find what seemed to be a journal giving detailed instructions of Mist Breathing forms. The kanji was a bit beyond his reading level, at least without a dictionary, but the pictures were detailed enough to make up for it.

“Where did you get this?” He asked.

Muichiro frowned and bowed his head. He pointed towards the open door behind Yuichiro.“…Went out there.”

Damn it, why did his brother never listen to him? But Yuichiro promised not to get mad, so he held his tongue. “Fine. It’s fine, so long as no one saw you… No one saw you, right?”

“…Sorry, Yui!”

“Mui, you-!” He squeezed his eyes shut and shook his head. Don’t yell. Don’t yell! He opened his eyes and sighed again. “What am I gonna do with you…”

His thoughts were interrupted when Muichiro abruptly shoved the stick into Yuichiro’s hands. He looked down, uncomprehending, until his twin explained.

“Sword training!”

Well, sort of explained. But after a few seconds, Yuichiro understood what he was saying. “You… want me to practice Mist Breathing?”

Muichiro nodded and smiled. A small smile, nowhere near the beaming grins common in the happier years of their life, but for just a moment, he saw his human brother again.

Yuichiro’s vision blurred, and he realized there were tears in his eyes. He quickly blinked them away and nodded. “Okay.”

Muichiro’s smile grew wider. He leapt forward and embraced Yuichiro in a sudden hug. The older twin froze, his thoughts grinding to a halt and the stick almost falling out of his grip. Then Muichiro let go and ran over to the screen doors leading outside. He shoved them open and leapt out into the darkness, leaving Yuichiro still frozen where he stood. It was a few more seconds before he finally shook himself out of his daze and followed after his brother.

The moon and stars shone overhead, providing enough light to see by. Muichiro stood out on the grass, evidently having found another thin tree branch to use as a sword. Yuichiro moved to stand across from his twin, who raised his “sword” with focus. “Watch!”

He swung down in a perfect arc. Then he did it again, and again. Watching his brother, Yuichiro felt something: the old sibling competitiveness that always reared its head whenever one twin was trying something new. No matter what it was, from fishing to chopping wood, both twins always needed to prove they were better than the other at it. It was the same here, too.

He raised his own “sword” and swung it down, still amazed at how natural it felt. Could it be that swordsmanship really was in their blood? But it didn’t matter, he decided. Talent would only go so far. He would become a demon slayer and save Muichiro on his own merits.

The two boys practiced side by side late into the night and then beyond, until the first light of day forced them back inside. Utterly exhausted, Yuichiro collapsed on his futon almost immediately. The last thing he felt before sleep claimed him was Muichiro lying down beside him, clawed hand gently clasping his own.

Chapter Text

It was hard to believe that four months had already passed.

Yuichiro felt like he had spent every waking moment not spent eating or sleeping on training. During the day, he’d train with Kyojuro, or one of the more tolerable Hashira like Shinobu or Uzui, or just by himself if no one was around. He’d train until he felt like his limbs would fall off. Then at night, he’d spar with Muichiro until the sun rose or exhaustion claimed him, whichever came first. It went on like that, day after day, as he steadily grew stronger and more capable in his physical abilities and swordsmanship.

He’d even managed to become proficient at Total Concentration Breathing. However bizarre the idea of it was, he couldn’t deny the results. He could run farther, jump higher, and put more strength into his sword swings than ever before. The difference between now and four months ago, when he was just a poor woodcutter’s kid, was staggering.

And soon, all of that training was about to pay off, one way or the other.

“You will be undertaking Final Selection soon, I’ve heard! Congratulations!”

“Oh, um, yeah, I guess. Thanks,” Yuichiro mumbled through a bite of onigiri. He and Rengoku sat at the edge of the engawa, eating snacks and enjoying the sunshine, when the Hashira brought up the subject of Final Selection. Yuichiro didn’t think being qualified for jumping into a seven-night death pit was grounds for celebration, but at this point, he was used to Kyojuro’s attitude. “I mean, Master Kagaya says I’m ready, so…”

Rengoku nodded. “Indeed, if the Master believes so, it must be true! And after only four months, too! I can see why the Master sought you and your brother out! Such talent and growth in so short a time is exceptional! And in Mist Breathing too, a truly difficult style!”

“It’s because of Muichiro. He learned all six forms in just a few days, and he’s helped me train all this time.” Indeed, Muichiro was the truly talented one. Yuichiro gave it his all, but Muichiro took to Mist Breathing like a fish to water. Everything, from his form to his swings, was perfect, precise, and elegant. Yuichiro could only wish for his own forms to look that beautiful one day. His swings were stronger but choppier; more force, less finesse. Like a roiling fog that swallowed up everything it touched.

But for Muichiro, wielding a sword was as easy as breathing.

No, for Muichiro, wielding a sword was easier than breathing.

“…On the other hand, he can’t seem to learn Total Concentration Breathing. He’s trying, I’ve seen him practicing every day. But he starts choking at the same point every time. It’s like his lungs aren’t getting any stronger even with all that training.”

Call it petty, but Yuichiro was glad to have one thing he exceeded his brother at. He wasn’t quite at the level of Total Concentration Breathing Constant yet - sleeping was still an obstacle - but he was getting there.

Kyojuro looked thoughtful. “Hm! Most likely, they are not! After all, demons regenerate wounds almost instantly, returning to their original state! But think about how humans grow stronger through training! We damage our muscles, and allow them to heal stronger! We push our bodies to the brink of death again and again to draw out greater strength! A demon cannot do that!”

Yuichiro nodded. That certainly made sense, but he grimaced at the thought of telling Muichiro that. To tell him all his effort had been for nothing... “So, you’re saying it’s impossible?”

“Not necessarily! We still don’t understand everything about demons and how they grow stronger! And your brother is quite different from other demons; he may surprise us yet!”

Yuichiro hummed in thought. Maybe if he told Muichiro what Kyojuro had said, he’d be able to figure out a way around his body’s limitations? The first step to solving a problem was understanding it, right?

The sound of shuffling feet behind him caught his attention. “Oh, Mui, you’re awake?” It was still early afternoon, and even with autumn transitioning to winter soon, the sun wouldn’t set for many hours.

Muichiro didn’t say anything as he stopped shy of where the sunlight touched and abruptly sat down. His turquoise eyes were duller than usual, his expression listless. Yuichiro’s heart ached to see him in this state.

“He needs to eat something,” he told Kyojuro. "It's been too long."

Muichiro was indeed quite different from other demons. His skill with the blade was one thing, but what was really unusual was that he didn’t need to eat much. Other demons were rare in this area, so he demonstrated a remarkable ability to go weeks without any sustenance. But that didn’t mean he could just starve himself with no ill effects. The longer Muichiro went without eating, the more he got like… this. Quiet, unresponsive, and lost in whatever was going on inside his head.

Yuichiro still remembered the incident three weeks into their arrival, when Muichiro had entered a near catatonic state. They’d brought in Shinobu to examine him, but she couldn’t find anything wrong besides the clear malnutrition. She'd carried him into the forest that night, and he’d been unresponsive until they stumbled upon a demon, upon which he'd come to life with all the fury of a rabid dog, ripping off limbs and tearing into constantly regenerating flesh. Even after Shinobu had killed it, he was still trying to eat the poisoned demon’s flesh. She came back before morning, carrying a knocked out Muichiro covered in blood that wasn’t his, and scaring the hell out of his panicking older brother.

After that, Muichiro was taken out hunting once a week. When no one of suitable strength was around to take him, he was fed with blood bags delivered from an anonymous source. Not that Yuichiro didn’t already know where the blood came from; how many friendly demons willing to donate blood could there possibly be?

“It is a sad state indeed,” Kyojuro nodded, a rare frown on his face. “Were it not for my mission, I would take him out hunting tonight myself!”

Right, Kyojuro would have to leave before the sun set to investigate some village far off in the east. There were no other Hashira at the Ubuyashiki Estate either right now, and the next shipment of blood bags wouldn’t arrive for three more days. And to make matters worse, Yuichiro himself would have to leave for Final Selection in two days. He hated the thought of leaving his brother like this; there was a chance he wouldn’t come back and-

Yuichiro shook his head; he couldn’t think like that. Muichiro needed him! But life was cruel and unfair; he knew that better than most. If something were to happen… “Hey, Kyojuro?”

Kyojuro’s gaze locked on his curiously. “If… If I don’t come back from Final Selection… take care of Muichiro, alright? Please?”

For a moment, Kyojuro looked surprised. Then he smiled kindly and placed a firm hand on Yuichiro’s shoulder. “Fear not, young Tokito! I have utmost faith that you will pass Final Selection!” Then in a softer voice, he added. “But, no matter what comes to pass, I will care for Muichiro as if he were my own little brother. You have my word.”

Yuichiro smiled gratefully. His racing heart felt just a little more at ease.

—

That night, Yuichiro found himself restless and unable to sleep. He opened his eyes and glanced towards the corner of the room, where Muichiro sat, still and almost lifeless if not for his steady breathing. Normally the two of them would train to pass the time, but it’d been almost two weeks since the demon had last eaten anything; training was out of the question in this condition.

Yuichiro rolled over and looked at the other side of the room, where his clothes and the temporary nichirin blade he’d been given for Final Selection sat against the wall. His thoughts again turned to Muichiro, barely cognizant of anything around him, like a doll. And Yuichiro couldn’t do a thing about it; how unfair was that?

Unless…

The thought hit him abruptly, and before his mind had time to reject it, he was already up and grabbing his clothes and sword. “Muichiro.”

Muichiro turned his head at the sound of his voice. Yuichiro crouched down in front of him with the basket in hand. “Get in, we’re gonna get you some food.”

Maybe it was his imagination, but Muichiro’s eyes seemed to glow a little brighter at the mention of food. He crawled into the basket quickly and quietly while Yuichiro changed clothes. Once finished, he swung the straps over his shoulders and made his way to the door.

Stepping out into the open air, his mind tried to remind him what a stupid idea this was. There was a reason only the Hashira or higher ranked slayers took Muichiro out hunting. But then again, Yuichiro was already going to be fighting demons at Final Selection in two days’ time, so why was it a big deal if he fought them here first? It was basically extra training, a final bit of practice before the exam.

It didn’t take long to jump the walls surrounding the estate and make his way into the forest beyond. It was dark and quiet, the trees filtering much of the moonlight. Yuichiro drew his sword and decided it would be best to stick to the paths where the light was brightest. He walked along the road for about ten minutes, trying not to stray too far from the manor, but also knowing he might have to in order to find any demons.

The air was crisp; winter was approaching fast. A shiver ran down his spine, and it took him a second to realize it wasn’t from the cold. Muichiro was restless inside his basket.

Yuichiro went on alert. “Mui, what-”

A sense of danger ran through him, coming from his right. Yuichiro stepped to his side and swung his sword, hitting something that sprayed blood on impact. That something appeared out of thin air, wet and slimy as it hit the ground.

“Oh? You sensed me…” A voice rang out, low and sinister. Yuichiro froze for only a second before he readied his sword again. In the corner of his eye, a dark shape appeared, and he turned to see a humanoid figure perched in a tree who was definitely not there a second ago.

It was obviously a demon; humans didn’t have green, scaly skin, or a curled tail, or long claws. The demon opened its mouth in a grin, revealing sharp teeth, as a whiplike, bleeding tongue snaked out. With a sickening sound, the end of the tongue suddenly regenerated, and Yuichiro realized that that was what he had slashed.

“You a demon slayer, kid? You don’t look the part,” the demon chuckled before it suddenly vanished. Yuichiro shifted his stance and looked around frantically, trying to locate it. What was going on? Was it turning invisible? Was this a Blood Demon Art?

“Gotcha!” He heard the demon’s voice right behind him. But just as he started to turn, the lid of the basket on his back blew off.

“Raaaaaggh!” Muichiro let out a feral scream, feet kicking off the basket and knocking Yuichiro forward. He struggled to regain his balance as he heard the sound of claws tearing flesh, and the other demon’s surprised shout turned to one of pain. Yuichiro turned back just in time to see his brother pinning the demon to the ground, fangs digging into its shoulder as blood dripped from a deep scratch on his cheek. Muichiro’s claws sank into its arms, and he raised a foot and slammed it down on the demon’s thigh. A sickening snap brought forth another roar of pain.

It suddenly occurred to Yuichiro that while this was his first demon encounter, his brother had already fought and eaten plenty of other demons by this point.

Eventually, the demon managed to knock Muichiro off with a well placed kick to his abdomen. Muichiro reeled back, and the demon’s tail wrapped around his waist and tossed him sideways into a nearby tree.

“Muichiro!” Yuichiro almost ran to his brother, but he reminded himself that his twin was a demon; he’d be fine. He raised his sword again as the demon leapt back up into the trees.

“What the hell? What’s a demon doing with a demon slayer?”

“What, do your eyes not work? We’re twins, stupid! Doesn’t matter if we’re human or demon!” Yuichiro spat harshly. He hoped to goad the demon into abandoning its higher ground and attacking recklessly.

It worked, though not quite in the way he was hoping. The demon snarled and disappeared again, and Yuichiro had no way to know what direction it would strike from.

“Shit… Come on, focus!” Yuichiro closed his eyes and listened. There was a snap behind him, and his eyes flew open.

“Mist Breathing, Third Form,” he readied his sword and breathed deep. “Scattering Mist Splash!”

He spun around, sword swinging in a wide circle. A spray of mist and blood spurted out as the demon’s tongue flew off once again.

The demon reappeared, looking more than irritated. “Gah! Stop doing that, you little-!” It didn’t get to finish as Muichiro tackled it from the side. His fangs sank into its exposed neck and tore savagely, and Yuichiro couldn’t help but wince. His sympathy was very short-lived, however, as the demon’s tail whipped around and skewered Muichiro through the stomach, drawing a muffled yelp from his twin. Yuichiro gasped and grit his teeth, his grip on his sword tightening.

“Damn brat! I’ll rip you apart and- Gah!”

Muichiro’s claws slashed through the tail with ease, but the demon’s foot kicked him off again a moment later. As he flew back, taking a chunk of the demon’s flesh with him, Yuichiro jumped in with his sword aimed towards its neck. But the demon’s tongue shot out, already healed, and Yuichiro was forced to dodge. The whiplike tongue barely caught his shoulder instead of his head, drawing a shallow cut and a hiss from the boy.

Yuichiro stumbled back and the demon climbed to its feet. The cut stung, but it would take a lot more than that to stop him as he raised his sword to strike once more.

But the demon didn’t attack. “What’s your problem, kid? I wasn’t even doing anything, just minding my own business. Then you come around, carrying a sword and a demon? What gives?” Its stance relaxed as it seemed genuinely curious about the answer.

“I need to feed my brother,” Yuichiro answered simply.

“Huh? Then get him a human to eat and leave me alone. This ain’t got nothing to do with me.”

Yuichiro hesitated. He supposed he couldn't fault the demon for not understanding why he was hunting other demons to feed his brother. And admittedly, he had been the one to come out looking for a fight. But the demon had still struck first. But maybe it had only done so because it felt threatened by his nichirin sword? His sword hand shook, and he missed the way the demon’s lips curled in a smile.

“Yeah, you came out hunting for me. So it’s justified if I defend myself, right?”

The demon leapt forward at high speed with its claws raised. Yuichiro gasped and froze for just a second, but it was a second too long. Even as he raised his sword to block, he knew it wouldn’t be enough. Then suddenly, something else came between them. Muichiro stood in front of his brother with his arms thrown out to shield him.

Yuichiro’s heart leapt into his throat. “Muichiro!”

“Blood Demon Art,” Muichiro’s voice was deathly calm. “Haze.”

The entire area was instantly engulfed in a thick white mist. The demon was thrown off, its claws slashing through empty air as Muichiro’s clothes fell to the ground. Yuichiro stumbled back as well, his mind racing. Where had Muichiro gone? He had been right in front of him, and yet now he couldn’t see him at all.

The demon suddenly cried out in pain, the mist shifting enough for Yuichiro to see its severed arm fall to the ground. He thought he caught a glimpse of his brother’s glowing eyes and black hair before a slicing sound signaled the other arm coming off. The demon reeled back, an expression of fear on its face before it turned invisible, but the surrounding clouds swirled around it as it moved. The distortions in the mist moved backwards, and Yuichiro realized it was trying to run away.

“Oh no you don’t! Mist Breathing, Fourth Form: Shifting Flow Slash!” Yuichiro crouched low and shot forward. Mist swirled around his sword, maybe imagined, maybe real, but it almost seemed to push him along, adding to the strength of his technique.

Muichiro’s eyes glowed in the haze, and a scratch and spray of blood from the invisible demon told him where to aim. With a final, focused swing, his sword sliced through the demon’s neck, its head becoming visible as it separated from the rest of its body.

As the body collapsed, Yuichiro stood tall and sighed in relief; it was over. The mist around him receded as quickly as it had come, coalescing together into a humanoid shape. Then it solidified, and Muichiro appeared before him, alive and…

Yuichiro’s face went bright red. “Put some clothes on!” He shouted as he picked up his brother’s discarded kimono and tossed it in his face. Muichiro looked confused before looking down at himself. He quickly wrapped the kimono around his body and looked away awkwardly.

Yuichiro groaned, still feeling the second hand embarrassment. He thanked the gods that the demon’s head had already crumbled away. In fact, the whole body was breaking apart into ash and scattering to the wind. He stared in wonder at his first demon kill. The idea was surreal; he’d killed plenty of animals in his life, but this was something that could talk, that could feel. Even if it was utterly twisted, the demon had been alive.

A muffled growl and a ripping sound broke him out of his existential thoughts, and he turned to see Muichiro tearing a chunk out of the demon’s arm. “Mui!”

His brother froze, flesh still hanging from his teeth. He let out a pitiful whine like a puppy. Yuichiro sighed and waved a hand. “Nevermind, keep doing what you’re doing.”

Muichiro’s irises lit up as he went back to his meal. The arm was disintegrating even as he bit into it, and Yuichiro hoped he could get his fill from it in time. He went back to watching the rest of the demon crumble away, reminding himself that this demon had probably eaten plenty of humans without a second thought and had tricked him into lowering his guard before attacking. It could burn in hell for all he cared.

It was then that Yuichiro noticed the mist creeping along the ground towards the corpse. He glanced at Muichiro, the fog seeming to rise from the ground beneath his feet, then back to the corpse that was now swallowed up by the mist. It seemed like the crumbling pieces of the demon were now trapped in the fog, slowly vanishing inside it. Was he somehow eating the demon through the mist? Demon biology never ceased to amaze and horrify.

A sting in his shoulder reminded him of his injury. It was fairly minor, all things considered, but he probably should get it treated sooner than later. Especially with Final Selection coming up. He just hoped that no one at the estate would question where it came from. Maybe he could pretend it was from a training accident?

A peaceful quiet fell over the forest. The arm Muichiro had been eating had disappeared by now, along with the rest of the body, and the young demon went to collect his clothes. As he dressed, Yuichiro figured now was the time to address the unspoken topic hanging between them.

“So… that was a Blood Demon Art, huh?”

Muichiro looked at him with no small amount of worry. Now that he had eaten, his emotions were heightened, at least for the time being. “…Yeah.”

“…How long have you been able to do that?”

Muichiro shrugged. “Don’t know. A while…”

Yuichiro hummed. Suddenly it made sense, how he could never feel his brother’s weight inside the basket. But if he’d been turning into this mist form every time, that meant Muichiro had had his Blood Demon Art as early as four days into his transformation. Was that normal?

But that Blood Demon Art had almost certainly saved his life tonight, so the real question was: did it matter?

He didn’t know, and honestly he was too tired to worry about it. He had a feeling he’d sleep very well after all this. After he’d gotten his wound bandaged, of course.

“Come on, Mui, let’s head back.”

Muichiro nodded and held out his hand. Yuichiro grabbed it tight, a small, irrational part of him afraid he might turn to mist and vanish before his eyes. But the feeling of his twin’s hand in his stayed solid and real the whole way back.

Chapter Text

“Yuichiro?”

Yuichiro finished tucking his sword into its sheathe before turning to the door. Standing at the doorway was Amane, a smile on her face and a wrapped box held in her hands.

“Miss Amane?” Yuichiro tilted his head. Though he’d never openly admit it, he’d warmed up to the Master’s wife over these past four months. She took care to make sure he and his brother were clean and fed, and she was always so gentle. Muichiro didn’t remember their mother and father after becoming a demon, but sometimes he’d find his twin curled up at night with his head in Amane’s lap, the white-haired woman running her hands through his long hair. Just like their own mother used to do.

“Yuichiro, are you okay?” Amane asked, stepping closer. Her expression was one of concern, and Yuichiro realized it was because he was tearing up. He quickly wiped the wetness away and stood tall.

“Just thinking, that’s all. Don’t worry about me,” he insisted.

Amane knew better than to pry, so she smiled and held out the box. “Some snacks for the journey. They should last you until you reach Mount Fujikasane.”

Yuichiro took the box. It felt heavy; she must have packed quite a bit inside. She really was like their mother. He was sure Muichiro thought of her that way, but it was harder for him to do the same. The deaths of their parents were still open wounds on his heart, and sometimes he wished he could just forget them too.

But he couldn’t let any of those warring feelings show, not now. “Miss Amane… thank you.”

Her smile was so gentle and encouraging. “Please, come back safe. Master Ubuyashiki and I have complete faith in you.”

Yuichiro nodded. “Right, I will. In the meantime, you’ll watch over Muichiro for me, right?” He looked at the futon where his brother rested peacefully.

“Of course, we’ll keep him safe while you’re gone.”

“Right. Then, I guess I’m off.” He’d have to leave soon if he wanted to make it to the mountain by nightfall. He walked past Amane, who spoke once more.

“Good luck… though I doubt you’ll need luck.” Something in her tone caused Yuichiro to look back. The smile on her face was knowing and almost… mischievous. “You’ve already proven your skills, after all.”

“I… don’t know what you’re talking about,” he tried to sound nonchalant, but really he just sounded even more guilty.

Amane chuckled. “There’s no need to hide it; we’re not mad. The crows told us about what happened that night. The Master was quite impressed, you know. With you and Muichiro.”

Then, they already knew about Muichiro’s Blood Demon Art? But if they hadn’t said or done anything yet, then surely it was nothing to worry about? Still, Yuichiro felt embarrassed, both because they’d been caught, and because he thought they’d gotten away with it. He bowed his head in shame. “…Sorry, Miss Amane.”

Amane shook her head. “I believe I’ve kept you long enough. Please, be safe, Yuichiro.”

Yuichiro smiled and nodded. With one more glance at the sleeping Muichiro, he departed.

The hours of travel it took to reach the mountain in the distance were long and lonely. It felt weird to be walking around outside without the weight of Muichiro’s basket on his back and shoulders. It was too quiet, and Yuichiro couldn’t stop thinking about his brother. Was he doing okay without him? Was he as lonely as he felt now? His footsteps hurried, almost desperate to reach the mountain and get this stupid Final Selection over with.

He made it to Mount Fujikasane just as the setting sun was painting the sky shades of orange. Wisteria trees literally covered every space of ground here, almost to the point of overwhelming his eyes and nose. But he quickly made his way to the mountain’s checkpoint, where all the prospective demon slayers were to gather. About fourteen people were already here, as well as two of the Master’s children, the boy Kiriya and one of his sisters, Kuina.

Yuichiro scanned the other potential slayers with disinterest. Some looked confident, others nervous, and at least one girl in pigtails looked scared out of her mind. He knew full well that not all of them would be getting through these next seven days alive. He also didn’t miss how several gazes lingered on him, likely because of how young he was. But he couldn’t spare them much thought; he had to focus on his own survival, so he could make it back to Muichiro.

He waited and watched as Kiriya and his sister introduced the Final Selection and what they would have to do to survive. It wasn’t anything he hadn’t heard already, but he listened anyway. Anything to make sure he made it back alive.

“Now, your trial begins.”

—

That same night, a white mist slipped out of the Ubuyashiki Estate and into the clean air. It swept over the garden, covering everything from the grass to the trees. And at the same time, a small shape moved through the fog and towards the wall. It leapt the wall with ease and sprinted into the forest.

The mist consuming the garden pulled back, returning to its owner deep in the woods. With no watching eyes on him, Mui set his sight on the mountain in the distance and took off running.

—

“Mist Breathing, Second Form: Eight Layered Mist!”

His blade struck out eight times in a matter of seconds, shredding the demon’s limbs and taking off its head. Yuichiro didn’t stop to watch it disintegrate as he took off, eyes set towards the east side of the mountain. If he could reach where the sun rose first, that would reduce the overall danger to him over these next seven nights.

The demons he’d encountered so far weren’t like the one he and Muichiro had faced in the forest. They were weaker, slower, and didn’t seem to have any Blood Demon Arts. Muichiro himself moved and attacked faster during their mock battles. But that was no excuse to let his guard down; who knew what else could be lurking on this mountain?

A growl from his right caught his attention, and he stopped running to survey the area. He quickly spotted the demon, back turned to him as it searched for something around the trees. Yuichiro thought for a moment; he could likely sneak past it easily. Then again, one less demon on the mountain now was one less threat later on. His mind made up, the demon didn’t even see it coming before his sword slashed through its neck.

Yuichiro turned to go when a choked whimper stopped him. Looking around, he spotted what the demon had been after; another candidate curled in a gap between the tree roots.

“Hey, are you okay?” Upon closer inspection, he realized it was the girl in pigtails, decorated with blue butterfly hair clips. She seemed familiar, actually. Had he met her somewhere before this?

The girl flinched and looked up at him with teary, terrified eyes. Seeing that he wasn’t a demon, however, she calmed down enough to speak. “T-The demon, is it gone?”

Yuichiro nodded. His eyes narrowed. “Why were you hiding from such a weak demon?”

The girl grit her teeth, seemingly offended, but then she looked away, too embarrassed to answer. Yuichiro sighed. “Well, anyway, I’m heading east, so you should too. Good luck-”

“Wait!” The girl’s hand tightly gripped his own. “I… I don’t have my sword! I lost it when that demon attacked me!”

“…Seriously?” Yuichiro rolled his eyes. “Can’t you just go look for it?”

“Not in this darkness!” He supposed she had a point there. “Please, don’t leave! You’re the first person I’ve come across, and… and you saved me!”

“I was just getting rid of a threat. I didn’t even know you were there.”

“E-Even so! Just, don’t leave me here alone!”

What a pain in the... Yuichiro relented and turned back. “Fine. But stick close to me, okay? And don’t get in my way.”

The girl nodded, looking relieved. “I’m… I’m Aoi Kanzaki.”

“Yuichiro Tokito.”

“Tokito… Wait, are you the boy whose brother is a demon?!” Yuichiro nodded. “Wow… And you’re here? But you’re so young, and… shorter than me.”

Yuichiro’s eye twitched. “Why does that matter?!” he snapped. He didn’t need to be reminded of how short he was. And anyway, he was only twelve! He was still growing!

Aoi blushed. “Y-You’re right! I’m sorry!”

Yuichiro sighed and decided to let it be. “…You seem familiar. Have we met?”

“Um, maybe? I live at the Butterfly Estate, so you might have seen me there.”

Ah, that explained it. He and his brother had been over there a couple times for checkups. “Right, I remember now. Anyway, Kanzaki, we need to-”

A human scream filled the air, followed by an overwhelming sense of danger. Yuichiro felt it from here, a presence that had his every hair standing on end. He grabbed Aoi’s hand and pulled them both into the gap between the tree roots. “Hide!”

“Wha-!” His hand slapped over her mouth to cut off any further noise. He heard the human run past the tree, breathing frantically, his fear palpable. Yuichiro remained still as he looked down at the ground. The pebbles at his feet trembled rhythmically, growing stronger and stronger each time. Footsteps. Something was coming.

He could feel Aoi shivering beside him; this hiding spot was a tight fit for two people, so they were pressed pretty close together. Perhaps he might have even been embarrassed to be so close to a girl, if the situation weren’t so dire.

The stomping was even louder now; it felt like whatever was making that noise was right on top of them. Yuichiro chanced a peak around the tree, and regretted it instantly. An absolutely enormous, fleshy thing, covered in arms - was this a demon?! It’s size and presence was overwhelming, far greater than the other demons on the mountain. Why was something like that wandering here?! There was no way they could be expected to fight it!

…Unless, they weren’t supposed to? Maybe this was a test too, to gauge the opponent’s strength and to know when they were outmatched and were better off hiding or fleeing. That made sense; the Final Selection was all about survival, after all.

Yuichiro retreated back into his and Aoi’s hiding spot and shook his head, placing a finger over his closed lips. Aoi nodded in understanding, and they simply waited as the giant demon passed them by. It paid them no notice, seemingly fixated on the other human that had fled past. Eventually its footsteps grew quieter, receding into the distance, but it was only when they were sure that it was gone did they leave the shelter of the tree roots.

Yuichiro took Aoi’s hand to help her up. He briefly wondered about that other person, and if they had gotten away. But ultimately it wasn’t his concern; he could only worry about what was in front of him right now. “Let’s go, before anything else like that shows up.”

Aoi nodded, and they resumed their desperate dash towards the east.

—

Time marched on, the sun rising and setting on Mount Fujikasane, day after day. Yuichiro and Aoi stayed together; without a sword, Yuichiro knew she was as good as dead if he ever left her alone. He did most - no, he did all of the work between them, cutting down any demons that crossed their path. He did so quickly and efficiently; Aoi seemed in awe of his skill, but Yuichiro thought she was overselling him. Any slayer with a sword should be able to do what he was doing.

Then on the third night, they came across their first human body. They heard ripping and chewing, and found a demon feasting on one of the other candidates. Yuichiro cut it down, but there was obviously no saving the boy. His corpse was so bloodied and torn apart as to be almost unrecognizable. Not that he would know him in the first place, but a dead body was still a horrific sight. Aoi had nearly thrown up, and even Yuichiro had to stop and think about what he was really doing here.

That could be me. I could end up just like that. A meal for a hungry monster. An unnamed casualty in an unknown war. A completely pointless death.

But then he snapped out of it and shook his head. No, that wouldn’t happen. Because he had to get back, had to make it out alive. For Muichiro.

He took the dead boy’s sword and tossed it to Aoi, who fumbled with the blood-slicked sheath. Maybe he should have cleaned it first. “Come on, we need to keep moving.”

Over the next few nights, they found more demons, and more would-be slayers who didn’t survive. Even with a sword, Aoi still wasn’t much help in fighting, but that was fine; Yuichiro could handle these low-level fodder easily. He couldn’t understand how so many people had died to these things. Weren’t they trained specifically to kill them? If someone like him could survive here, they should’ve been able to as well. Maybe they’d run afoul of that powerful demon he’d seen the first night? But he hadn’t seen a single sign of that demon since then.

Aoi was too scared to fight, but she made up for it in other ways, such as finding and identifying medicinal herbs and plants that were safe to eat. It helped stretch their rations out and keep their strength up as time went on. And while Yuichiro wouldn’t admit it, she did make for decent company. He’d never really been alone before; he’d always had his twin, and this was the first time they’d even been truly separated. They didn’t talk much, too focused on survival at night and too tired during the day, but just having someone else by his side made this hellish experience more bearable.

On the eve of the seventh and final night, Yuichiro and Aoi waited in their makeshift campsite for the sun to set.

“Just one more night,” Aoi breathed and wrung her hands together anxiously. “Then this’ll be over.”

Yuichiro nodded. “I wonder how many other candidates are still alive?”

Aoi flinched. “Well, we’ve come across seven bodies so far, and I think there were fifteen of us in total…”

“Tch, this is disgusting. Who sends children into a monster-filled death trap like this?” None of the bodies they found had been any older than teenagers; it made Yuichiro sick to his stomach.

“Well… you’re here, aren’t you? You’re younger than any of us.”

Yuichiro rolled his eyes. “I’m here because I have to be.”

“You mean, for your brother?”

He nodded. “I need to slay powerful demons if I want any hope of making him human again. So I have to become a demon slayer. That’s all there is to it.”

Aoi hummed. “What’s he like, your brother? You must get along well, right?”

“I’d like to think we do now, but we didn’t always. Things were hard for the two of us, even before he became a demon. I wasn’t as good to him as I should’ve been.”

No, if he was being honest with himself, he wasn’t just not good, he was downright awful to Muichiro. It was all for the sake of keeping him safe, from getting himself killed by his own kindness, but there was no denying he’d been cruel. He often wondered how much of it Muichiro even recalled as a demon, but even if he had forgotten, Yuichiro himself still remembered.

“As for what he’s like, we’l, he’s scatterbrained, irresponsible, and naive to the point of stupidity sometimes.” As he spoke, the scowl on his face turned into a nostalgic smile. “But he’s also the nicest and most cheerful kid you’ll ever meet. And that hasn’t changed, even after becoming a demon. He’s quieter, sure, and he’s harder to read, but he’s still just as kind. That’s why he has to eat demons, because he refuses to even touch a human.”

Aoi seemed in awe as he finished speaking. “Huh, that’s not at all like what I’ve heard around the estate,” she mused with a hand on her chin. “Not that I put much stock in those rumors, anyway.”

“Rumors?” Yuichiro suddenly felt on edge. “What rumors?”

“Uh, never mind! Forget I-”

“No, tell me! What rumors?! They’re about Muichiro, right? What are they saying about him?!” Yuichiro refused to let this topic drop until he got his answers.

Aoi flinched and backed away from him. Yuichiro realized he was getting too worked up and tried to rein in his growing panic. “…Sorry, just… please tell me.”

“…Look, obviously there are gonna be some people who won’t trust a demon in the Corps, even with the Master’s blessing. I don’t know who started them, but they’ve really gotten around. Things like you’re being possessed by your brother, or that you two are alone because he ate your parents. Crazy stuff like that.”

“Ate our…?! That’s total crap! None of that is true!” Yuichiro shouted, horrified at the idea that complete strangers could actually be saying that about his twin. How many of them actually believed that? And what if Muichiro found out about these rumors? He’d be devastated!

“I know that! I knew they couldn't be true; the Master would never allow an evil demon like that into the Corps.”

“Of course not! Mui’s not…” He was definitely getting worked up again. Yelling at Aoi was not going to do anything about these disturbing rumors spreading around. But what could he do about them, if they had spread to such an extent? The thought of Muichiro hearing those things made him feel ill.

“Sorry, I shouldn’t have said anything,” Aoi grimaced.

“It’s… fine.” It really wasn’t, but it was better he found out like this than the alternative. He tried to think of how he could keep this a secret from his twin. “Thank you for telling me.”

“Like I said, I don’t believe in those rumors, especially after what you told me. But there are people who do, so… be careful, okay?”

Yuichiro scoffed. As if he’d let anyone antagonize him or his brother. He’d cut them to pieces if they tried.

Aoi went silent after that. This time, desperate to get off that foreboding topic, Yuichiro asked a question. “So what about you? Why are you here?”

“Me? I…” Aoi drew her legs up to her chest and wrapped her arms around them. “…My family is gone. Because of demons. The Butterfly Estate took me in, so…”

“So you feel indebted to them? Because they took you in when you had nothing?” Yuichiro guessed. Aoi nodded, and he let out a huff. “Don’t feel like you have to risk your life to repay someone’s kindness. I’m sure Shinobu and the others at the Butterfly Estate wouldn’t want that either. They’d want you to live above all else.”

Aoi didn’t say anything, but he saw tears in her eyes. Her brow was furrowed and she looked deep in thought. Yuichiro sighed and stood up. “Let’s get going, it’s just one more night. We should start making our way back towards the wisteria trees.”

As Aoi stood up to follow, Yuichiro looked towards the last rays of the setting sun.

Hold on just a little longer, Muichiro. I’ll be coming back soon.

—

The hours passed, and Inevitably, the sun rose on the seventh day. The Final Selection came to an end. Yuichiro and Aoi made their way back to the midpoint where the survivors were ordered to gather, but when they did…

“Y-You’re kidding! We’re the only ones who came back?!” Aoi gasped. She was visibly shaking. Yuichiro didn’t say anything, but he was shocked too. Out of fifteen candidates, only two survived? And if he hadn’t agreed to protect Aoi, well, without a sword…

He reached over and grabbed Aoi’s trembling hand. The girl’s eyes snapped towards him, and suddenly Yuichiro felt very awkward. “…Just, don’t think about it. You couldn’t have changed anything. What matters is that you survived. You can go home.”

They could both go home, but for Yuichiro, home was where his brother was. He let go of Aoi’s hand and went first to choose the ore that would make up his new nichirin sword. Once he did, he stood aside to wait for Aoi, but she stayed where she was, hands wringing together nervously.

“Please choose a nichirin ore, Miss Kanzaki,” Kuina instructed her.

“I… I’m sorry! I can’t!” Aoi cried suddenly, bowing her head. “I didn’t survive on my own; I was protected the whole time! I even lost my sword! I’m not worthy to be a demon slayer!”

“Then what will you do instead?” Kiriya asked. There was no judgment in his tone, only curiosity.

“I… don’t know…”

Yuichiro huffed and walked up to her. “Hey, don’t beat yourself up for it. Not everyone can risk their lives to save people. Only the chosen ones can do that. If you force yourself, you’ll just put yourself and other people in danger. But if you still want to help, I’m sure there are other ways you can do that, right?”

Aoi seemed confused. “Huh? Chosen ones? You mean like you?”

Yuichiro shook his head. “I’m not a chosen one; I’m just trying to protect my brother. He’s the real… Nevermind.”

Aoi stared at him with a strange, almost pitying expression that made Yuichiro uncomfortable. He turned away as a caw came from overhead and a crow fluttered down. Kiriya told him it was his assigned Kasugai crow, and he let it perch on his hand. Why did it have eyelashes, though?

“...Anyway, I’m heading back now. Mui’s waiting for me. You can do whatever you want.” He told Aoi with a shrug and let the crow fly away before turning to leave. He almost made it to the stairs when Aoi called out to him again.

“Wait, Tokito! You say that, but… but you protected me! If it wasn’t for you, I wouldn’t be here! So… thank you for saving me!”

Yuichiro froze, eyes going wide. He felt a surge of emotion, though what kind he wasn’t sure. Happiness? Anger? Both? Whatever it was, he shoved it down and kept walking.

It had been a long seven nights. Seven nights of fighting for his life, of brushing against the jaws of death and witnessing those who were too weak to avoid it. He didn’t want to think about Aoi’s words and what they evoked in him.

“…You’re welcome.”

All he wanted now was to get back to Muichiro.

Chapter Text

The first night of Final Selection…

He could do this.

Just breathe. Breathe in as deeply and fully as you can-

His muscles locked up, and Mui doubled over, hacking, agonized coughs ravaging his lungs. Specks of blood dotted the ground, but they soon stopped, along with the pain. He hung his head and sighed; yet another failed attempt at Total Concentration Breathing.

Mui looked up at the wisteria trees that barred his way further up the mountain. The smell was repulsive and he felt sick to his stomach just looking at the purple flowers, but he couldn’t leave. Yui would be up on the mountain for another six nights, and Mui wanted to be here for him when he came back down.

But, that didn’t mean he couldn’t at least go for a walk. Maybe getting away from the nauseating wisteria for a bit would help somehow. The forest was quiet as he walked along, lost in his thoughts. How was he supposed to become a demon slayer like Yui if he couldn’t master Total Concentration Breathing? The constant failures were starting to weigh on his mind, affecting his focus and making his next attempts even more fruitless, a vicious cycle he couldn’t get out of. Mui groaned and sat down against a tree, claws digging anxious gashes in the dirt.

Was it hopeless after all, for a demon to use Breathing? He wished there was someone out there who could tell him what he was doing wrong. But no such person appeared. In fact, the forest felt unnaturally quiet and empty. Mui stayed away from the main path to avoid the gazes of the Kasugai crows, but he couldn’t even sense them now.

He sniffed the air, and something caught his attention: a faint, metallic smell. It hadn’t been there when he first sat down; how lost in thought had he been? But the smell was unmistakable. Blood, but not the blood of a human. This was weaker and barely enticing to his nose. The blood of an animal.

Curious, he stood up and followed the scent. It only took him a few minutes to find the source: a crow, lying on the ground in a mess of bloodied feathers. He picked up the dead bird, its body still faintly warm. He stretched out the wings to examine it, and found a long gash across its right side, almost severing the wing on that side entirely. The cut was long and clean; a sword, maybe?

Was this one of the Kasugai crows? There was a familiar scent to it underneath the blood, so it must be. But what had killed it? It wasn’t an animal; it hadn’t even been eaten, just slain and left here. But a demon’s claws wouldn’t leave a wound this clean, either.

Mui looked around, but he didn’t see or sense anything. Still on alert, he dropped to the ground and dug a shallow grave in the earth with his claws, then placed the crow inside. He didn’t know any prayers, so he covered it up and bowed his head, before quickly returning to the spot where he’d left his basket to wait for Yui. Though this time, Mui took the basket and moved it just a little ways further from the wisteria. He didn’t think the poisonous plant was doing his Breathing attempts any good.

Mui remembered what Yui had said about his breathing, how his lungs were regenerating and stopping him from getting stronger. He sat, facing away from the wisteria, and tried again. He breathed in as hard and fully as he could, and when the expected pain came, he focused on willing his lungs not to heal.

He coughed, the taste of his own blood on his tongue. Don’t heal. Don’t heal. Remember the pain. Adapt to the pain.

“What… are you doing?”

Mui froze, all thoughts of Total Concentration Breathing forgotten. A deep, intimidating voice, right in front of him. A familiar voice.

He looked up, eyes wide. Wild black hair like a lion’s mane, tied in a ponytail. A purple and black kimono. And six yellow eyes.

Upper Moon One gazed down at him. “You are… practicing Total Concentration Breathing?”

Mui stared. Normally the sight of a demon would cause a fire to rage through his veins, spurring him into a frenzy. But this demon was different. He couldn’t muster any anger, only fear and… awe. He couldn’t look away from the demon’s imposing, majestic figure as he slowly nodded, compelled to answer.

Upper One’s six eyes narrowed in thought. “I see… you are… on the right track. But… stopping your regeneration alone… is not enough.”

Mui tilted his head. How would he know that? Then he managed to wretch his eyes away from the Upper Moon’s face to look at the sword at his hip. A sword… he pointed at it. “You… killed crow?”

The Upper Moon said nothing. Mui wondered if that was an admission of guilt. He did the same thing, whenever he did something bad. But he wasn’t like Yui; he didn’t try to force an answer. “…Swordsman?”

The Upper One nodded. “I was a swordsman… before I became a demon. And I can teach you… Total Concentration Breathing…if you wish to learn.”

Mui gasped; for a second, his heart jumped with joy. He could finally learn Total Concentration Breathing! He could become a demon slayer like Yui! But then he stopped and wondered. Upper Moon One had turned him into a demon, right? He was like this because of him. “…Why?”

“Why…” The Upper Moon fell silent, looking thoughtful. “You have… potential… as a swordsman. And as a demon… you can grow stronger... than any human.”

Mui frowned. He didn’t think he wanted that. He didn’t want to be stronger than his brother; he wanted to be human so he and Yui could be swordsmen together. But until he was human again, he needed more strength. He needed to be able to protect Yui.

“I… want to learn.” Mui decided.

Upper One nodded. Mui couldn’t tell if he was pleased or not; his expression was unreadable. “Good. Then I will train you…”

The Upper Moon led him to a wide open space away from the main path where it was unlikely they’d be disturbed. Mui and Upper Moon One stood across from each other, a few feet separating them as the demon pulled his sword from his sheathe. The fleshy look of the sword and the numerous eyes along its blade unnerved Mui, but he kept his face passive, not wanting to offend his new teacher.

Upper One seemed to think for a moment before another, smaller sword suddenly sprouted from his hand. He held it out to Mui. “Take this… I wish to test… your skills with the sword.”

Mui really didn’t want to touch the sword; even the hilt looked fleshy. Then an idea hit him, and he gasped in delight. He held his arm up and as mist poured out of his sleeve, he willed it to gather in front of him. The clouds collected into a long, thin shape, and when he closed his hand around it, it felt solid. He held his new mist sword up proudly.

Unfortunately, his teacher seemed skeptical about the idea. “I… do not think that will work… for this purpose.”

Mui scowled and let the sword dissipate. He crossed his arms and pouted while the older demon sunk the flesh sword blade-first into the ground in front of him. Thankfully, there were no eyes on the hilt, so he reluctantly picked up the weapon.

Upper One then took a defensive stance. “Now… attack me. Do not be afraid… to use all of your power.”

Mui nodded, then took a stance and shot forward. Mist surrounded him as he struck out with the first form, but the Upper Moon blocked it easily. Mui stepped back and tried to attack from another angle, but the demon stopped that attack, too. So did it go for a long time, Mui trying to land a hit as Upper One blocked each and every strike without a single one of his own. That is, until the end.

“Moon Breathing, First Form: Dark Moon, Evening Palace.”

The demon unsheathed his sword for but a second, and suddenly Mui’s sword arm was slashed off below the shoulder. But the younger demon barely noticed, captivated by the beautiful crescents that sprang from the blade, illuminating the night. HIs own eyes lit up, excitement rising within him.

“Amazing,” he gasped, bouncing up and down. “Again! Again! Show me again!”

The Upper Moon stared impassively down at him.

“Your regeneration… is quite slow. Have you not eaten… a single human?”

Mui stopped and stared at his severed arm for a few seconds, watching the blood drip. Then he shook his head vehemently. “Only eat demons!”

“Is that so…? You are… quite unusual.” The Upper Moon seemed deep in thought, silent for several seconds. “Nevertheless… you are quite skilled… for having only recently… picked up the sword.”

Mui didn’t show it, but on the inside, he glowed from the praise.

“However… without Breathing… you can only go so far. I will teach you… Total Concentration Breathing. But be aware… it will not be easy… as one who became a demon… before learning breaths."

And who was the one who transformed him before he could learn? Mui crossed his arms and glared. “That’s your fault.”

Upper One blinked. “…Yes, I suppose… it is. You have… my apologies.”

Mui nodded, satisfied for now. Then his eyes lit up again as he remembered. “Moon Breathing! Show me again!”

The demon closed his eyes and hummed. “If you… follow my instructions… and show improvement in your training… then I will show you more forms.”

Mui nodded and forced himself to stand still and attentive.

“Now… understand that a demon’s potential to adapt… is almost limitless. Our wills… can shape the growth of our bodies… Thus, to learn Breathing… you must will your body to learn… as a human would.”

Mui tilted his head in confusion. Is this what he meant, then, when he said he was on the right track by forcing his lungs not to regenerate? “So, don’t heal?”

“To an extent… will your lungs… your body… to heal stronger. With your slower regeneration, perhaps… it will come to you more easily… than most.”

“You tried before?” Mui asked. “To teach Breathing?”

“I have… All have ended in failure…” the Upper Moon looked frustrated as he admitted this. “I hope that… you will be the first to succeed.”

Mui nodded, a newfound determination building up in him. He would succeed, for Yui and for his teacher.

“The sun… will rise soon.” Upper Moon One said, looking to the lightening sky. “I will return… tomorrow night.”

Mui smiled. And he would be here, waiting.

--

True to his promise, Upper Moon One came back the next night. Mui could barely contain his excitement when he saw the older demon’s approach, jumping out of his basket to greet him under the moonlight.

“Teacher! You’re here!”

“Teacher…” the demon cocked his head, six eyes blinking slowly. Mui tried to mimic it with his own two eyes. “Yes… very well. Let us continue…”

And so passed the night, as Mui tried to put his Teacher’s instructions into practice. To control his regeneration, Teacher would cut off a limb and then challenge him to regenerate it consciously, willing it to regrow into a stronger form. That part turned out to be pretty easy, as he could just imagine Yui’s older, more honed body as the goal for his own. And Breathing was getting easier as well; his earlier doubts cleared away, he simply willed his lungs to become stronger and able to take in more air. Such a simple solution, though hard to pull off in execution.

On the third night, Teacher did not present him with a sword. Instead, he asked, “Have you developed… a Blood Demon Art?”

Mui nodded eagerly, then allowed his body to disperse into a mist that flooded their little training grounds. Teacher stood amongst the white haze, a hand on his chin, as he quietly observed.

“Hmm… so you can deconstruct your body… to form a mist to obscure sight. How long… can you maintain it?” Mui shrugged (or tried to, since he didn’t currently have a body) and let his misty form hang around the Upper Moon. After about a minute, the demon grunted and held out his hand.

“Curious… this mist appears to… dissolve the cells of living beings…” he thought aloud.

Muichiro materialized his upper body in front of the Moon. “Not living beings,” he corrected, “Only demons!”

“Is that what you think?” Teacher asked, still looking at his hand. “It seems that… you do not fully understand… your own abilities. Not to mention… it is very slow… and not effective for combat.”

Mui frowned and stuck out his tongue. His mist could eat faster if he wanted it to. Quietly, he retreated into the fog and tried to do just that, but the demon’s cells regenerated so quickly that he might as well be doing nothing at all. Once again he was in awe of his Teacher’s power.

“Attack me,” the Upper Moon instructed suddenly. Mui grunted and his mist circled the demon, looking for an opening. He reformed his upper body again, behind the Upper Moon, and struck out.

Teacher turned and his sword went through Mui’s chest. Mui bit his tongue to keep from crying out, and his body exploded back into mist to escape. Teacher sheathed his sword and hummed. “As I expected… you need to reform your body… to attack. It leaves you vulnerable… if only for a moment. You must move… and act faster… to shorten that moment.”

Mui reformed his top half again before the Moon and nodded in understanding. “Now… again.”

By the end of the night, Mui could still feel the phantom pain of that sword stabbing into him again and again. But he was determined to push through it, to get stronger and faster so he could help Yui once he became an official demon slayer.

The fourth and fifth nights proceeded in much the same manner. Teacher was very strict, always correcting the slightest mistake in his breathing or his forms. When they sparred, he’d go on the offensive more often, which always left Mui with a severed limb, even when he used his Blood Demon Art. But Mui also knew that Teacher was holding back his true strength. Because he wanted Mui to learn and get stronger. So he put his all into his training, determined to meet the expectations of both his Teacher and himself.

Each night, his fights with Teacher proved he was getting better. His movements and sword strikes were even faster, had even more force behind them. While he still never managed to land a hit on his Teacher, the older demon praised his improvement nonetheless.

On the sixth night, he finally allowed Mui to fight using his mist sword. He learned that by condensing the particles enough, he could achieve a semisolid state strong enough to cut through solid matter like wood. Unfortunately, it still didn’t make for a good training weapon, due to lacking the weight and feel of a proper sword. But it worked, and Mui didn’t think he’d ever forget the look on Teacher’s face when he cut through a tree with it for the first time.

And each night, before the sun rose, Teacher would show off one of those beautiful Moon Breathing forms. First form, second form, third, fourth, fifth, sixth; each more impressive than the last. Mui watched with rapt attention, imprinting the forms and the movements of his teacher into his mind. He would not allow himself to forget them.

Mui found that he was really enjoying his time with the older demon. There was something familiar and almost comforting about him that he couldn’t quite place. But all good things came to an end.

“That is… enough,” On the seventh night of the Final Selection, Teacher laid to rest his sword and sat on the ground. Mui followed, choosing to sit right next to him. The Upper Moon gave him an unreadable look, but he didn’t protest or tell him to move.

“The sun will rise soon… and your brother will return. This marks the end… of our training.”

“Do good?” Mui asked with a small smile.

“You have… surpassed my expectations. But do not… let that make you… complacent. Continue your training… every day.”

“Okay!” Mui exclaimed, pumping his fists. “Gonna get even stronger! For Yui! And for Teacher!”

The Upper Rank demon stared at him, his expression still unreadable, then gave a single nod. “Good. Remember this… Demons… do not age. They do not weaken. They can grow… infinitely stronger. Master your Breathing… Master your Blood Demon Art… And none… will stand before you.”

The seriousness of his words and tone gave Mui pause. Why say something like that? He didn’t want to get stronger just for the sake of it; he wanted to get stronger to protect what he cared about. Though, he doubted Teacher needed any protection.

The Upper Moon stood up and placed a hand on Mui’s head, a gesture that caused him to look up with eyes stretched wide. Then he stepped away, and Mui’s hands flew to his hair as he continued to stare.

“…I look forward… to seeing your growth… my student.” And then he was gone, leaving Mui alone and still in disbelief that the last few seconds had really happened.

Then he noticed the sky turning pink, and an instinctive jolt of panic ran through him. He had to get back to where Yui would be coming down before the sun rose! So without any further thought on his Teacher, Mui raced away into the shade, heading back towards the wisteria trees. He made it just in time, diving into his basket and sealing the lid before the sun’s rays touched the ground. Sunlight surrounded him, pinning him within what meager shade was provided by the tree his basket rested against. Mui settled down and waited…

And waited…

Until he heard something. Footsteps against stone, descending the mountain and coming closer. The footsteps stopped briefly, and he heard a deep sigh. It was Yui!

“Hey, Mui-” He was right next to him. Mui didn’t wait for him to finish as he burst from the basket.

“Yui!” he shouted, tackling his brother in a bone crushing hug. For a second, they stumbled back towards the sun, but Yui managed to regain his footing.

“What are you doing out of the basket, idiot?!” he yelled. “It’s morning!”

Muichiro let go and stepped back a safe distance into the shade. “Waiting! For you!”

“Yeah, I see- what the hell happened to your clothes?!”

Mui blinked and looked down at himself. It was only then that he noticed the large amounts of cuts, tears, and blood staining his clothing. Remnants of his lessons over the past seven days. He couldn’t regenerate his clothes, after all. He wondered if it was possible to fix that.

Wait, worry about that later. Yui was still waiting for an answer.

“…Training."

Yui scoffed. “With what, a bear?”

Mui didn’t say anything, instead opting to give an awkward smile. After a while, Yui gave up waiting and changed the subject.

“You’ve really been waiting here all this time?” Mui nodded, and his twin crossed his arms with a scowl. “That must’ve been boring.”

Mui shook his head. “No! I had Teacher!”

In hindsight, he’d been too excited, too happy to see his brother again, that he didn’t even think to filter himself. He didn’t even think to lie about what he’d been doing.

“Teacher?” Yui repeated.

“Yeah! Teacher! Teaching me Total Conch… conce… con-” He struggled, fangs getting in the way of his tongue’s movements. So embarrassing; he felt his face heat up.

“Okay, don’t hurt yourself, I know what you mean.” Yui stopped him. “So who’s this Teacher teaching you Total Concentration Breathing?”

“Teacher is…” Mui trailed off. It suddenly hit him that he might have made a mistake. He’d had seven days to get used to training with Upper Moon One, but this would be Yui’s first time hearing of it. Not to mention the glaring fact that Upper One was supposed to be the enemy. Yui's eyes narrowed, his impatience starting to show the longer he went without speaking. “Teacher is... Teacher.”

“That’s not an answer, Muichiro! What are you hiding?” Yui shouted suddenly. Mui reeled back; it’d been a long time since Yui had yelled at him. His nervousness was becoming obvious as he fidgeted in place.

“…Won’t get mad?”

Yui groaned and rolled his eyes. “I won’t get mad.”

Ironically, that didn’t give Mui more confidence to speak up. “Won’t hate me?”

Yui looked worried now. “…Mui, you’re my twin brother. I could never hate you. You know that… right?”

Did he? Yui said that now, but once he found out- Mui forced the thought down and nodded frantically. He trusted his brother. Slowly, he raised his hands to his face and placed two fingers over his forehead and two more across his cheeks. “Six… eyes.”

“Six-!” The horror on Yui’s face was instant and unmistakable. “What?! You mean your teacher is Upper Moon One?!”

Mui flinched and hid his face behind his kimono sleeves. His twin’s voice made it obvious he was angry, even if he said he wouldn’t be. Of course he would be angry. He should’ve known Yui would react like this. He should’ve kept his mouth shut.

“You can’t honestly be this stupid! Did turning into a demon damage your brain or something?!” Mui winced; that was mean. “That’s Upper Moon One! The second most powerful demon of them all! That guy’s bad news through and through!”

Mui lowered his sleeves, a guilty look on his face. “Teacher… offered to help. He is strict but… nice.”

“Nice? Mui, that’s the guy who turned you into a man-eating demon in the first place! Who cares how nice he is? He’s obviously trying to trick you into lowering your guard for some plan of his!"

For some reason, Yui’s words sounded familiar to him. Like he’d heard these words before, in a different situation. As Yui continued to yell, Mui felt something building inside him. It wasn’t the fire, the rage that drove him to fight against demons. This was something else. A cold, sludge-like feeling that clung to his insides and wouldn’t let go. It started in his stomach and pooled up, rising higher and higher. Unknowingly, he clenched his fists and glared at the ground.

Why did Yui have to act like this? So what if he was his big brother? Mui wasn’t some dumb, weak kid anymore. He was a demon now; he could regrow his limbs and heal from any injury. He could handle himself. Teacher was never a threat to him; if anything, he helped him in a way that no human could. Why didn’t Yui understand that? Why was he treating him like something that needed protecting from the world? When they were supposed to be equals?

Was it because they weren’t equals after all? In the end, Yui was a human, and Mui wasn’t. That’s why Breathing was so easy for him, when Mui had to work so hard at it, to resort to getting help from Upper Moon One. They weren’t equals at all.

Suddenly, he didn’t have the energy to be angry. His fists unclenched and his head slumped, defeated. To himself, he whispered, “Just… wanted to be like you.”

—

"Just… wanted to be like you."

“Huh?” Yuichiro wasn’t sure he had heard him right. He stepped closer.

“Wanted to… use Breathing… like you.”

Yuichiro didn’t know what to say. He exhaled, his anger fading away. Muichiro was so skilled at the Mist Breathing forms, at fighting in general. He almost always won their spars even without his demon strength. Yuichiro envied that natural skill. But he never once considered that Muichiro might envy him for being able to use Total Concentration Breathing.

He thought he could read his twin’s hidden emotions better than anyone, but to miss something so obvious… He really was a terrible older brother.

“I’m… sorry,” Muichiro said with tears in his eyes. “Was stupid…”

“No, I’m sorry,” Yuichiro shook his head. “I shouldn’t have gotten so upset. Is that really all you did? Just train?” His brother nodded. “Then, I guess you didn’t really do anything bad. But, Mui, please don’t talk to that man ever again, okay? You absolutely can’t trust him! Understand?”

“Yeah… Understand,” Muichiro gave a tiny, relieved smile.

“Hey, Tokito!”

Yuichiro turned to see Aoi descending down the mountain steps. He didn't feel like they were done talking about this, but they couldn't say anything more about it now. The pigtailed girl froze briefly at the sight of Muichiro, but recovered quickly upon realizing who he was. “Hey Kanzaki. Heading home?”

“Yeah, I am. I’m surprised you’re still here. And with…” she peeked around him to get a better look at Muichiro who smiled and waved. "...What happened to his clothes?"

“Training with bears, apparently," Yuichiro lied nonchalantly. "And we were just about to leave. Right, Mui?” His brother nodded and went to get back into his basket, leaving Yuichiro and Aoi to stand awkwardly beside each other.

“Um… do you wanna walk together part of the way?”

Yuichiro shrugged. He would have appreciated the alone time with Muichiro, but it’d be rude to refuse. They had spent the last seven nights fighting for their lives together, after all. “Sure.”

The walk back with Aoi proved to be a good distraction, but once they parted ways, he was left with only his thoughts. He couldn’t stop thinking about how his brother had spent all this time training with Upper Moon One. What kind of things was he teaching him? What was he planning? He had no idea, and that terrified him.

The two of them returned home to Amane waiting patiently at the gate. And in that one moment, exhausted, homesick, and plagued with worries, Yuichiro had never been more happy to see her. He ran the rest of the distance between them and practically leapt into her arms. He gripped her tightly, as if she might disappear from his life just as his mother and father had if he let go.

“Welcome back,” Amane said, softly and kindly. Just like…

Yuichiro rested his head against her chest. If Amane noticed the tears trailing down his face and dampening her kimono, she didn’t say anything. She just held him gently and allowed him the warmth and comfort he needed. He was still only a child, after all.

A child who was now a demon slayer, and whose struggles had only just begun.

Chapter Text

If Yuichiro were asked to describe his life after becoming an official demon slayer in one word, it would be busy. Two weeks after Final Selection, his assigned swordsmith, an old man named Tetsuido, presented him his newly forged sword, which had turned a brilliant white in his hands. At the same time, Amane had also given him his Demon Slayer Corps uniform and a special gift: a haori made of the same misty fabric pattern as his old yukata. From there, it was nonstop work; despite only two more weeks passing since then, there wasn’t a day he wasn’t traveling between locations, hunting down demons and moving onto his next mission as his crow instructed him. And of course, Muichiro came along every time.

Their first official mission was nothing to note. The demon had underestimated him, taking him to be just a kid, and its head had rolled one strike later. Those after fell just as easily; any that evaded his first swing would find themselves at the end of Muichiro’s claws, and too distracted to dodge a second time. Yuichiro was proud of their teamwork.

Which was why he had a feeling this next mission would be their toughest yet. Because it involved doing one of Yuichiro’s absolute least favorite things in the entire world.

Working with other people.

Yuichiro met his two colleagues at the designated meeting spot, just on the edge of the town they were assigned to protect. They were a boy and a girl, both older than him. They didn’t wear anything over their uniforms, but the girl’s hair was tied with a flowery bow and the boy’s black hair was windswept. The girl smiled as he approached, while the boy looked wary.

“Hello, you must be Tokito, right?” she asked.

“Yeah… Sorry, what are your names? I don’t think Ginko told me.” The crow probably had told him, but Yuichiro had no problem blaming her for him not knowing their names. Not because he forgot, but because he didn’t care in the first place.

“I’m Kasumi Yuuki, and this is my little brother, Haru. You can call us by our first names so there’s no confusion.”

“Oh, right,” Yuichiro frowned. It would be helpful to know what names to call in the heat of battle. He would prefer these strangers not address him by his given name, but it couldn’t be helped. “Then, I guess you can do the same with us. I’m Yuichiro, and my brother is Muichiro.”

“Brother? You mean… the demon?” Haru asked, looking suspiciously at the basket Yuichiro carried.

Yuichiro narrowed his eyes. “No, I meant my brother. He’s a demon slayer too.”

“How can a demon slay demons? Does he even have a-”

“Haru, that’s enough,” Kasumi cut him off. “We’re all on the same side here, aren’t we? Come on, we have a mission to complete. If we finish quickly, we can get udon to celebrate!”

“She’s right,” Yuichiro agreed, welcoming the distraction. “What do we know so far about the situation?”

“There have been reports of disappearances around this town, increasing in number over the past couple weeks. The Corps suspects it might be multiple demons working together.” Kasumi explained.

“Then they’re probably pretty weak, huh?”

“Maybe, but we can’t be sure of that,” Haru said with a bit more bite than necessary. “Don’t let your guard down.”

“Same to you,” Yuichiro bit back. He already didn’t like this guy.

“Oh boy…” Kasumi muttered, trying to keep up a cheery face. “Let’s just… get moving, shall we?”

The two boys huffed and agreed, and the quartet made their way towards the forest just beyond the town. It was really more of a swamp than a forest, damp and with a heavy, musky smell. Yuichiro pinched his nose and tried to ignore the wetness beneath his feet. Even with a chill in the air, his uniform felt too tight; he really needed to make some modifications to it once he had the time to do so.

“Hold on,” he called to his two companions. The sibling pair turned to him as he took off Muichiro’s basket and set it on the ground.

“You’re bringing him out?” Haru grumbled. Yuichiro shot him a venomous glare.

“If you wanna find those demons, Muichiro is your best bet.” He turned away from Haru and knelt beside the basket. “You can come out now, Mui. It’s okay.”

The basket shook, and then the lid popped off as a cloud of mist billowed out. Haru stood protectively in front of his sister as the mist solidified into the form of a young boy. Muichiro wore a small, serene smile as he looked up at the two.

“Hi!”

Muichiro didn’t wear the Corps’ uniform, but he did have a new uniform of his own. The young demon was clad in a white kimono with teal mist patterns and matching hakama pants, as well as white tabi socks, white zori with teal bands, and a teal obi wrapped around his waist. These clothes were formed from his own cells, and thus able to regenerate and transform with him whenever he turned to mist. Yuichiro appreciated the practicality, but tried not to think too hard about the implications.

“Hi there!” Kasumi greeted him back, making eye contact and smiling cheerfully. “So you’re Muichiro? You’re cuter than I thought you’d be!”

Yuichiro scowled. Did she think he’d be some terrifying monster? It was no secret that they looked exactly the same.

Muichiro, meanwhile, just seemed excited to have someone to talk to. His smile widened as he stared unblinkingly into Kasumi’s eyes. “Thanks! Can call me Mui! Nice to meet you!”

“Aww, you’re the sweetest thing! I’m Kasumi, and… um…” she trailed off, seeming to lose focus. Her eyes looked a little fogged over. Haru looked concerned, and soon directed a withering glare at Muichiro. Yuichiro grimaced and grabbed his twin’s hand.

“Alright, enough chatter. We have a job to do.” He pulled Muichiro away, breaking their eye contact. He walked a distance away, then leaned in and whispered, “You know you’re not supposed to do that.”

“Sorry,” Muichiro muttered. “Forgot…”

Yuichiro looked towards the siblings. Kasumi was shaking her head with a confused look while Haru fussed over her. They spoke between themselves, not nearly so quiet.

“Are you okay, sis? Did that demon do something to you?”

“I’m fine, Haru, so stop worrying. I just got lost in thought, that’s all.”

“Lost in thought? We’re in the middle of demon territory, you can’t-”

Yuichiro turned away and sighed. He hated working with people. “Muichiro, can you find any signs of the demons we’re hunting?”

Muichiro looked around and sniffed the air. His face scrunched up in disgust. “Stinky.” But he continued to walk around and observe the area with a focused expression. After a minute, he pointed east with a clawed hand. “That way.”

Yuichiro smiled. He knew his brother would find something. “You heard him, let’s go.”

Haru grunted and pulled out his sword, a blue blade that marked him as a wielder of Water Breathing. “You two lead. I’ll take up the rear, just in case.”

At the sight of Haru’s blade, Muichiro noticeably tensed up. His face was blank as usual, but it looked more strained. Yuichiro frowned and tried to redirect his attention. “Come on, Mui, we’re all counting on you here.”

It seemed to work, and Muichiro relaxed a little. He nodded and marched on ahead into the marsh. They walked silently in a line, their surroundings dark except for slivers of moonlight and the young demon’s glowing eyes. Yuichiro quickly noticed that Haru’s attention was elsewhere; specifically, it kept diverting forward, towards Muichiro. Yuichiro debated saying something when a pair of voices reached their ears.

“Shut up! It’s my kill, and I’ll deliver it to the Chief!”

“Bullshit, I did all the work to get it in the first place! I’m gonna give it to him!”

Yuichiro held up a hand, signaling for Kasumi and Haru to stop. He and Muichiro crept forward, and that’s when they spotted them; two demons engaged in a fierce argument. Neither noticed the twins. Silently, Yuichiro gestured to his brother and then to the demons. Muichiro nodded.

Mist engulfed the two as Yuichiro shot forward. They were completely caught off guard, and with two swings of his sword, both demons collapsed, headless, to the ground. Yuichiro flicked the blood off his sword and sheathed it as quickly as he could. Thankfully, Muichiro was too occupied to notice as his mist enveloped the crumbling corpses.

It was then he saw the thing the demons had been fighting over: a human corpse, and likely one of the missing townspeople. The man’s throat was slit, but it wasn’t bleeding, suggesting he’d been dead for a while. He hadn’t noticed the smell of it over the stench of the swamp. Digusting monsters. His grip on his sword's hilt tightened.

Yuichiro heard their two companions run up behind him. “Oh no…” Kasumi gasped, her hands covering her mouth.

“Nothing we can do now,” Yuichiro muttered. “We’ll just have to avenge him by killing the rest of these bastards.”

“Why did you kill them both then? We could have questioned one about where the others are,” Haru pointed out angrily. Yuichiro turned to meet his glare with one of his own.

“There’s no need. Now that Muichiro knows what he’s looking for, we’ll find the rest easy.”

“Idiot, we still could have learned more than that!” Haru snapped. “How many of them there are, or if they have any Blood Demon Arts! You think your demon brother’s gonna know that?”

Yuichiro was about to retort, when Kasumi called out, “Wait, do you hear that?”

They stopped to listen, and heard it too: more voices. Muichiro reformed his body and pointed deeper into the marsh. “This way!”

Their group advanced silently, until they found the source of the voices. The thick trees opened up into a large clearing at the edge of a murky lake. Several emaciated demons huddled around a large stone statue depicting… something. Yuichiro couldn’t tell. It kind of looked like a horse? But it had the upper body of a man? Weird.

“That’s a centaur,” Kasumi commented from behind him. “It’s a creature from Greek mythology. I read about it in a book!”

“Whatever it is, it’s ugly.” Yuichiro grumbled, looking in disgust at the crude statue, especially when he noticed the reddish liquid painted over it, and the mutilated piles of meat and bone the demons left at its base.

“It’s like they’re worshipping it,” Haru observed, looking just as disgusted as Yuichiro felt.

“Might be Chief,” Muichiro said, glaring at the demons.

Chief? Suddenly Yuichiro remembered. “That’s right, those demons said something about a chief. So they have a leader, then. But it doesn’t seem to be here now, so let’s take care of them while we can.”

His companions all nodded their agreement. Yuichiro gestured to Muichiro again, and mist swallowed up the soon-to-be battlefield as the fight began.

—

Mui was aware of everything that happened within his Haze. He felt everything it touched, and as his mist swept the battlefield, he knew instantly what they were up against. Seven demons versus three demon slayers.

Anger propelled his claws forward as he followed Yui. He slashed one demon across the face and followed with a kick that knocked it to the ground. He vanished back into the mist as Yui dove in with the fourth form and sliced its head off. Several feet away, he felt Kasumi and Haru using their Water Breathing together to dispatch another demon. Five more to go.

Yui was right; these demons were weak, though he wasn’t sure it was the demons’ faults. They seemed starved; was all their food going to their chief? Where was the chief anyway? He heard Haru cry out as a demon knocked him back, and shoved those thoughts aside as he dove in to help. He reformed behind the demon and tackled it to the ground, then jumped off as Haru’s sword came down to cut through its neck. Mui smiled at the boy, but Haru only scowled and ran off into the fog. His smile fell, but he shook his head and retreated back into the mist.

Despite the slayer’s animosity, Mui followed Haru to assure his safety. He watched as he and Yui stumbled across each other, swords raised until they realized who the other was. Growls beyond the mist drove them to stand back to back, watching and listening for approaching enemies.

“Keeping up?” Yui asked with thinly veiled contempt.

“I’d be doing better without all this damned mist! How can you even stand being in this stuff? It’s making my skin itch like crazy!” Haru complained.

“Huh?” Yui looked confused. “The hell are you talking about? It doesn’t- Look out!”

Yui shoved Haru out of the way as a demon took a swipe at him. He drove his sword through the demon’s chest and pushed them both back into the mist and out of Haru’s sight.

Huh? Mui didn’t understand, but he pulled his mist away from his human companions. Unfortunately, this meant it was easier for the demons to spot them. He saw one leap at Kasumi while she was finishing beheading another, and he jumped in to help her. With a shout, his claws ripped across the demon’s back. It stumbled, and Kasumi spun around and cut its head off while it was distracted.

“Whew, thanks for the save!” she said, smiling gratefully.

Mui returned the smile, but then he sensed something new moving through the mist. Something big. And then he spotted it, a dark shape within the fog, looming behind Kasumi. Fear colored his face before anger took over. He snarled and lunged forward, intending to push Kasumi out of the way of the demon’s strike.

“Sis!” Haru’s voice called out as he broke through the mist, sword already in swing… towards Mui. The young demon’s eyes went wide, time seeming to slow as he watched the blade move towards his neck. Why? Weren’t they on the same side?

The new demon’s claw swung at a shocked Kasumi, back turned and none the wiser. He could still save her, but if he did… Mui squeezed his eyes shut and turned to mist just before Haru’s blade could cut through his neck.

I’m sorry!

“Haru-!” Kasumi cut off with a gasp as sharp claws raked across her back, the Corps’ uniform offering no protection from the demon’s attack. She collapsed to the ground, deep gashes bleeding the ground red beneath her. Haru’s face went white with horror as he stood over her.

“S-Sis!” The shock left him frozen as the large demon swung at him next. His sword was raised to block, but the demon easily knocked it from his trembling grasp. Haru’s legs gave out beneath him and he collapsed next to Kasumi.

Mui watched from the mist. The past few seconds had moved slowly for him, like he wasn’t even there, like he was an outsider watching someone else. But Kasumi’s pain, Haru’s fear, and the blood soaking the ground… They triggered something in him. Memories of a small house, a wicked grin, and his brother screaming.

He saw red.

—

Yuichiro was swinging his sword towards yet another demon when the mist around him suddenly vanished. The demon spotted him and lashed out, though that didn’t save it as his blade cut through its neck. But it was anything but a clean cut, and he felt a sting on his cheek where the monster’s claws grazed him.

“Muichiro?” He called on instinct, looking around, and that’s when he heard his brother howl, a feral sound full of fury. He turned and saw Kasumi and Haru, the former prone and bleeding on the ground while the latter hunched over her. Yuichiro bit back a curse; this was not good!

Muichiro’s mist coalesced into a solid form as he threw himself at a monstrous demon unlike any of the others here. It had the lower body of a horse and the upper body of a man, both adorned with rusted samurai armor. Its human face had no mouth; instead, a toothy maw adorned its torso where the two halves connected. It was also easily twice Muichiro’s height. His claws slashed at its face, but the demon recovered quickly and retaliated with a punch that sent Muichiro flying into a tree with a loud crack.

“Mui! Mist Breathing, Fourth Form: Shifting Flow Slash!” Yuichiro dropped low and charged, sword slicing through the demon’s left leg. It grunted in surprise, but otherwise gave no reaction to the loss of the limb.

“Hmph. So the Demon Slayer Corps sends children to fight me. Pitiful!” the demon spoke with the mouth on its torso. It reared back, and its other foreleg came down to stomp on Yuichiro, forcing him to jump back.

“This thing’s huge!” Was this the demons’ chief depicted in the centaur statue? How had something this big snuck up on them? He chanced a glance at Kasumi, and couldn’t help the curse that slipped out at the sight of all the blood surrounding her. “Shit!”

Muichiro roared and split up into mist again. The cloud flew towards the demon and surrounded it, clinging like a second skin. The demon stumbled back, blinded, and it gave Yuichiro some time to assess the situation.

The biggest problem was that Kasumi was losing blood fast. Yuichiro pulled a supply of bandages from his uniform pocket and tried to wrap up the wounds, but they were being soaked through as fast as he could wrap them. He cursed and turned to the frozen Haru.

“Don’t just sit there! Help me!”

Haru snapped out of his daze and nodded frantically. They worked to stop the bleeding and hold pressure on the wounds, but Yuichiro could already tell this was a fool’s mission.

“Kasumi, can you hear me?”

“…Y-Yeah…” Her voice was weak.

“You need to use Recovery Breathing, or you are going to bleed to death! Focus on your breathing, and close off the flow of blood to the wounds! Do it now!”

What they really needed was the Kakushi to get her somewhere safe. But even though there were some right in the town, they couldn’t come here with this demon still alive. Yuichiro looked up; the Chief was still trapped in Muichiro’s mist, its skin sizzling and melting to expose bone and muscle underneath. He needed to help behead it, but he wasn’t sure Haru could stem the bleeding on his own.

Then he spotted Haru’s sword, lying on the damp earthen floor. “Muichiro!” He pointed to the blade. “Use the sword! You need to kill it now!”

Muichiro’s misty form moved strangely; it swelled and writhed, and the demon roared as the sizzling of its skin increased in intensity.

“Come on, Mui! We need to get Kasumi help!”

Suddenly Muichiro wretched himself away from the demon. His mist fell to the ground and reformed into his body. He glared at the demon, not once looking at the sword. “Don’t need it!”

“Don’t be stubborn! You can’t-”

“Don’t need it!” Muichiro repeated with a shout. He lunged forward, and faster than the eye could blink, slashed through the joints in all four of the demon’s legs. It fell to its knees, and Muichiro leapt over its head, claws raking across the back of its neck. But the demon reached back and caught him, throwing him into the ground with superhuman force. Muichiro’s body exploded into mist before impact, then reformed as he jumped right back into the fray.

Damn it, Muichiro wasn’t listening to him at all. Yuichiro grit his teeth and looked between Kasumi and the demon. He felt frozen with indecision. Could he leave Kasumi long enough to kill the demon himself? He didn’t think so. “Fine, then switch places with me! Hold pressure while I take care of the demon!”

Muichiro jumped back, shot him a very uncharacteristic glare, and then leapt back again as the demon’s hooves trampled the spot he’d just stood. Then the Chief's eyes turned towards the three humans.

Shit.

Yuichiro reached for his sword, but his blood-slicked hand fumbled with the hilt. The Chief struck out with its fist extended, only for it to suddenly be severed at the wrist. Muichiro landed in front of his brother and growled a warning at the demon.

Yuichiro looked at his brother with sympathy; he understood his anger, but this couldn’t continue. He placed a hand on Muichiro's back. His brother flinched, but the touch seemed to ground him; he turned his head to face him. Yuichiro took a deep breath and spoke calmly. “Look, Muichiro, I get it. You want to prove yourself. And I know you could handle this demon if it was just us here. But Kasumi is going to die before the sun comes up. She needs help now. So let me fight the demon this time, okay?”

For a moment, Muichiro didn’t respond, his body wound tight. But then he shuddered, the tension leaving him as he slumped and nodded. “…Okay.”

Yuichiro smiled in relief. He and Muichiro switched spots, his brother helping a shaking Haru while he stood with his sword drawn to confront the centaur demon.

“You believe that you can kill me? Arrogant child!” The Chief stamped its hooves. “I was a samurai of the Meiji-”

“Shut up. I don’t have time to listen to your crap.” Yuichiro interrupted him. He looked up at the demon’s eyes. No number; it wasn’t a Demon Moon. But that didn’t mean he could let his guard down. One hit from something this size would likely reduce him to paste.

So, don’t get hit then.

“Insolence!” The demon slammed its fist down, and Yuichiro dodged to the side. He jumped back, hoping to lure the demon away from his teammates. It took the bait and stomped towards him before breaking into a full charge.

“Mist Breathing, Sixth Form: Lunar-Dispersing Mist!”

Yuichiro leapt into the air, over the demon’s head as it charged under him, his sword slashing to cut through its arms. The Chief stopped and he landed on its back, but before he could swing for its neck, it took off running again. Yuichiro yelped and dug his sword into its back to avoid being thrown off as it bucked about.

“Tokito!”

“Yui!”

“I have… it under… control!” Yuichiro tried to brush off Haru and Muichiro’s shouts as the demon tried its hardest to throw him off.

“How dare you-!”

“Just shut up and die already!” As the Chief bucked, Yuichiro pulled out his sword and jumped, the extra force throwing him high into the air. The centaur demon watched as he reached the height of his jump and started to fall. Its torso-mouth turned up in a toothy grin, claws drawn back to strike once he came into range.

“Water Breathing, First Form: Water Surface Slash!”

It buckled, its balance lost. The Chief cried out and turned its gaze to Haru, sword in his hands and a deep gash through its right hind leg. He backed up, and Muichiro leapt in, claws slicing through the rest of the limb. The demon collapsed onto its remaining hind leg.

“No!” It tried to swing at Yuichiro a second too late.

“Mist Breathing, Second Form: Eight Layered Mist!”

The demon’s arm was sliced to pieces, and with a glint of white under the moonlight, its head separated from its neck. Yuichiro landed on the wet dirt, and the demon’s head followed a moment later.

“Yui!” As soon as he stood up, Muichiro leapt at him and wrapped him in a hug.

“Muichiro? Haru?” Yuichiro was confused as he watched the older boy approach. Not that he didn’t appreciate the help, but… “What about-”

“Bleeding stopped,” Muichiro told him as he let go and backed up. His small smile looked strained. “Will be okay… for now.”

Yuichiro nodded. He heard their crows caw and fly overhead.

“The demon has been defeated! The Kakushi are on the way!”

Haru breathed a sigh of relief. “Then, she’ll be okay… Thank goodness.”

“Thank goodness…” Muichiro nodded. His smile slipped and he moved to cling to Yuichiro’s arm.

“Mui? Is something wrong?” he asked, somewhat redundantly. It was obvious that something was bothering him.

Muichiro didn’t answer, which was confirmation enough. Yuichiro grabbed his arm and started to lead him away. He glanced at Haru. “We won’t go far. You should stay with Kasumi until the Kakushi get here.”

The other slayer didn’t argue, his face clearly troubled. “…Right.”

Once Yuichiro was sure they were out of hearing range, he stopped and turned to his twin. “Muichiro, what happened back there? You’re not usually that…”

Stubborn? Reckless? Uncooperative? There were a lot of words he could use to describe that situation, none of them good.

Muichiro’s face was impassive, but his lips twitched as he fought back a frown. “Did I… cause trouble for you? Yui?”

“Huh? Well, I uh…” Yuichiro stuttered, unsure of how to answer. “I mean, you do worry me, sometimes…”

“Oh…” Muichiro looked downcast. “Sorry.”

“You don’t need to apologize for it. It’s just, sometimes it’s hard to tell what you’re thinking, and if you don’t say anything, I can’t really help, you know?”

“…Yeah, I know. Sor…” Muichiro shook his head and looked away, hair hiding his face. A long silence followed.

Yuichiro sighed. He knew full well what was bothering his brother. He’d known for the past two weeks. “Muichiro, I’m sorry the nichirin sword didn’t change color for you.”

Muichiro jumped, his head whipping around to face him. “Huh? Why sorry? Not your fault!”

“Well, it’s not your fault, either. You’re beyond skilled at Mist Breathing, and I’m sure you have an affinity for it. But the sword just doesn’t change color for demons. It sucks, I get it, but it doesn’t do you any good to keep being upset. Can’t you-”

“No.”

“I didn’t even-!” Yuichiro groaned and put a hand to his face. Deep breaths, he told himself. “…Okay, you don’t have to use a sword. But, can I ask you to remember something?”

Muichiro tilted his head, confused.

“Don’t think you have to prove yourself to me. So you can’t kill demons on your own. That’s fine, because I’m here for you. We’re a team; we fight better when we’re together.

Any anger his brother still held faded away after that, and he just looked sad. After a minute, Muichiro asked, “Team… but… what can I do… that you can’t?”

Yuichiro grimaced. His twin’s lack of self-confidence was nothing new, as far back as when he’d been human, but trying to do something about it was… difficult.

“Muichiro, if you think you’re useless, that couldn’t be further from the truth. I wouldn’t be even half as good at fighting demons if it wasn’t for your mist making my techniques stronger.”

“…So I just… support you?” Muichiro seemed less than happy at the idea. Yuichiro felt his composure start to slip, panic building in the back of his mind. He was not prepared for this kind of discussion, and he didn’t know what to say that wouldn’t make Muichiro feel worse.

“N-No, of course not! You do so much more than that! You’ve saved my life! You watch my back and I watch yours; that’s what it means to be a team! And besides! If it wasn’t for you, I wouldn’t have the strength to do any of this! You’re the only reason I’m standing here right now.”

A little light entered Muichiro’s eyes. “Really?” There was a note of desperation in his voice. “Really mean that?”

“Of course I mean it,” Yuichiro scoffed and crossed his arms. “Would I say it if it wasn't true?”

Muichiro blinked. He seemed to be thinking hard. “No…?”

Why did he sound so uncertain? Yuichiro sighed inwardly but kept talking. “Then trust me. And I don’t want to hear you talking about yourself like that again either, okay?”

“…Okay.” Muichiro gave him a fragile smile. Suddenly the two heard a caw overhead. Yuichiro looked up, and Ginko flew down to rest on his shoulder before shouting right in his ear.

“New mission, new mission! Head south! Demons have been reported near a fishing village!” Yuichiro scowled and tried to cover his ringing ear. Why did she have to be so loud? The only reason he hadn't asked for a different crow by now was because Muichiro had unfortunately grown attached to the annoying thing.

“Already, seriously?” They’d only just finished this one! Not to mention he wasn’t done talking to Muichiro! But his brother turned away with a frown and started walking back towards the siblings and the Kakushi who were now tending to them, so it seemed their conversation was over.

Yuichiro scowled and followed. What an awful night this had turned out to be.

—

They needed to rest before traveling to their next mission, so the twins rented a room in one of the town’s inns. Mui waited in the bed as Yui cleaned up in the washroom. He’d never slept in a bed before; he couldn’t help but marvel at how soft and bouncy the mattress was compared to a futon. That is, until his claws caught on the sheets, ripping through the delicate fabrics and spilling out cotton. Oops.

Yui took that moment to step out of the washroom, garbed in his nightclothes, and Mui hastily sat on the rip to cover it up. He smiled as Yui gave him a strange look.

“I’d ask what you did, but honestly, I don’t want to know right now. It’s late and I’m tired.”

Yui climbed into bed and Mui laid down beside him. “Some night, huh?”

“Mm-hm,” Mui nodded. His smile slipped. He wasn’t proud of how he’d acted tonight. He'd just been so angry. At the demon, and at himself.

“That Haru guy was a real jerk, too.”

“Hm?” Haru? …Oh, right, the older boy from the mission. He’d forgotten. Actually, he couldn’t remember either of the siblings’ names; a heavy stone-like feeling weighed on his chest.

“I mean, who does he think he is, treating you like that?” He turned on his side and gave Mui a fierce look. “Mui, if he insulted you, I want you to tell me now. I’ll beat him to a pulp!”

“Umm…” Mui smiled awkwardly. He had a feeling Yui would do much worse if he found out what Haru had almost done during the battle. But even if he was hurt by Haru’s lack of trust - not to mention the attempt to kill him - he didn’t want Yui trying to get revenge for him. “Not… needed.”

“Hmph,” Yui rolled onto his back again. “Fine, but I still don’t like him!”

Mui couldn't help but chuckle at how overly indignant he sounded. Like he was putting on a show to distract them both from what had happened. Mui hoped that girl would be okay. He wanted to apologize for not being able to protect her. Maybe they could visit her at the Butterfly Estate after this next mission? “Should get some sleep, Yui.”

Yui sighed. “Yeah, I know. And I want you to sleep too, okay Mui? I’ll be counting on you once we get to that village.”

“Yeah, me too. Good night, Yui.”

“Good night, Muichiro.” Yui rolled over and closed his eyes. Mui stared at his back, silently listening until he heard his breathing even out. But even if Yui was asleep, Mui found it to be a much more difficult task. Part of it was that he didn’t really need the sleep, but a larger part was that he couldn’t stop thinking.

Yui was… really kind. He was trying his hardest to assure Mui that he was useful and that they were a team. It made him happy, but it didn't get rid of the aching in his heart. He and Yui were a demon and a human; no matter what, they weren’t the same. Mui had held onto the hope that they could still be demon slayers together, but that hope had been crushed two weeks ago, when Yui’s swordsmith had brought that second sword as a gift. A sword that had failed to change color in his hands, and left him with a nauseating, sludge-like feeling in the pit of his stomach ever since.

Mui had hoped that if he ignored the sludgy feeling long enough, then he’d forget about it like he did everything else. But he didn’t. Of all things, why was it this awful feeling that he remembered most? It was so unfair.

Yui had told him that the sword didn’t need to change color to slay demons, but some part of him screamed that it was important that the sword be his own and no one else’s. Because how could he be a demon slayer without his own sword? And if he couldn’t be a demon slayer, how could he and Yui ever be equals?

He wanted to talk to Yui, but Yui was still sleeping. His worries weren’t worth waking him up for; humans needed their sleep. The mist crept in at the edges of his vision, but he didn’t try to stop it. Mui closed his eyes and let the fog claim him as the night silently passed.

Chapter Text

Three days after their latest mission, Yuichiro and Muichiro were on their way back to the Ubuyashiki Estate. At Muichiro’s insistence, however, they first stopped by the Butterfly Estate. The younger twin wanted to check on the siblings, Kasumi and Haru, and Yuichiro couldn’t deny that he was curious about the girl’s condition. Her wounds had been quite severe; he hoped for the best but expected the worst.

Yuichiro was greeted by the three Butterfly girls as he entered the Estate’s doors. He was familiar with them from previous visits, enough to at least know them by name. Sumi was the first to address him. “Yuichiro! Oh, and Muichiro too! Welcome back!”

“How was your mission?” Kiyo asked.

Yuichiro’s expression darkened. “It was fine. Neither of us got hurt.” He spoke quickly and didn’t elaborate.

“Oh, then are you here for an appointment with Shinobu?” Naho tilted her head.

“No. Actually, Muichiro wanted to check on someone. Kasumi Yuuki. Is she here?”

“Oh, yes! You’re in luck, actually! She just woke up yesterday!” Sumi told him enthusiastically. However, Yuichiro couldn’t help but think her smile looked a little forced.

“Would you like to see her? She did ask about you, you know?” Kiyo asked while Naho nodded. Both of them seemed likewise uncomfortable.

Yuichiro nodded, and the three girls led him and his twin down the halls until they stopped in front of a closed door. “Let us know if you need anything!” Naho said before they ran off, leaving just Yuichiro and his brother.

He knocked, and heard a feminine voice call out “Come in!” before opening the door.

“Oh, Yuichiro! Hi!” Kasumi greeted him cheerfully. She was sat up in a bed, Haru sitting in a chair beside her. The boy glanced his way and his eyes narrowed, clearly upset at having his time with his sister interrupted. “Haru and I were talking earlier about if you’d come by or not. He was so convinced you wouldn’t that he bet a month of doing all the cleaning around the house. But it looks like you lose, little bro!”

“Really? Then I guess it was worth coming here just for that,” Yuichiro smirked at the boy’s misfortune. “But really, it was Muichiro who wanted to see you.”

“Oh? How sweet!” Kasumi gushed. “Haru, go close the curtains, would you?”

Haru reluctantly obeyed, and Yuichiro helped him out before setting the basket down in the now much darker room. “Come on out, Muichiro.”

His twin wasted no time in doing just that, mist reforming at the bottom of Kasumi’s bed. The bed shook from the added weight. "Hi!"

“Hey, get off the bed, stupid! She’s still recovering!” Haru snapped. Yuichiro barely resisted the urge to punch him in the face.

“Don’t you call-!”

“Alright, you guys, that’s enough. No fighting. And I don’t mind, Haru,” Kasumi intervened. Muichiro crawled over to sit beside her, and she tried to make room for him with some difficulty. A pained wince escaped her before she smiled again and started patting his head.

“…So, how are you doing?” Yuichiro asked, finally getting to the root of their visit.

Kasumi’s expression instantly grew strained. She seemed to force herself to smile as she spoke. “I’m… well. As well as I can be, anyway. Lady Kocho says the demon’s claws cut through the nerves in my spinal cord, so I can’t feel or move anything below my waist. It’s unlikely that I’ll ever walk again.”

The mood in the room turned crushingly somber. No one dared to speak a word. Yuichiro was shocked; how could she say something like that so casually? He couldn’t even imagine what that would feel like, to suddenly be deprived of the use of such an integral part of one’s body.

Kasumi went on in absence of a response. “Hey, don’t look so down! At least I’m alive, right? I have you all to thank for that.”

It didn’t help the mood. Muichiro’s body shook; his face was blank but there were tears in his eyes. “…Sorry… Sorry… My fault…”

Yuichiro winced. Muichiro must be blaming himself for not having sensed the demon in time.

“Oh, Muichiro, please don’t blame yourself,” Kasumi tried to assure him, brushing a hand through his long hair. “This kind of work is dangerous; we all knew that. And I know you tried your best.”

Muichiro’s lips turned in a small frown, the glow in his eyes darkening. He seemed… frustrated? Yuichiro wasn’t sure. Out of the corner of his eye, he noticed Haru turning away, hiding his face from them.

Kasumi was right; being a demon slayer was dangerous. Extremely so. Yuichiro counted himself lucky that he hadn’t sustained any serious injuries against the demons he’d fought so far, but how long could that last? The very real possibility of going from perfectly healthy to permanently bedridden, or worse, in mere seconds… The very thought made him feel dizzy.

“Yui…” Muichiro was at his side in an instant, peering at him with still-teary eyes. Yuichiro shook his head.

“I’m fine, don’t worry about me. Um… I’m sorry for your loss, Kasumi.”

Kasumi shook her head. “Don’t be sorry. It barely hurts, and honestly? I kind of think of this as a blessing.”

“A blessing?” Yuichiro raised an eyebrow. How could losing the use of one’s legs be a blessing?

“Well, now Haru and I can retire. We became demon slayers because we lost our parents to demons. But, I’ve been thinking for a while now that they wouldn’t have wanted us risking our lives to avenge them. So, I’ll think of this as a blessing, as the gods telling us it’s okay to go home and live a normal life.”

A normal life. Yuichiro scowled; he wanted that for himself and Muichiro. But that was impossible now. Even if he were to be so injured he could no longer fight, he still couldn’t live a normal existence, not while Muichiro was still a demon. But he wasn’t going to feel jealous of a crippled girl who would need care for the rest of her life. He was going to save Muichiro or die trying.

“…I’m going out for a bit. I need some fresh air.” Haru declared suddenly, turning and almost running out of the room. Muichiro blinked slowly, and then his eyes went wide.

“Going out too!” He rushed out of the room in a blur of white.

“Huh? Mui, wait! The sun-!” Yuichiro moved to go after him, but Kasumi’s voice stopped him.

“I’m sure he’ll be fine, Yuichiro. I think he wants to talk to Haru alone, anyway.”

He froze in his tracks, bewildered. “What? Why?”

“That’s not my place to say. You should ask him later.” Kasumi dodged the question. She paused, and then looked him in the eye as she spoke. “You really care about Muichiro, huh?”

Yuichiro frowned and crossed his arms. “Duh, of course I do.” What kind of stupid question was that?

“That’s good. But you know, older siblings and younger siblings, we’re not really so different. We both want to protect the other. That’s why Haru is always so… abrasive with other people when I’m around. He’s really scared of losing the last of his family. I get the feeling that you’re pretty similar, in that regard.”

Yuichiro scoffed. Maybe that was true, but honestly, knowing how similar they were only made him dislike the older boy more. “Where are you going with this?”

“Just… be careful. It’s possible to be too protective, you know?”

Too protective? Yuichiro wasn’t sure what she was getting at. Yeah, he could be harsh with Muichiro, and he usually regretted it after, but sometimes it was necessary. Muichiro was still too kind and naive for the world they lived in. And in many ways, he was even more vulnerable as a demon than he'd been as a human. As strong as Muichiro was, the simple truth was that Muichiro was his little brother and he needed to keep him safe. That was Yuichiro's purpose in this unkind world.

He struggled to not show his irritation. What did Kasumi know about them, anyway? They weren’t friends; they were barely acquaintances. What gave her the right to sound so wise when she was only a teenager herself?

“Hmph. I’ll… keep that in mind. But I need to go make sure my brother is okay.”

“Right. I won’t keep you any longer, then.”

Yuichiro nodded and headed towards the still open door. At the entrance, he paused. His irritation drained away, replaced by familiar guilt. She was only trying to help, a part of him whispered. He sighed and looked back. “Good luck, Kasumi.”

He walked out and closed the door behind him before he could feel any more awkward, but he did catch her grateful smile as he left. Yuichiro tried to ignore the uncomfortable feeling in his gut; he never was good with goodbyes.

As he walked down the hall, he heard hushed voices from around the corner. He instantly recognized them as Haru and Muichiro and stopped to listen.

“…Forgive… you.” That was Muichiro’s voice, so quiet he almost didn’t hear him.

“…Thanks...” Haru’s voice was just as quiet, choked and sounding like he was on the verge of tears.

Yuichiro raised an eyebrow. What was he apologizing for? He had a feeling that something had happened between them before Kasumi confirmed it, but for Haru to be in tears over it, it must have been serious. And whatever it was, it was something Muichiro hadn’t wanted to share with him, either. That stung, admittedly, but he must have had his reasons.

Haru spoke again, breaking him from his thoughts. “It’s just… it’s all my fault. Sis can’t even… how are we gonna survive?”

His voice was quavering. He heard Muichiro hum, followed by the shuffling of clothes. “Don’t worry. Will be alright. Cause you and Kasumi… have each other.”

Yuichiro couldn’t help smiling; Muichiro really was too kind and naive for his own good. It was endearing and infuriating in equal measure. In this case, it was a little bit of both. The brief smile slipped away. He still didn’t know what Muichiro was even forgiving him for, but he had a nagging suspicion that his brother was brushing aside his own hurt feelings for Haru’s sake. Yuichiro finally decided to intervene, but in a way that didn’t make him look like he’d just been eavesdropping.

“Muichiro! Where are you?” He called out loudly, bringing the conversation around the corner to a grinding halt. He rounded the corner a second later to see Muichiro pulling his arms back and holding them up to his chest. He blinked at Yuichiro before grinning.

“Yui!”

“There you are,” Yuichiro grumbled. “You have to be careful when walking around during the day like this. There’s way too many windows around.”

“I know,” Muichiro said nonchalantly. “Don’t worry.”

You make me worry; Yuichiro almost said that out loud, but Kasumi's parting words popped into his head, and he held his tongue. He would probably just make Muichiro sad, anyway. So instead he asked, “What were you two doing?”

“Nothing,” Haru crossed his arms and turned away with a glare. All his previous vulnerability had disappeared near instantly.

Yuichiro groaned. “Fine, be that way. Mui, are you ready to go? I wanna sleep for a week after all this.”

Muichiro giggled and nodded. “Yeah. Let’s go. Bye, Haru.”

Haru grunted and kept his back turned to them. But as they walked away, Yuichiro heard a barely audible “Bye,” from the boy. When he looked back, however, Haru was gone, heading back to his sister. He wondered if he had just imagined it.

—

After leaving the Butterfly Estate behind, Yuichiro and Muichiro returned to the Ubuyashiki Estate. Yuichiro hoped they wouldn’t have another mission for at least a few days. The last mission had been unpleasant, to say the least. The demons near the fishing village had been two children; young, weak things. Yuichiro had almost stayed his blade until a third demon, their older brother of all things, attacked from behind. If it wasn’t for Muichiro, that night could have ended very differently.

It was hard, but Yuichiro had to remind himself that, no matter their age or appearance, a demon was a demon. Given half the chance, they’d tear his throat out and feast on the remains. Muichiro was the exception, not the rule.

“Yuichiroooo!”

Yuichiro was broken out of his gloomy thoughts by a loud, high-pitched voice. He recognized it immediately, letting out a sigh as he saw those familiar pink and green curls bouncing along, their owner sprinting towards him.

“Miss Kanroji… it’s- ugh!” He didn’t get to finish as he was suddenly swept up in a bone crushing hug, the culprit crying with joy.

“Yuichiro, it’s so good to see you again!”

“Y-You too…! Now let… go…!” He grumbled and tried to wriggle out of her grip. Why did this have to happen every time they saw each other?!

“Oh, sorry!” She squealed and let go, finally allowing Yuichiro to catch his breath. “Is Muichiro with you as well?”

“Yeah, he’s here.” It was daytime though, so of course he couldn’t come out. “Miss Kanroji-”

“Yuichiro, I told you that you can just call me Mitsuri! There’s no need for formalities; I think of you as one of my little brothers already! Muichiro too!”

Yuichiro almost wanted to say he didn’t think of her as a big sister, but even he wasn’t that cruel. “Okay… Mitsuri… What are you doing here?”

Mitsuri’s smile somehow grew even bigger. Her cheeks puffed out, like she was restraining herself from blurting out some big, juicy secret. “…Okay, I’ll tell you! It’s not like it’s really a secret anyway!” She did a twirl and announced, “You’re looking at the new Love Hashira, Mitsuri Kanroji!”

Hashira? Yuichiro hadn’t even realized there was an opening in the ranks. But from what he had seen of Kyojuro’s tsugoku in battle, she was exceptionally strong and flexible. Even with how… ditzy she was, he wasn’t too surprised that she could achieve the rank of Hashira.

But, wait…

“Love Hashira? Aren’t you Kyojuro’s tsugoku?”

“Mmm, I was, but… learning Flame Breathing wasn’t really working out,” Mitsuri admitted sheepishly. “So, I developed my own way of fighting, Love Breathing!”

Huh, perhaps Yuichiro should give her more credit, if she was smart enough to develop an entirely new breathing style. “Huh. Congratulations, then.”

“Thank you!”

“Hey, to become a Hashira, you have to defeat a Lower Moon, right?” Yuichiro remembered Tamayo’s words, about collecting the blood of powerful demons to develop a cure for Muichiro. But none of the demons they’d fought so far had even come close to that level.

“Uh huh, that’s one way to do it,” Mitsuri nodded.

“Is that how you did it? Is it scary, facing one of the Twelve Moons?” If he wanted to save Muichiro, he was going to have to face one himself one day.

“Hmm…” Mitsuri looked deep in thought. “Well, fighting demons is always scary to some extent. You never know which fight might end up being your last. But that’s why you’ve gotta face it head on, and give it everything you’ve got, every time! Even if it is one of the Twelve, just fight with all you have, so you don’t have any regrets!”

Yuichiro was taken aback. It was times like these that Kyojuro’s influence really shined through. But Mitsuri’s words… They made his chest feel lighter. Kyojuro and Mitsuri, they were chosen ones who could become stronger to protect people other than themselves.

“Oh, I forgot!” Mitsuri suddenly shouted. “I have to go, I’m meeting Iguro for lunch to celebrate!”

“O-Oh, okay… Is Kyojuro here?”

“Sorry, he and everyone else already left an hour ago. I just stuck around to talk to the Master about my new duties as a Hashira!” Mitsuri explained. “Anyway, I really do have to go! Good luck with your missions, Yuichiro, Muichiro!”

With that, Mitsuri took off down the road towards town, leaving the twins to themselves. Yuichiro resumed his walk towards the Estate, the silence now weighing on him. He wondered if he’d see her again.

Yuichiro shook his head fiercely. Mitsuri was a Hashira now; she’d be fine. He didn’t want to think about such things now. He just wanted to rest. Too bad his mind always had other plans.

“Hey, Mui? Do you think we’re strong enough to defeat a Lower Moon?” They were still only twelve, after all. They were getting stronger every day, but some things couldn’t be compensated for with training.

Muichiro hummed inside the basket. “Don’t worry. Will be okay. We can do anything… together.”

It was the same sentiment he’d given to Haru. Yuichiro smiled despite himself. “Yeah, you’re right.”

He pushed his doubts down and kept walking. He wanted to greet the Master before they retired for the day.

—

“New mission, new mission! Head east to Mount Takao! Head east to Mount Takao!”

Yuichiro felt a headache forming as he was jolted out of sleep. He groaned into his pillow before slowly pulling himself out from his futon. The boy reached for the sword that lay beside him.

“At this time, really…?” They had only gotten back from their last mission yesterday…

“Yes, at this time!” His crow squawked. “There have been reports of demons on Mount Takao! Many slayers have been sent to investigate and have not returned!”

Well that boded well. “Fine, I’m going. Let me get dressed.”

Muichiro chuckled and petted Ginko’s head. She immediately leaned into his touch, and even more so when he started gently scratching her belly. Yuichiro groaned again. Stupid bird.

Within the hour, Yuichiro and his twin were on their way. Mount Takao wasn’t too far, a couple days with minimal rest along the way. He wondered about the situation. How many slayers had already been sent to this site? How many until a Hashira was needed?

A sense of foreboding ran up his spine, but it wouldn’t stop him. He steeled himself and continued running.

—

Two days later, the twins reached Mount Takao. There was a town not far from the base of the mountain, with its own Wisteria Inn that they stayed in until nightfall. The old lady in charge of the inn was very sweet, even giving them candies as if they were little kids. Yuichiro couldn’t begrudge her too much for it; to someone that old, they would seem like small children in comparison.

Muichiro, on the other hand, was so excited that he forgot he couldn’t eat human food. Before Yuichiro could stop him, he popped the candy in his mouth and immediately started gagging from the taste. He forced it down anyway because the old lady was right there and he didn’t want to offend her, but as soon as she was out of earshot, he threw it back up. Muichiro proceeded to spend the next few hours curled up in a miserable ball in the corner of their room.

“I tried to warn you,” Yuichiro had told him while rubbing his back and chewing on his own sweets.

“Want die…” Muichiro muttered dramatically in response. Yuichiro patted him sympathetically on the head.

“You’re such a baby,” he teased.

Muichiro swatted his hand away. “Am not. Yui’s just mean. Eating in front of me…”

“Well I’m not letting these go to waste. Besides, we’ll get you food on the mountain,” he shrugged and popped another one in his mouth. Muichiro huffed and turned away, pouting. Yuichiro couldn’t help but laugh.

Eventually, Muichiro got over his sweet-deprived sadness in time for the sun to start setting. They bid goodbye to the Wisteria House caretakers and departed for Mount Takao. The beginnings of winter nipped at the mountain, the last bright autumn leaves clinging to the tree branches. No snow had fallen yet. It reminded Yuichiro of home.

But there was an ominous aura in the air. Demons definitely lurked here. He adjusted the basket's straps and kept moving. “…Come on, Mui. Stay alert.”

Night was falling quickly. Once that happened, who knew what would come next? They had to keep their guards up. The young slayer made his way up the mountain, silent but for the crunching of fallen leaves beneath his feet. He couldn’t even hear any animals, no bird song or insects buzzing at all.

Actually, there was something. Not a sound, but a smell. A sweet smell that carried on the wind. But there was something else under the scent, something more repulsive. The scent of decay. Yuichiro placed his hand on his sword, ready to draw it at the slightest sign of danger.

The sweet smell was growing stronger as he walked, eventually overpowering the rot with its sheer pungency. And as it grew stronger, he noticed the abnormal amount of sap leaking from the trees around him. The golden, syrupy substance flowed freely, collecting into pools on the ground that he was careful to avoid. Yuichiro was tempted to touch it, but a foreboding feeling deterred him from doing so.

The basket on his back rustled; something seemed to be agitating Muichiro.

“What is it, Muichiro?” Was it the smell? Demon senses were stronger than human ones, after all.

“Is… is someone there?”

Yuichiro jumped and drew his sword, holding it defensively in front of him. But when nothing attacked him immediately, he allowed himself to relax slightly. “Who’s there? Show yourself!”

“I-I can’t. I’m stuck. Are you a demon slayer? Please, help me!” The voice was that of a young man, and Yuichiro looked around in confusion. Then he spotted him, lying on the ground against a far off tree. A human, the majority of his body encased in a cocoon of tree sap.

Yuichiro ran towards the man, whose uniform marked him as a fellow demon slayer. He must have been one of the ones sent to the mountain before him. “What happened? Who did this?”

“Th-There’s a demon on this mountain who controls the trees here. It traps its victims in the sap it makes and leaves them to suffocate. I’m only still alive because the sun was coming up. The others…!”

“Others?” Yuichiro looked up, and his eyes widened in horror. Just beyond the trapped man were several other slayers, all bound against the trees and encased head to toe in sap. Their expressions were ones of frozen agony, helpless to do anything but suffocate inside their airless prisons.

“Please, you have to help me! That demon could come back soon!” Yuichiro tore his eyes away from the horrible scene and nodded. He raised the hilt of his sword, hesitating for a moment as he wondered if breaking the sap might do even more harm. But there wasn’t time to come up with anything else, so he steeled himself and started to pound away at the sap by the slayer’s feet.

Thankfully, the stuff crumbled away easily. He realized that this was not just tree sap, but amber, the fossilized form of the stuff. Only instead of trapping insects, it trapped human beings. The thought made him sick. After a few hits, enough of the amber broke apart for the slayer to move his foot, and he started working his way up the rest of his body.

“Free my sword arm, then I can help!” He complied, and soon the other slayer was freed. “Whew, thanks kid, I owe ya!”

“You don’t look much older than me,” Yuichiro glared, quite sick of all the comments on his age at this point.

“Um, yeah, you’ve got a point. Sorry.” At least he had the decency to look apologetic. “Um, my name is Hayato Fujimoto.”

“Yuichiro Tokito.”

“Tokito? Wait, aren’t you the-“

“Yes, I am. That’s not important right now.” Yuichiro growled and stood up. “We’re going on ahead. You should head back and report to the Master what happened.”

“Wait, hold on! What rank are you?”

“Tsuchinoto.”

Hayato’s eyes went wide. “Eh? You’re a higher rank than me?”

“Is that so surprising?” This guy was really getting on Yuichiro’s nerves.

“S-Sorry! But, even if you’re a Tsuchinoto, you shouldn’t go alone! This demon is a Lower Moon! It’s really dangerous!”

Shock drowned out Yuichiro’s previous irritation. A Lower Moon was here? He’d succeeded easily in his past missions, but against one of the Twelve? They were on a whole different level than other demons. Could he do this?

The basket shifted, reminding him of Muichiro’s presence. Yuichiro’s fears and doubts faded, and he looked forward determinedly. “I’m not alone. We can handle this.”

—

Some minutes of walking later, Yuichiro came to an area where the trees thinned out. He surveyed the area warily, taking note of several small, sparkling objects littering the dirt. They didn’t seem to be from the Lower Moon’s tree sap. What were they?

“Wait! Tokito!” Yuichiro turned around to see the slayer he rescued running up, and his irritation returned tenfold.

“Didn’t I tell you to go back?” he growled.

“You can’t fight a Lower Moon on your own! I’ll back you up!” Hayato insisted, raising his sword.

“I told you, I’m not on my own. I have Muichiro.” Yuichiro reminded him. “And frankly, I don’t know what help you think you’re going to be. I already had to rescue you once, I don’t need to be worrying about you in battle.”

Hayato sighed. “Look, I told you I owed you, and I’m gonna repay that debt.”

“You’re gonna get yourself killed, is what you’re gonna do!” Yuichiro snapped. “Now get out of here, before-”

Muichiro’s basket jumped, catching Yuichiro off guard and throwing off his balance. Mist erupted around him and flooded the area. What-

“Look out!” Hayato burst through the mist and shoved him aside. Yuichiro heard a whistling, and then Hayato’s scream as something long and thin impaled the right side of his chest and nailed him to the tree just behind him.

“Shit!” Yuichiro hissed and turned in the direction the spear had come from. Muichiro’s mist scattered as another spear came his way, and he raised his sword to deflect it. The weapon stabbed into the ground next to him, revealing it to be made of clear crystal.

Muichiro reformed next to him, growling with his fangs bared. Heavy footsteps shook the ground as, without the fog, the demon they’d been sent to hunt was revealed.

The demon was tall and muscular, though a large part of its bulk seemed to be due to the rocky shell covering its body like armor. Crystals jutted out like spikes from its back and arms, and its hands were encased in rocky gauntlets with crystal claws. Its eyes were mismatched, one orange with a diamond-shaped pupil, and the other bearing the kanji for the number four.

Lower Moon Four. Yuichiro grit his teeth and turned to check on Hayato. Muichiro stood protectively between them, giving Yuichiro the chance to run to the other slayer.

“Fujimoto!” He knelt down next to the older boy, grimacing at the amount of blood staining his uniform. He took his sword and cut through the spear on both ends; he knew better than to actually take the weapon out without something to stem the bleeding. “You need to get out of here! Muichiro and I will handle the Lower Moon!”

“That’s…” Hayato’s breathing was harsh, his face contorted in pain. “That’s not the Lower Moon!”

What? “What are you talking about...!” Yuichiro’s eyes turned upward, and his panic increased. Tree sap was oozing from the tree Hayato was pinned to, sliding down towards the slayer. Without thinking about it, Yuichiro swung his sword, cutting through the tree above Hayato’s head before the sap could touch him. But to his surprise, the entire tree quickly turned to ash, falling apart like a demon’s corpse.

The tree was a Blood Demon Art? Were all the trees like that?

A shout from Muichiro drew his attention. Spindly tree roots oozing with sap had twisted around his brother’s feet, distracting him as a spear sprouted from the palm of the Lower Moon Four. Yuichiro shouted a warning as the demon took aim.

“Muichiro!”

His twin burst into mist a second before the spear pierced him. The cloud hovered in place for a moment, then surged forward, past the demon and into the trees behind him. A branch snapped, and something jumped out of the trees and landed beside the Lower Moon.

“Eep! Mogura! You said you’d keep them from finding me!” it shrieked, high pitched and feminine.

Lower Moon Four scoffed and crossed his arms. “Can it, Kohaku. It’s another demon, it can’t kill you.”

“So what?! It wants my blood, just like all the others!”

Yuichiro was stunned. There was another demon? Demons didn’t usually work together unless they were weak, and a Lower Moon certainly wouldn’t work with a weak demon. This one was considerably smaller than the other, dressed in a flowery kimono. She had orange-tinted skin and glittering bronze hair. But most notable were her green jewel-like eyes, one of which also bore a number, the kanji for six.

Yuichiro’s eyes widened at the realization.

This mountain wasn’t just home to a Lower Moon.

It was home to two.

Chapter Text

This mountain was home to two Lower Moons.

This was bad. Yuichiro felt doubt creeping into his heart. Two Lower Moons, Six and Four. Just one would be a huge threat to any normal demon slayer; could they win against two of them?

“I don’t think it’s here for you, Kohaku,” Upper Moon Four said. “Look, it’s helping the slayer. The demon’s a traitor.”

Yuichiro’s grip on his sword tightened. Muichiro’s mist hovered around him and the top half of his brother’s body formed, teeth bared and glare fixed on the two demons.

“So what? All demons are the same! They’re all disgusting creatures that just want my blood!!”

“Disgusting?” Yuichiro repeated incredulously, trepidation giving way as his temper flared up. “Listen here, you old hag! Muichiro is the sweetest, nicest brother anyone could have! Why don’t you look in a mirror if you wanna see something that’s really disgusting!?”

Muichiro’s growls ceased for a moment as he looked at his brother with wide eyes. Yuichiro didn’t notice, gaze fixed on the enemies ahead.

“H-Hag?! How dare you!” Lower Six gasped. She turned to Lower Four with a petulant pout. “Mogura! Teach this brat his place!”

“Fine, fine, just stop whining, okay?” Lower Four sighed and raised an arm up. Five holes formed in his palm, and from those holes shot a volley of crystalline projectiles.

The twins were quick to jump out of the way, but as Yuichiro landed, a tree sprouted up beside him. The bark ripped itself open and a torrent of sap shot out. The young slayer was only just able to jump back in time as the sap splashed down where he’d been and solidified instantly.

Yuichiro pieced together the situation quickly. Lower Moon Six was using her Blood Demon Art to try and immobilize him in amber. If she succeeded, Lower Moon Four’s crystals would fill him with holes. Best not to let that happen, then.

“Mui, distract the ugly one! I’ll handle the big guy!” He called out to his brother before taking off.

“Ugly?! You little- Ah!” Lower Six didn’t get the chance to finish her tantrum as Muichiro sprang out from the mist. She shrieked and leapt away with surprising quickness, and Muichiro growled as he tried to chase her down.

At the same time, Lower Four knelt and slammed his hands on the ground as Yuichiro approached. “Blood Demon Art: Diamond Stalagmite!”

The ground vibrated beneath Yuichiro’s feet, and he leapt to the side as a spire twice his size burst out where he’d just been. He kept sprinting, but more spires shot out at various angles, making it hard for him to approach the demon. Two of them emerged from the ground in front of him, and Yuichiro ducked low before swinging his sword. He cut the crystals at their base and leapt through the opening as others closed in on the space he’d just occupied.

“Diamond Shower!” A flurry of small shards fired towards him, and Yuichiro shifted his stance.

“Mist Breathing, Third Form: Scattering Mist Splash!” His rapid swing blew away the oncoming projectiles. As the shards scattered around him, he glared at the demon with contempt.

“Hmph,” Mogura cracked his neck. “Not bad. You’re better than those weaklings from before, at least.”

“I don’t need praise,” Yuichiro growled. “Especially from someone who doesn’t even know his gemstones. Aren’t diamonds supposed to be hard? Those worthless rocks of yours are pathetically easy to cut through.”

He didn’t miss the way the demon’s eyes filled with rage. “Oh, so you’ve got a smart mouth on ya, huh? Good, I’ll take pleasure in shutting you up!”

Yuichiro opened his mouth, but then he heard Kohaku scream, and a strong smell filled the air, sickly sweet like honey. He chanced a glance to the other battle taking place.

Muichiro had landed a hit on the demon, her blood spraying through the air from the cut on her arm. But something was off. Muichiro’s mist returned to him all at once, and he fell to the ground, stumbling. He lifted his head and breathed in and out heavily. His eyes were blown wide, slit pupils becoming visible.

Yuichiro realized he had seen this before. “Muichiro, get away from her!” As soon as he spoke, he noticed movement in the corner of his eye and raised his sword. Lower Four’s stony fist collided with his blade and sent him skidding back.

“Figured it out, huh? Kohaku’s blood has the same effect as marechi blood,” Lower Four laughed. “Demons can’t resist the stuff; just a whiff makes them drunk out of their minds.”

“I know what it is,” Yuichiro growled. It was the same blood the Wind Pillar had tempted Muichiro with before. “But why aren’t you affected?”

“Ah, that. Well, turns out even after becoming a demon, I don’t have a sense of smell. Pretty inconvenient, but it ended up having its uses.” The demon smirked before attacking again, refusing to let up his close-range assault as Yuichiro dodged around each strike.

Muichiro noticed his predicament, and a bit of alertness returned as he tried to help. Before he could get anywhere, though, Lower Six raised her hands and a spindly tree grew and wrapped around him. Muichiro struggled against his bindings and his body seemed to waver, but it stayed together, unable to concentrate enough to use his Blood Demon Art.

Yuichiro cursed and feinted a swing at the demon. Lower Four raised his arms to block, but Yuichiro ducked underneath and sprinted towards his twin. His sword slashed out and cut the tree restraining him to pieces.

“Muichi- woah!” Yuichiro dodged out of the way of a drunken slash from his twin who failed to realize he’d been freed. The second he did, however, Muichiro lunged towards the Lower Six, claws lashing out in vicious, unfocused swings. All finesse or strategy was gone, replaced with a wild animal out for blood. The Lower Moon screamed as she barely dodged his strikes and threw out her arm in a panic.

“Blood Demon Art: Amber Grove Trap!”

Six trees burst from the ground, their bark splitting and spraying sap all at once. The sap hit its mark, hardening and freezing Muichiro in place. He snarled and thrashed about fruitlessly.

Yuichiro grit his teeth. This was getting worse by the second. The demon's marechi-like blood was driving Muichiro into a frenzy. He tried to switch targets to Lower Six, but more crystal spires shot out of the ground, and Yuichiro was forced to weave around them. Despite his best efforts, he was finding it harder and harder to even get near either demon. New spires blocked his path and forced him to move even as the old ones crowded him out. He needed to get rid of them, and the one creating them, now.

“Mist Breathing, Fifth Form: Sea of Clouds and Haze!”

Breathing in deep, oxygen filling his whole body, Yuichiro charged toward the Lower Four. His sword swung out against each crystal blocking his path, cutting them all down in an instant as he carved a path to the larger demon. Mogura's face was one of shock, not expecting the young slayer to gain such speed out of nowhere. Good, if he could take advantage of the enemy being caught off guard-

A tree sprouted up between him and the demon, and he instinctively slashed through it. Amber sap spurted out, covering his sword and solidifying instantly. The sap weighed his blade down, threw off his balance, but he was right in front of the Lower Moon. There was no other option; he finished his technique with a final swing at the demon’s neck.

Lower Moon Four grinned, and Yuichiro realized he had messed up.

His blade bounced off the demon’s armored neck, harder than stone, the recoil sending tremors through his body. His grip loosened and the sword flew off into the darkness. As he stumbled, balance lost, he saw the stake in the Lower Moon’s hand pulling back to strike.

Time seemed to slow. Yuichiro had time to think about his mistakes. The other Lower Moon had intervened because he turned his focus away from her. Thrown off by the unexpected attack, the angle he swung at had been all wrong to cut through the demon’s weakest point. And without his footing, he couldn’t get out of the way.

The stake stabbed through his side, and for a moment there was just shock. Then pain blossomed throughout his body, but he didn’t feel it for long. The force of the stake hurled at him launched him back, and Yuichiro felt his head collide with something hard before everything went dark.

—

As soon as Mui spilt the demon’s blood, the world tilted, becoming a blur.

He felt dizzy. He couldn’t process anything but that sweet, overpowering smell tinged with fear. The dizzying contradiction of rich blood he’d come to associate with humans and this demon that exuded it left him off-kilter, until he couldn’t tell up from down. She looked away from him, doing something, and Mui had used that distraction to rip free of the stickiness and leap at her throat. His teeth tore at syrupy sweet skin and tantalizing blood; the desire to devour it all was irresistible.

Then he heard Yui scream, and the world returned. Beneath the overwhelming sweetness, he smelled Yui’s blood.

Yui was hurt.

Mui released the Lower Moon and raced to his brother’s side. He saw the other demon standing over his twin, laying against a broken crystal with a stake pierced through his left abdomen. The demon had a spear raised to land the final blow.

“Yui!”

Mui leapt in without a second thought; he stood in front of his twin as the spear came down. The other demon was larger and taller, and his strength greatly exceeded Mui’s own. The spear pierced his torso with ease, but as it exited out his back, the pointed, bloodied tip stopped inches from Yui’s chest. Mui’s clawed hands gripped the shaft, arms shaking with the force needed to hold the weapon in place.

He looked back, desperately searching for signs of life in his brother. Yui’s chest rose and fell, slower than normal, and blood flowed sluggishly from his wound. He was still… so still.

Yui was hurt. Maybe even…

The fog crept into his vision, and he fought to push it back. He had to protect Yui! Get him to safety! But Lower Moon Four lifted the spear up abruptly, and the hole in his torso burned as gravity pulled down on him. Mui cried out in pain.

Mogura's eyes narrowed as they studied him before scoffing. “You both really are just kids, aren’t you? Always knew Ubuyashiki was sick in the head, but this is on another level.”

Mui wasn’t sure who he was talking about. He tried to get his breathing under control. He needed to focus! Or else Yui would-

“Look, kid, you don’t have to do this. You’re a demon; ain’t no point siding with demon slayers. Your brother, well, he’ll be dead before long, but you-”

Dead.

Mui froze, eyes wide with fear.

Dead. Yui would be dead. Yui would die.

He squeezed his eyes shut and shook his head. No. No!

Rage like a boiling geyser welled up inside him; barely contained and ready to burst. It felt familiar; this sensation- he wanted to make the demon hurt. He wanted to make it pay for hurting Yui. The heat surged through his limbs and drove away the fog creeping into his mind.

Fight!

You have to fight!

These monsters hurt Yui. Make them pay!

“Hm? What are you-” His arms shot out faster than Mogura could react, claws hooking into the armor covering his face. Yanking the demon’s face right up to his own, he opened his eyes.

Hollow turquoise irises locked onto the demon’s mismatched pupils, unwavering and inescapable. The effect was instantaneous as the Lower Moon’s eyes clouded over, his movements slowing and his will to fight weakening. Mui’s mist flowed around him, moving to enshroud the demon.

“Mogura!” An amber spear sailed past Mui’s face, cutting the bridge of his nose. The spell on the Lower Four broke, and Mui exploded into mist as the demon took a swipe at him. The cloud of mist rushed past the larger demon towards the smaller one, engulfing her completely.

Kohaku shrieked as the mist surrounded her. Small, half-grown trees sprouted up around her and spewed amber that solidified into a barrier of spikes. For a few seconds, there was silence but for the Lower Moon’s harrowed breaths and her partner’s muffled voice shouting beyond the fog. Then both of her arms fell to the ground. The rest of her hit the dirt next, Mui’s foot digging into her back, claws pulling at her hair and threatening to tear her whole head off. The scent of her blood reached his nose and he almost lost himself again, but sheer fury kept him rooted in the moment. He kept pulling.

“Mogura! Help me!”

A diamond spike pierced through the ground at an angle, drilling through Mui’s back and out his chest. The child demon cried out before his body burst into mist again. The mist condensed, the boy trying to recollect himself.

“Blood Demon Art: Crystalline Prison!”

The spike beneath Mui exploded, clear crystal rising up around him and enclosing him in a transparent sphere. He reformed his claws, preparing to slash through it, and that’s when the sphere suddenly closed in on itself. Its walls shrunk down within seconds, until Mui found himself in a space too small to even reform his head. He tried to slash with his claws, but without enough room to build up force, they slid harmlessly off the smooth surface.

“Try all you want, kid, but even a demon ain’t breaking out of that,” Mogura snarled. Lower Six gasped in relief and reached to reattach her severed arms, and the other demon stooped down to help her. “Hold on, I gotcha…”

Mui watched helplessly from inside his prison. He clawed uselessly at the crystal again, nails finding no purchase.

As soon as her arms were reattached, Kohaku strutted up to the sphere with her hands on her hips, full of undeserved bravado. “Hmph! See what happens when you mess with a Lower Moon, you brat?”

If looks could kill, and if he had a face right now, Mui’s glare would have disintegrated the demon on the spot. Unfortunately, all he could actually do was make a vulgar gesture with his claws. The Lower Six, easily baited as always, puffed up with indignation.

“You little- Mogura! Teach him a lesson!”

The Lower Four sighed, “Kohaku, will you grow up? Stop letting these kids get to you; it’s embarrassing.”

“Oh, shut up! Just kill this brat’s brother already, then leave him to burn in the sun!”

Mui’s churning mist froze. But fear quickly turned to anger again as he slashed futilely at his prison. Kohaku smirked, while Mogura rolled his eyes and marched towards the unconscious slayer.

Don’t touch him! Get away from him! He wanted to shout. He needed to protect Yui, but these walls held him back. His misty form swirled helplessly as the Lower Moon stopped and stared down at his brother.

“Sorry kid, but you brought it on yourself. Should’ve just lived a normal life.” He shook his head as a spear sprouted from his hand and he gripped it tight.

The anger flared hotter, and the young demon thrashed around in his cage, trying to break free, trying to release the fire that was burning him up inside.

“Just finish him off already, Mogura! I’m getting hungry!” Kohaku whined. Mui screamed soundlessly as he slammed a hand against the wall and raked his claws down, earning nothing but an ear splitting screech that reverberated through his prison. Kohaku jumped at the sound and fearfully backed away from the crystal.

The fire was all consuming now, but there was nowhere for it to go. He couldn’t get out. He couldn’t save Yui. Yui was going to die and all he could do was watch!

In the face of his helpless anger, an intense fear emerged. Mui was more scared than he’d ever felt before. Even the fear for his life, when Haru had swung his sword at his neck, could not compare to this. If Yui died…

If Yui died… Mui didn’t know what he would do. Yui helped him remember himself, helped him remember that he used to be human. That a part of him still was human. Yui gave him the strength to fight his hunger, his anger, and the fog always pressing down on him. Yui was his humanity. If Yui died, then Mui would be lost.

He couldn’t let that happen. But there was nothing he could do…!

Mogura raised his spear. For just a single moment, the rage and fear abated, replaced by pure despair. Please, someone…

“Remember this...”

Mui heard his Teacher’s voice. It was as if the gods had granted him a miracle.

“Demons… do not age. They do not weaken. They can grow… infinitely stronger. Master your breathing… Master your Blood Demon Art… And none… will stand before you.”

Breathing… the Lower Moon said even a demon couldn’t break this glass. But a demon who could use Breathing was even stronger. But this prison was so small; there wasn’t room to breathe in anything.

Except… except his mist could do it. His mist could absorb the cells of demons. It could absorb oxygen, too. It had to.

The mist expanded, swallowing up every bit of space within the hollow crystal sphere. Then it all condensed together into a slim, honed form, razor edged and sharpened to a deadly point. It pointed towards the moonlit sky, at a single hairline crack in his prison. A single flaw. A single weakness.

Mist Breathing, First Form: Low Clouds, Distant Haze!

The sword pierced through the crack, and the sphere shattered as a geyser of mist erupted skyward. It reformed in an instant, and Mui’s mist sword sliced through Kohaku’s neck before she even knew what happened. She let out a shriek as her head hit the ground, but Mui was already lunging for the other Lower Moon.

Mogura turned just in time to leap back as Mui’s sword swung at his neck, the vaporous blade cutting through the rocky armor protecting it instead. He crouched in front of his twin as the other demon jumped back beside his crying partner.

“Mogura! Mogura! He cut my head!”

“Get a hold of yourself, Kohaku! That wasn’t even a nichirin sword! It can’t kill you!”

Mui froze. He was right. Even if he could bring himself to use Yui’s sword, he didn’t know where it was, and he couldn’t look for it and fight them both off at the same time. He couldn’t kill them with his current abilities, either. His mist couldn’t dissolve them fast enough…

…But he could change that. It was as his Teacher said; he was a demon with infinite potential. All he needed was to want it with all his being.

A weapon to kill demons.

He breathed in deep, steeling himself. Yui, I will protect you, no matter what!

Mui returned to a neutral stance and raised the vaporous sword to eye level. Mist gathered around him as he brought his sword to his wrist and sliced.

A drop of blood rolled down and dripped into the fog.

“Blood Demon Art: Devouring Mist.”

The fire inside came to life within the mist, taking a form of its own. It turned the fog blood red and rose up behind him in a massive cloud, visages of snarling, ravenous beasts forming within before it rolled towards the two demons. Mogura shoved Kohaku away before jumping aside himself. The fog billowed past and caught his arm, and Lower Four roared as he pulled away with nothing but a bloody stump where the fog had touched.

Lower Moon Six was not so lucky.

The mist howled as it crashed down on her, gnashing teeth swallowing her up in an instant. Her screams cut off abruptly, the red color becoming even more vivid and grotesque. Then the roiling clouds receded, leaving nothing of the Lower Moon behind.

“Ko…Kohaku!” Lower Moon Four shouted in horror. “What did you-!”

Mui didn’t hear him. The red mist flowed back into his body, absorbing the demon’s blood to empower him. He braced himself, expecting it.

But he didn't expect the pain that came with it. Foreign. Excruciating. Like something was trying to dig its way inside. Mui felt like he was being crushed beneath the weight of a mountain. He doubled over, a glimpse of red, slitted eyes flashing through his mind. Something crawled under his skin and his nerves felt like they were on fire. He couldn’t breathe; his mouth opened in a soundless scream.

The Lower Moon’s blood carried something else: an ancient blood, a powerful blood. It rushed through him, searing his body from the inside out. It was a pain he’d never felt before; it burned until he feared it might burn him away completely. He turned, reaching a shaking hand out to his brother and pleading for help.

It hurts… Make it stop, Yui!

And then suddenly it did.

The young demon collapsed to the ground, gasping for air. The mist in his mind cleared, burned away by the ancient blood. It didn’t come back. His head shot up, and Muichiro looked at the full moon shining above. He stared, entranced. Had it always looked so bright?

A crystal stalagmite shot from the ground, and Muichiro struck out with a claw, shattering it to pieces before it touched him. The blood mist roared back to life, swirling protectively around him. His head dropped to glare at Lower Moon Four. The fog was gone, but he still saw red.

Make the demon pay.

“Huh? A demon crest-”

Muichiro moved, disappearing and reappearing in front of the Lower Moon in an instant. His claws lashed out, but Mogura smirked and raised his arm to block, the claws digging into the rock but not cutting. Then the red mist wrapped around Muichiro’s nails and began to melt through it, and the smirk vanished. The demon’s free hand swiped up and severed Muichiro’s arm at the elbow. The young demon stumbled back, the glare never leaving his face as he raised the stump of his limb. A cloud of sanguine mist poured out of the wound, engulfing Mogura’s upper body and causing him to recoil as his skin melted in the haze. He jumped back, out of the cloud, and the outpouring of mist stopped as the arm regenerated and Muichiro lunged forward.

A red fog sword formed in his right hand. Mogura’s crystal claws lashed out, impaling him through the stomach. But Muichiro was barely fazed; he snarled and stabbed the sword into the Moon’s side, the same spot in which he’d hurt Yuichiro. Lower Four howled, and Muichiro felt the ground shake beneath his feet. A sword formed in his other hand and he slashed through the demon’s arm before jumping away as a crystal pierced the spot he’d stood on.

He landed, and the ground shook again. Three crystals ran him through, one after the other, hoisting him into the air. Muichiro coughed blood, but despite the damage, he barely felt anything. All he felt was fire, and an aching void in his stomach that was steadily growing wider. It cried out, urging him to kill, to eat and grow stronger.

Mist poured from his wounds, dissolving the crystals down to nothing. Muichiro fell to his knees and shuddered as his body repaired itself. Then he lifted his head and screamed, and the mist rose up in a spiraling storm. The head of a sharp-toothed beast emerged, echoing his roar towards the sky.

With jaws open wide, the mist beast descended upon the Lower Moon. Panicked, the demon barely dodged in time, armor melting as it crashed down inches from him. Mogura tried to run, but the monster reformed and chased him down, swerving around to cut off his escape. It engulfed and dissolved the surrounding trees and rocks, uncaring of anything in its path. A second head lunged from the fog to rip through the demon’s legs. He fell to the ground, and the pursuing mist beast surged towards his vulnerable form.

But just before the jaws could touch him, the mist dispersed, scattering into the air. Muichiro was suddenly in front of Mogura, lashing out with a kick that threw him up in the air. He crashed down onto one of his own crystals, and Muichiro slammed down on his chest with a force that almost shattered it. Mist-covered claws cut through the Moon’s arms before he drove a fog sword through the demon’s throat. Mogura choked on his own scream, blood pouring from his mouth. The sword burned, rage and hate made manifest.

“Wha- what the hell?” He gurgled, lungs crushed within his caved-in chest. “Where'd… this power-”

A red flash, and suddenly his tongue and mouth split open, cutting him off. Muichiro stood over him, turquoise eyes glowering through the fog. The mist writhed as if it were alive.

Lower Moon Four’s face went pale, his eyes wide and pupils shrunken. Muichiro felt drawn to his numbered eye, bright and alluring, bearing the kanji for four. It made his boiling blood scream, the fire inside raging into an inferno.

Another mist sword formed in his hand. He raised it high in the air, then brought it down through the numbered eye. Lower Four tried to scream, but all that came bubbling out was more blood. Muichiro ripped the sword out, then drove it through his eye again. And again.

On the fourth stab, the crystal beneath Mogura rose up, forming an opaque dome around him. The sword pierced it with ease, but Muichiro didn’t sense it connect with the demon’s flesh. He growled and slashed through the dome, only to find it empty, a deep hole dug into the ground.

Muichiro took a step back, confused, until he heard movement behind him. He turned to see the Lower Moon holding an unconscious human, claws held against his throat. Muichiro didn’t recognize him.

Lower Four drew ragged breaths, his wounds already healing. “Don’t… don’t move!” His claws pressed against the human’s neck, the message clear.

For a moment, Muichiro stared. The mist settled as something in the back of his mind gave him pause, a brief lull to the flames rushing through his veins. A wisp of a voice, muffled, whispered to save the human.

“You…”

His face hurt suddenly. He closed his eyes and when he lifted his hand to his cheek, he felt it cracking. Like a spark to dry wood, the pain reignited the flames and smothered the voice.

All that mattered was killing the demon. A dying hostage wasn’t worth saving.

His eyes snapped open, slit pupils constricting. The blood mist flared, twisting together and forming the visage of a wolf-like beast. It opened its toothy maw and descended upon its prey.

“Muichiro!”

—

Wake up, Yuichiro! You have to wake up!

…Father…?

Consciousness returned to Yuichiro all at once. He opened his eyes, his vision full of red. The color and smell of blood invaded his senses. Yuichiro moved and pain immediately raged through his body. That’s right; they’d been in a fight, and he’d been injured.

But what happened after that?

Everything in front of him was shrouded in an unnerving bloody haze. It took him a moment to recognize that it was mist. He could barely see two dark shapes within the fog. Two voices screamed in rage and pain, both nearly drowned out by a roaring wind as the mist swirled violently.

Yuichiro’s hand patted the ground. His sword, where was his sword?! He looked around and spotted a familiar glint lying amongst a pile of shattered crystals. Slowly, agonizingly, he pushed himself to his feet, the wound in his side screaming in protest. Blood still oozed from it.

Come on, Yuichiro, you have to focus! Stop the bleeding with Recovery Breathing!

He struggled, but soon he could feel the blood flow around the wound slow down and then stop. It would work, for now. Finding his footing, he moved towards his sword. It took far too long for such a short distance, but eventually he reached it. With weapon in hand, he turned back towards the fog.

“Muichiro…?”

The red mist slowed and settled suddenly, hanging low to the ground. At first Yuichiro thought his brother might have heard him, but he soon realized that wasn’t the case. The battlefield was revealed, and he saw Lower Moon Four knelt on the ground, claws raised to an unconscious Hayato’s neck. Muichiro stood a good distance away, his face unnervingly blank. He seemed to be injured somehow, cracks and bruises spread across his cheeks and forehead. The strange red mist clung to him like strangling vines.

Yuichiro still wasn’t sure what happened, but he understood the situation in front of him. The Lower Moon was using Hayato as a hostage against his brother. He grit his teeth. Could the demon sink any lower?

“You…” Muichiro breathed out a single word, soft and full of loathing. The venom contained in that one sound was not something the older twin ever expected to hear from his sweet little brother. A chill ran down his spine.

That chill turned to icy horror as the mist around Muichiro erupted into the shape of a massive beast. It lunged for the Lower Four and Hayato with jaws opened wide.

“Muichiro!”

Yuichiro moved without thinking. He ran in and threw himself at his brother, knocking them both to the ground. The older twin cried out in pain; even though he had only touched the red mist for a moment before passing through, it burned like acid against his exposed skin. Deprived of its master’s focus, the mist beast swelled and burst apart harmlessly.

“Muichiro, stop!” He shouted as his twin screamed and thrashed around beneath him. It was taking all of his strength just to keep him pinned down. “It’s me! It’s Yuichiro!”

It worked. Muichiro freed a hand and swiped at him, but as soon as he heard his name, he stopped. His claws froze inches from his neck. Yuichiro looked down at his brother’s face, and his breath caught in his throat.

Am I dreaming? Is this a nightmare?

The cracks on his face had opened. Six glowing eyes glared up at him, pupils narrowed down to slits. What he thought were bruises were teal, cloud-shaped markings snaking across his cheeks and forehead. A deep fury marred Muichiro's face before his eyes went wide, recognition and horror filling them all.

“…Yuichiro?”

Chapter Text

Yuichiro couldn’t move, couldn’t breathe. He could barely process what he was looking at. Muichiro trembled as he stared back with too many eyes.

“…Yuichiro?”

Muichiro hadn’t called him by his full name ever since his transformation all those months ago. Why now?

“Muichiro, what happened to you?” His brother seemed to be back to his senses, so Yuichiro crawled back and allowed him to sit up. Muichiro did so, and the red mist crept in and wrapped around his limbs. His long hair fluttered on its own, rising and falling with the sanguine wisps.

Muichiro frowned, apprehensive. But then his eyes lit up, as if realizing something, and he smiled. “I got stronger. I remembered what Teacher told me, and I got a new power to kill the Lower Moon!”

Upper Moon One? He was responsible for this? Yuichiro looked warily at the unnerving red mist that lurked just out of reach like a waiting predator. But wait… did he say kill? Demons couldn’t kill demons, right? But he didn't see Lower Moon Six anywhere.

Muichiro kept smiling. “And not only that, but I remember! I remember everything! You, Mother, Father! The fog is gone!”

“You do…?” Yuichiro thought he should have been happy about that. Muichiro had his memories back, and was speaking in full sentences… but all he felt was unease. His brother’s eyes were bright and full of life, but they almost seemed to be looking past him, staring at something he couldn’t see. But looking too closely was fogging up his head even worse than usual.

“Uh huh! Isn’t it great? Now I can finally be equal to you!”

“Equal?” Yuichiro blinked and shook his head; he was getting distracted. “Muichiro, listen. I’m glad, really! But you need to stop this!” He gestured to the mist around them. “Something’s not right!”

“Huh?” Muichiro blinked, suddenly looking dismayed. “What do you mean? Aren’t… Aren’t you proud of me?”

“Proud of you?” Yuichiro repeated, horrified. “Do you know what you just did?”

“I killed a Lower Moon! All on my own!”

“No, you almost killed a human!” His voice was rising, but he couldn’t stop it. Fear gave way to anger. “If I hadn’t stopped you, you would have murdered Fujimoto! Don't you understand that?!”

Muichiro froze. He looked shocked, like he truly hadn’t realized that. His next words were said in a small, devastated whisper.

“If you hadn’t stopped me…?”

That was not the answer he’d expected. Yuichiro suddenly felt he had said something he shouldn’t have.

“Muichiro?”

--

Muichiro didn't understand. He couldn't understand.

Hadn’t he done everything right? He listened to his Teacher’s words and obtained greater power. He killed a Lower Moon. He protected his brother.

So why was Yuichiro looking at him like that? With anger and fear? What had he done wrong?

“Is… Is that what you think of me? Am I just a monster you have to keep under control?” His voice was shaking, verging on tears. He felt pathetic, but he couldn’t stop it. “And after how hard I fought to protect you?!”

“Of course not!” Yuichiro gasped. “But, that’s not-!”

“Shut up!” he screamed, startling him into silence, startling even himself. “I saved you! I saved so many people that the demon would’ve killed! But all you care about is one person who's already dying! Why?! You’re my big brother! You’re supposed to be on my side!”

Because he doesn’t care about you.

He froze. Whose voice was that? It didn’t sound like Yuichiro or Teacher. Was it his own? But it was so cold. The voice sent tremors through his whole body, its words reverberating from his mind down to the core of his being.

Yuichiro… didn’t care about him? No, that couldn’t be true! But then why was he still looking at him like that? Why wasn’t he proud of what he’d accomplished?

“I am on your side!” Yuichiro’s words rang hollow in his ears.

“Then act like it! Tell me you’re proud of me! Tell me I did good!”

Just say something!

But Yuichiro didn’t say anything.

He never cared about you. Not back then, and not now.

Back then…? Memories, unbidden, began to flood his mind, of a year spent in hell. All alone, with a brother who hated him. Who always insulted him, who always put him down. No matter how hard he tried to be better. Incompetent. Meaningless. Nothing.

Yuichiro didn’t care about him.

Subconsciously, coils of red mist reached out towards his brother, pleading, begging him to prove the voice wrong. They reached for him, and Yuichiro stepped back, fear in his eyes.

Something in Muichiro broke. Unrestrained, fire filled his veins, his head, his soul. The voice whispered the truth.

You’re nothing to him.

--

He hadn’t meant to. But he was scared; he couldn’t deny that. Muichiro was acting so strangely. He’d never yelled like this before, so hysterically, like the world would end if he didn’t get what he wanted. But Yuichiro had no idea how to respond to his demands. He was asking for something he couldn’t even understand, let alone give.

And then the red mist reached out, and Yuichiro knew firsthand how dangerous it was. Survival instinct kicked in, and he took a step back. He hadn’t meant to.

But he knew as soon as he did that he’d made a mistake.

Muichiro lowered his head, his hair obscuring his face. The red mist fell low to the ground. He didn’t say anything at first, but Yuichiro could see him trembling.

“You don’t… you don’t believe in me. You’ve never believed in me! Nothing’s changed! I’m still not good enough for you!”

“Muichiro, what are you talking about?” Yuichiro was reeling mentally; this was all happening way too fast for him to keep up.

“Don't play dumb!” His head shot up, revealing the tears streaming down his face. “How could you not know?! You said it so many times! The Mu in Muichiro stands for incompetent! It stands for meaningless! Don’t tell me you don’t remember saying that?!”

Yuichiro’s thoughts grinded to a halt. Maybe this really was a nightmare; it felt like all his worst fears were coming true at once. “You… you remembered?”

“Of course I do! How could I ever forget? You-” Muichiro turned away, seemingly unable to look Yuichiro in the eyes. But his bottom set of eyes glanced right, and suddenly his head snapped in that direction. “Don’t run, you coward!”

Yuichiro followed his gaze to see that the Lower Four had abandoned Hayato and tried to sneak away while they were distracted. Muichiro looked furious as he raised a hand and the surrounding mist flared up and lunged for the demon. It ripped through his arms and legs before settling upon him like a swarm of flies. Lower Four screamed as it ate away at his flesh.

Yuichiro jumped. That mist tore through a Lower Moon, one of the Twelve Demon Moons, like he was nothing. But it wasn’t actually killing him, just causing pain as his flesh melted and regenerated over and over. It was torture for the sake of torture. Muichiro had always fought viciously against demons before, but never like this.

“Muichiro,” He didn’t respond, still focused on the Lower Moon. Yuichiro took a deep breath to slow his racing heart and tried again. “Muichiro, stop this-”

Three of Muichiro’s eyes snapped towards him. The rest followed as he turned his gaze, still in tears but burning bright with rage. “Stop? Why? He hurt you! This is what he deserves!”

“I know that!” And Yuichiro would be lying if he said the demon didn’t deserve it, but… “But I don't want to see you doing this to him. It’s not right!”

“Not right? And I guess suddenly you know what’s right, huh?” Muichiro snapped and stood up. The mist whirled wildly and his tear-filled eyes glared down at him. “Oh, but you’ve always known better! That’s why you said those things! Because I’m your stupid little brother who can’t do anything on his own!”

This was really happening. Muichiro had his memories and consciousness back. Yuichiro had his brother back. How had their reunion ended up like this? With his heart paralyzed, Yuichiro’s rational mind tried to regain any control he had over the rapidly deteriorating situation.

“Muichiro, this isn’t the time! We’re not safe here!” He stood up and tried to get closer, but the blood mist hissed at him to stay back.

“No! If the demon moves, I’ll kill it! But you’re not running from this! That demon didn’t hurt me; you did! You made me feel like I was worthless! Like I couldn’t do anything without you! What kind of big brother does that?! Do you hate me?! Is that it?!”

“No! I could never hate you!” And Yuichiro meant that; he really, truly did. But Muichiro was beyond listening at this point.

“Then why?! What were you trying to do by telling me that my name meant I was nothing?!”

Silence fell. Muichiro waited for an answer, but Yuichiro couldn’t say anything even if he wanted to. Because it was true. He had wanted Muichiro to feel like he couldn’t do anything, so long as he wouldn’t put himself in unnecessary danger. So long as he stayed safe by his side. He was prepared for the possibility that Muichiro would hate him for it. Or at least, he thought he was prepared. But the actual reality he was facing now was much more painful than he could have ever expected.

His lack of response seemed to only upset Muichiro further. His six eyes narrowed and he opened his mouth to speak, when suddenly he squeezed his eyes shut and curled in on himself. He hissed and clutched at his stomach. More of the red mist rose from his body.

“Mui? What’s wrong?” Yuichiro jumped, panic seizing his heart. “Are you hurt?”

“It’s nothing!” Muichiro growled even as he winced and shuddered through another wave of pain. “Don’t try to distract me!”

“Distract you?! Muichiro, you’re hurting! We can deal with… we can talk about that later! We need to get you help first!” Yuichiro felt bad for seemingly brushing off his brother’s feelings, and he was certain Muichiro thought he was doing just that. But this was not the right time to talk about this. “It’s not safe here! The Lower Moon-”

The Lower Moon was gone. There was a hole in the ground where he’d last been. Muichiro stared at the spot, wide eyed and disbelieving, before he suddenly screamed, an inhuman roar of pure fury coming from his throat. He turned, glowing eyes locking onto his brother, and Yuichiro was stunned by the hostility in his gaze, as if he were no different than the Lower Moon. In his brief hesitation, Muichiro moved faster than he could react, lunging and slamming him to the ground. Clawed hands grabbed him by his collar and pulled him up inches from his twin's face.

“This is all your fault!” Muichiro screamed. “That demon’s going to kill more people now! I could have stopped it if you hadn’t gotten in the way!”

“You… were going to kill... a human!” Yuichiro looked into his eyes, trying to fight through the fog forming in his head to maintain eye contact. He needed Muichiro to hear him.

“That human is already dead! It wouldn’t have mattered! But I would have rid the world of another despicable demon!”

Shock briefly pushed the fog back. Hayato was dead? But Yuichiro forced that aside and focused on what he needed to say now. “It… does matter…!”

“And why is that?!”

“Because… I know you.” The fog was getting thicker; he could barely focus on his brother’s face right in front of him. He could barely think about his next words. “You’re not… a monster… and the Muichiro I know… and love… would try to protect human life… no matter what.”

He heard Muichiro gasp. The grip on his collar loosened, and the fog suddenly cleared as their eye contact broke.

“…Love…?” Muichiro looked shocked, but it soon passed, and the anger returned. “No, you’re lying! You’re just saying that-!”

“I’m not!” Yuichiro yelled, still shaking off the lingering fog. “I know I said so many awful things to you, but I promise you, Muichiro, I’m not lying about this!”

Muichiro searched his gaze, looking for any sign of deception, but Yuichiro held firm. Slowly but surely, realization crept into his eyes, slit pupils expanding. “You’re… You’re really not…” His shaking hands released their grip on his collar. Muichiro tried to stand up, only to lose his footing and fall. Even still, he crawled back, away from Yuichiro. His six eyes looked around frantically, eventually settling on Hayato’s still form. They widened, horrified. “What… What am I…?”

He winced and curled in on himself again. The red mist wrapped protectively around him like a shell, or maybe more like a comforting blanket.

Yuichiro sat up and shook away the last of the fog. He tried to get closer, but the red mist lashed out protectively. Snapping teeth caught the tip of his fingers, and he pulled back with a shout, the stinging sensation lingering.

Muichiro startled and crawled further back. The mist flared up again. “Stay away from me!”

“No, I’m not leaving you like this!”

“And why shouldn’t you?!” Muichiro successfully got to his feet and backed further away from his brother. The fog was now so thick that nothing but his glowing eyes could be seen through the haze. “I can’t be like you! I was stupid to think I could ever be like you! Because I’m not human! I’m a demon, a monster!”

As if reaching a crescendo, the blood mist swelled and erupted, lashing out in all directions. Vicious tendrils scored gashes in the ground and tore through trees with reckless abandon. But they didn’t touch Yuichiro or Hayato. Was that luck, or was Muichiro trying not to hurt them? Whatever the answer, the surrounding landscape was decimated in mere seconds, burned and lifeless like the aftermath of a fierce wildfire.

After a full minute, the storm slowed and settled back to the ground. Muichiro was breathing heavily, one hand clutching the fabric over his heart while the other gripped his stomach. He lurched forward, clearly in pain.

Yuichiro didn’t know what he could do. But he had to do something, because he couldn’t stand to see his twin in so much agony. Even if he himself was the cause of so much of it. He stood up, slowly and obviously, so as not to startle Muichiro. Then, one step at a time, he closed the distance between them.

“Muichiro?” His brother didn’t answer, still gasping for breath. He looked awful; his skin was pale and his whole body was shivering. But demons didn’t get cold, right? “Muichiro, look at me.”

Muichiro shuddered and lifted his head, six eyes silently glowering. His gaze shifted to the sword in his hand, then back to his face. When he spoke, his voice was disheartened. “…Are you scared of me now, Yui?”

Yuichiro’s eyes narrowed. He knew the answer to that. “No.”

He let his nichirin sword fall to the ground. Muichiro stared at it, shock clear on his face. “Why? What if I attack you again?”

“I don’t think you will,” Yuichiro crossed his arms. “And even if you did, I still wouldn’t hurt you. You’re my brother, Mui.”

“Really? You’re saying that now?” Muichiro asked bitterly. “After everything you’ve done to me, now you’re saying you actually care?”

Yuichiro looked away. Muichiro’s doubts were a reminder of how utterly he’d failed at being an older brother. But he wanted to be better, and he couldn’t do that if he let his own doubts hold him back. He looked back, his gaze resolute. “Muichiro, I know my words don’t mean much to you right now, but please listen. You’re not a monster. You’re the kindest person I’ve ever known. Who else could become a demon and still try to protect humans? How many demons have existed over the past thousand years, and you’re the only one to never eat a human? Doesn’t that mean something?”

Muichiro was silent for a while before he spoke. Sadness crept into his voice. “…It doesn’t mean anything. The moment you got hurt, I lost control of myself. I would’ve killed Fujimoto and not cared at all.”

“But that’s not your fault. And I shouldn’t have made you think that it was. I’m the one who got hurt and forced you to use this power. You didn’t do anything wrong.”

Muichiro looked away, his eyes watery. The anger was still there, but he slumped with exhaustion. “Yuichiro-”

“I promise, we’ll talk about this! We’ll talk about everything! But not here!” His wound stung horribly, and he felt like he could collapse at any moment. And Muichiro didn’t look any better. “I just… I just want to go home. Let’s go home, please?”

—

Let’s go home, please?

Muichiro wanted that. He was so, so tired.

Why was he so angry, anyway? The current Yuichiro and the Yuichiro from his childhood were overlapping in his mind’s eye. All the memories he regained were confined to his last year of humanity. He couldn’t stop thinking about the pain he’d felt; the fire burned away everything else. And the voice -his voice?- was still there, taunting him with his darkest thoughts.

Home? You have no home. A demon can’t live amongst humans.

Don’t listen to him. He’s lying to you.

He knows you’re stronger than him. He’s only trying to placate you to save himself.

…Was this really his voice? It didn’t sound like him. Was it because he was a demon now? This anger didn’t feel like his own.

In fact, his entire body didn’t feel like his own. The blood mist that helped him fight the Lower Moons was now draining every bit of strength he had to keep itself alive. The fiery anger that guarded his heart was burning him out, leaving him hollow. But his body was as tense as ever, as if lightning was running through his nerves. As tired as he was, his mind was alert to every scent and sound within range of his senses. It was all too much.

The hollow ache in his stomach clawed persistently at his mind, begging to be satisfied. Each time it went unanswered, pain lanced through his body. He needed to eat.

A glint on the edge of his vision caught his attention, and he looked at Yuichiro’s blade on the ground. A white blade that reflected his face. His six eyes went wide.

Is that… me? Since when…

He looked back at Yuichiro. His eyes saw past his clothes and skin to the muscles and bones underneath, to the blood pumping through his heart. He saw everything that came together to create a human being. But the more he looked, the less he saw the actual human. He wasn’t looking at something alive with thoughts and feelings, but a vessel of meat and blood for his teeth and claws to tear apart.

Why should a predator care about its prey? Humans are food. Eat, and grow stronger.

No, that’s not food! That’s Yuichiro! But no matter how his rational mind screamed, he couldn’t ignore his hunger. His heart thundered in his chest and his breathing became fast and shallow. He was starting to panic, and the blood mist responded to that. It rose up around him, thrashing and biting at the air, trying to protect him even as it made everything worse.

“Muichiro, you have to stop this!” Yuichiro shouted over the sound of the rushing wind. The sanguine haze forced him back. “Shut it off!”

“I… I can’t!” Muichiro cried. He squeezed his eyes shut. “I can’t control it!”

The mist seemed to respond to his emotions, but he couldn’t calm down. Anger and fear and the ever present hunger blurred together, indistinguishable from one another. And just when he thought it couldn’t get any worse, he felt something warm and strong wrap around him. His eyes snapped open, and he found himself in Yuichiro’s arms, held tight against his body.

“What are you doing? Get away! I’ll hurt you!”

The red mist swirled violently around them. He struggled to force it away from his brother, to keep it away from his wound. That crystal stake was the only thing keeping him from bleeding out; he couldn’t let the mist destroy it. No matter how angry he was, he didn’t want to hurt Yuichiro. Never Yuichiro. Muichiro tried to push him away, but couldn’t muster the strength to do so.

Yuichiro spoke, his voice calm and clear even with the roaring in his ears. “I won’t. You’re my twin brother, and I won’t leave you to suffer all alone. You said you wanted us to be swordsmen and save people together, right? Well I want that too. And that means both of us have to get through this.”

“Don’t be stupid! I told you that I can’t control it! You’ll die!”

Yuichiro shrugged. “Well, I guess you’ll just have to figure something out before I die then.”

Muichiro wanted to scream. Idiot! How could he have any trust in him after all this?! Even now, he was only barely resisting the urge to bite down on his twin’s exposed neck. At any moment, he might lose control, and he wouldn’t be able to stop himself in time.

Yuichiro had been right all along; he was nothing. He was worthless, incompetent, helpless to fight his own instincts. He couldn’t do this!

The mist responded to his racing heart, picking up in ferocity. If this kept up, Yuichiro was going to die, melted down to nothing by his own brother’s power. Muichiro’s body was stuck in a perpetual fight-or-flight mode. It was tearing itself apart trying to sustain this deadly power, unable or unwilling to recognize that Yuichiro was not a threat. And the more the blood mist surged, the more exhausted he became, and the more the hunger screamed to be satiated.

What would happen if he lost control? There was an entire town at the base of this mountain! What would he do to the humans there?

Yuichiro’s words came back to him: the Muichiro I know and love would try to protect human life… Tears blurred his vision.

No… You’re wrong about that. I haven’t protected anyone. Kasumi got hurt and lost her legs. Hayato got hurt and lost his life. Even you got hurt, when I should have kept you safe. I haven’t protected anything that matters.

Pain ran through him once again, sharp and aching. He struggled to hold onto his rationality as animalistic hunger tore at his mind. He heard Yuichiro bite back a scream, and felt something warm and wet soaking his hands. Horror filled him as Muichiro pried open his bloodied claws from their death grip on Yuichiro’s back.

You can’t save anyone. Give up and accept your nature.

The voice was louder than ever, carrying a compulsion that took all his will to resist. He needed to stop this.

I’m sorry, Yui…

Muichiro wasn’t strong enough to fight the demon inside. The mist in his head had always done that for him. He needed it back. With a shuddering breath, he willed it to rise up, the mist that swallowed up his memories and emotions and everything that made him him. It billowed and roiled, slowly engulfing all of it.

As the fog grew thicker and thicker still, he tried to focus on his twin’s warm embrace. Had his brother ever hugged him this gently before? He was sure that he must have, during better times, but he couldn’t remember. Why couldn’t he remember?

But it didn’t matter now. Muichiro closed his eyes, and he vanished within the endless mist.

—

Yuichiro felt something change. The violent red mist faded back to the usual calm white, then vanished entirely, revealing the ruined forest around them and the moon overhead. The exposed skin of his hands was red and raw from the fog, and he assumed his face must look the same. The crisp night air stung at first, but it soon turned into a welcome relief from the prior heat.

“…Mui?” he called softly. Muichiro didn’t answer, so he loosened his hold and pulled away. Muichiro was staring at the ground with a lifeless expression. The extra eyes and cloud-like markings had disappeared, but the eyes that remained were dark and empty. Even their natural glow had dimmed.

“Muichiro?” He called again. He grabbed and shook his arms lightly, biting back a curse as he did so; it hurt to touch anything. Upon hearing his name, his twin slowly looked up and opened his mouth to speak.

He didn’t get the chance before a crystal javelin bored through the back of his head and out his right eye. Yuichiro froze, his face and uniform suddenly covered in his brother’s blood and bits of bone and viscera. He could only stare at the bloodied spike protruding from Muichiro’s face, his remaining eye wide and uncomprehending. Then Muichiro lurched forward into his arms as five more crystals dug into his back. Finally, Yuichiro found his voice and screamed.

“Muichiro!” He dropped to the ground, laying his twin down and trying not to hurt him any further. But he was a demon, so he’d be okay, right? No matter how gruesome it was, something like this couldn’t kill him. But why wasn’t he regenerating? Why wasn’t he turning into mist to escape?

Lower Moon Four stomped towards them, heaving with fury, and Yuichiro was genuinely stunned to see him. Had he come back? Or had he never left at all, biding his time for a chance to strike? “That… monster… needs to be staked and left for the sun!”

The shock of the moment was passing, allowing him to think clearly again. But as soon as the Lower Moon said that, a fire surged in the pit of Yuichiro’s stomach. His face contorted in rage. “Don’t… Don’t you dare talk about my brother that way!”

“Don’t be stupid! That thing’s a threat to everything, humans and demons. The Demon King should’ve-”

“Shut up! He stopped himself, didn’t he?! He regained control of himself! That’s more than any of you can say!” Yuichiro screamed. “You can think and feel; you could’ve stopped and changed at any time! You chose to keep killing humans for some meaningless rank! You’re the monsters!”

“You-! That thing killed Kohaku!” Lower Moon Four took a swipe at him, but Yuichiro was ready. He ducked and leapt for his sword on the ground, grabbing it and rolling into a low stance. His wound screamed and the raw skin of his hands protested even holding the hilt, but adrenaline and fury were pumping through him, dulling all his pain to a faraway throb.

“Do you know what I had to do to protect her?” Mogura screamed, continuing to lash out. “Every demon for miles wanted her blood! I was the only one who could keep her safe! This was the only place we could go!”

Yuichiro dodged and deflected each strike. His wounds made it hard for him to move quickly, but the demon was slower too. Demons didn’t get tired normally, but his fight with Muichiro had somehow worn him down. Even his armor was cracked and melted in multiple places.

Yuichiro swung his sword and knocked the demon’s incoming fist away, then leapt back to distance himself. “Yeah? Sorry if I don’t have any sympathy for you and your man-eating girlfriend!”

Then for some reason, something Tengen joked about a couple weeks ago came to mind. He hadn’t understood the joke then, and he still wished he didn’t now. It was low, vulgar; was he really going to…?

…Yeah, he was.

“Oh, but, speaking of man-eater-!” Yuichiro leapt into the air as the ground shook and a horde of stalagmites impaled his previous location. Okay, he deserved that one.

But he had certainly succeeded in pissing the demon off. “You… You two ruined everything!”

Yuichiro landed where the tips of the stalagmites converged, looking down on the demon. He gripped his sword tight as focused rage boiled up inside him. He breathed deep, strengthening his wounded body; he could do this.

“I’m fine with that; you can find your girlfriend again when I send you to hell. Because you were dead the moment you hurt Muichiro.”

Lower Moon Four roared and leapt up high into the air. Yuichiro watched as the demon came down, shadowed by the light of the moon. He steeled himself, kept his breathing full and steady.

Don’t falter. Don’t hesitate. Put everything you have into this technique.

The Lower Moon dropped closer, crystal covered fist pulled back to strike.

Become like mist and vanish!

“Mist Breathing, Seventh Form: Obscuring Clouds, Despondent Haze!”

Lower Moon Four crashed down with all the fury of a meteor. The cluster of spires beneath him were pulverized instantly, a cloud of dust scattering, but Yuichiro had already disappeared. From the demon’s perspective, it was as if he had never been there at all, a mirage in the mist.

“What…?” Lower Moon Four looked around wildly. Then he lurched forward and screamed as a long shard of splintered crystal was suddenly driven through his ankle.

“I see, so your armor can be pierced by your own attacks,” Yuichiro’s voice came from his left. “Not very smart, if you ask me.”

The demon growled and fired off a burst of crystals at the boy, but they simply went through him, dispersing the illusion. In the next instant, another crystal splinter went through his other ankle, and the Lower Moon fell to his hands and knees. The demon looked around, trying and failing to keep track of the slayer. A thick fog pressed in on all sides.

“What… what the hell is this?”

He was confused; good. Yuichiro had based this technique off his brother’s Blood Demon Art, after observing the way he moved in the mist, hiding and striking quickly before hiding again. If Yuichiro could learn to vary his movement and attack speeds, make himself unpredictable, then he could trick his opponent into lashing out at the wrong time, leaving themselves vulnerable.

Like now.

Another crystal was driven through the demon’s hand and into the ground. The demon’s own weapons had no issue breaking his armor, and there were an awful lot of them scattered around from his reckless attacks. The Lower Moon was panicking now, and as Yuichiro appeared in front of him with another shard in his hand, he lashed out.

“Diamond Stalagmite!” A ring of crystals burst out of the ground to form a protective barrier around the demon. But again Yuichiro leapt out of the way with unexpected speed, vanishing back into the trees.

“What…! S-stay back! Get away from me!” the Lower Moon suddenly shouted. Yuichiro thought maybe he was scared of him at first, but he quickly realized that wasn’t the case. Mist, real mist, was forming around the demon, crawling up his pinned form. It was white, not that awful red, but the demon still seemed terrified of it.

Yuichiro was behind the Lower Moon now, and he looked past him to his brother, lying on the ground, facing them with the javelin still stuck through his head. One arm was raised shakily, his remaining eye staring directly at him.

Yuichiro knew what to do. He nodded his thanks and steeled himself before jumping in, landing on the stalagmite directly behind the Lower Moon. It was there that he noticed the large crack on the demon’s armored neck. Was that from his fight with Muichiro, or had it always been there? Either way, it didn’t matter. “I told you, didn’t I?”

The demon startled and finally ripped the crystal stake out of his hand. He twisted around and swung at Yuichiro with outstretched claws, but the young boy had already jumped over him. He flipped and spun himself around, sword cutting through the air and towards the demon’s neck.

It was over in a flash. Lower Moon Four’s head fell to the ground, cleanly cut at the neck. His expression was one of silent disbelief. Yuichiro’s feet touched the ground, and he looked back at the demon with a look of contempt. “You were dead the moment you hurt Muichiro.”

“…Ko…haku…” the demon closed his eyes as he burned to ash. Yuichiro looked down and saw that the stake lodged in his side was also disappearing. Wait, that wasn’t good, was it?

As if the realization had unlocked a floodgate, a wave of pain and exhaustion fell over Yuichiro all at once. He gasped and fell to the ground, limbs suddenly heavy as lead and unable to support his body.

Come on, breathe! You have to stop the bleeding…

It was no use. He couldn’t get a handle on his breathing. Darkness was rapidly filling his vision.

“Ugh… Damn it…”

Was he going to die here? He doubted help would come fast enough before he bled out. The last thing Yuichiro saw before his vision went dark was the feet of a figure dressed in ghostly white, steadily approaching. He looked up to his own face staring impassively down at him. Then everything faded away as his mind slipped into unconsciousness.

Chapter Text

For Kokushibo, being summoned to the Infinity Castle was rarely a cause for concern. It didn’t happen often; his relationship with Muzan Kibutsuji was strictly professional, only being called on for tasks that would benefit the both of them. Most other times, he was left to his own devices, searching for the Ubuyashiki Estate or the blue spider lily. Being summoned was always abrupt, but he was rarely concerned when it happened.

This time, he knew, there was much to be concerned about.

The twang of a biwa accompanied his arrival in a small, lantern-lit room. Shelves of books and papers lined the walls, various lab tools and containers scattered on the tables. And at the other end of the room…

“Kokushibo.”

His master’s voice was harsh. Muzan turned to face Kokushibo, red eyes narrowed in displeasure. Kokushibo did not allow himself to show any fear; Muzan was often angry about his and the other Moons’ failures. But he knew that was not what his lord was angry about this time.

Muzan turned back to the desk in front of him, eyes returning to the book he’d been reading. “Lower Moons Six and Four are dead.”

Kokushibo didn’t respond. He had known about those two working together for mutual protection and had idly wondered if it would help them stay alive against the Hashira, but it was clear it did not. But why tell him this? He waited for his lord to continue.

“They were killed by the two children you allowed to live. By the demon you turned and left alone. It appears the child developed a Blood Demon Art capable of destroying a demon and absorbing their power.”

Kokushibo did not flinch. The only sign he felt anything was the tiniest raising of his eyes.

“As the first Upper Moon, I afford you many privileges, with the expectation that you will act by my will at all times. So tell me again, Kokushibo, why you spared those children. The boy should have devoured his brother. Instead he’s started eating other demons. And more than that, you left him alone long enough for Ubuyashiki and that wretch Tamayo to reach him. You are not usually one for such errors in judgment. What happened?”

“The boy had much potential… as a swordsman. I wished… to cultivate that potential. It surprised me as well… that he did not attack his brother… when he first turned.”

“And why did you leave them alone? If you wanted to train the boy, you should have taken him under your wing and killed the human. And what of the week you spent training him? An ideal opportunity, and yet you still allowed him to return to the Demon Slayers.”

Kokushibo said nothing; he did not have an excuse. On a whim, he had gone searching for traces of the Tsugikuni family, the family he’d left behind, and found himself on the mountain where those children lived. Although the Tsugikuni name was lost, the twin boys were nonetheless his descendants, the last remnants of his bloodline. The sight of them brought back memories he had long tried to bury, and seeing them continue to care for each other, despite being a human and a demon… He simply could not bring himself to separate them.

Kokushibo knew that Muzan knew this; he could see into his mind as easily as the open book in his hands. The Demon King turned his nose up in disgust. “Your lingering humanity weakens you, Kokushibo.”

Kokushibo’s body tensed. Anger flared, but he pushed it down. Because his lord was right. Sentimentality alone had led to this situation.

“…I do not care about the deaths of those two. The Lower Moons have been disappointing me for a long time now.” He glared back at Kokushibo. “But loss of control is not something I tolerate lightly. And if something goes out of control, then I expect it to be brought back into line, before it becomes a problem. Do you understand, Kokushibo?”

The first Upper Moon nodded and bowed. “I understand, my lord.”

Indeed, he had much to be concerned about now.

—

Yuichiro found himself in a thick white mist. He couldn’t see anything; not his hand in front of his face, or his feet on the ground. He wondered if there was a ground, or if he even had a body at all. Maybe he was just a ghost.

“Muichiro?” He called out into the mist. The clouds swallowed up his voice. Where was he? Was he dead? Was this the afterlife? He’d always thought he’d see his mother and father again when he died. This empty, endless fog felt more like hell.

No, he didn’t want to think about that. Yuichiro knew he wasn’t a good person, but…

A sound interrupted his thoughts. Thumping, rhythmic. The sound of a heartbeat.

Thump. The mist turned red. Burning heat and the smell of blood assaulted Yuichiro’s senses. He heard growls and snarls and a roaring wind picking up. He was wrong; this was the real hell.

Something moved behind him. Yuichiro turned.

Six turquoise eyes glowed through the red haze. With a roar, they opened wide and lunged.

—

Yuichiro woke up. The mist was gone, his vision clear. But it took his mind a few moments to process what he was seeing. He was in a dark room, staring up at the ceiling. The softness beneath his head and body told him he was in a bed. His face itched; he raised a hand to scratch it, only to find said hand covered in bandages.

The sound of footsteps shuffling nearby caught his attention. Slowly, Yuichiro turned his head to see a girl with familiar butterfly hair clips at his bedside.

“Kanzaki…?” Yuichiro mumbled. The girl had her back turned to him, but as soon as he spoke, she jumped and whirled around to face him. Shock colored her face as the two of them simply stared at each other for a while.

“Y-You’re awake!” She finally gasped out. “Oh, thank goodness! I was so worried!”

“You were worried? About me?” Yuichiro asked. If Aoi was here, then he must be at the Butterfly Estate. Had he been injured? His mind was still foggy with sleep.

“Of course I was! You’ve been asleep for three days since the mission at Mount Takao!” Aoi snapped with tears in her eyes. “You lost so much blood… I… I really thought…”

Was she really crying over him? Well, she’d been a bit of a crybaby during Final Selection, too. Yuichiro’s eyes then went wide as he registered what she said. He’d been asleep for three days? And Mount Takao-

Suddenly the memories flooded back. Hayato and the slayers killed in the amber, the two Lower Moons, and-

His heart stopped.

“Where’s Muichiro?!”

At his question, Aoi’s teary expression suddenly turned dark. She hesitated, then pointed past his head. “He’s… over there.”

For a second, Yuichiro forgot about his wound as he twisted his body to look in that direction. The sudden screaming pain didn’t hesitate to remind him, but he couldn’t care less. Relief filled him at the sight of two familiar turquoise eyes huddled in a corner of the room. They didn’t blink, simply staring as he straightened out his body in an effort to make the pain stop.

“Muichiro, you’re okay,” he gasped out, trying to force a smile. But Muichiro said nothing. He just continued to gaze impassively in his direction. Yuichiro’s smile slipped.

Behind him, Aoi wrung her hands nervously. “He hasn’t moved from that spot since you were brought here. He carried you right into the town at the base of Mount Takao; he didn’t even try to hide himself. We’re lucky that the owners of the Wisteria Inn were able to bring you two inside before anyone saw him and freaked out.”

Yuichiro was grateful for that as well. He couldn’t begin to imagine how that situation would be explained to ordinary people. “Was he like this then, too?”

Aoi nodded. “He doesn’t say or react to anything, but he refuses to leave your side. That’s why we covered all the windows. We thought he might be hungry, but he wouldn’t leave to go hunt, either.”

“He wouldn’t?” Yuichiro asked, surprised and worried. Muichiro had not been in good shape when he’d lost consciousness on the mountain. He always became unresponsive when he was starving, so was that happening now? But why wouldn’t he eat?

“Shinobu looked him over, but she couldn’t find anything wrong, physically.” Aoi continued. “But now that you’re awake, maybe he’ll respond to you?”

Yuichiro nodded. He hoped that would be the case. Another thought came to his mind. “Wait, that other demon slayer, Fujimoto, did he…?”

Aoi looked downcast. “I’m sorry, Yuichiro, but you two were the only survivors.”

Yuichiro felt his stomach drop. A choked sound escaped him, but he recomposed himself quickly. If Muichiro was right, then Hayato had died long before the fight concluded. He couldn’t have saved him. But Hayato should never have tried to fight in the first place. It was just another example of kindness amounting to nothing.

“Can you leave us alone for a bit? I want to talk to my brother.”

“Oh, sure, no problem!” Aoi seemed surprised, but she recovered quickly and moved to leave. As soon as the door shut behind her, Yuichiro turned his head back towards the corner.

“Muichiro, you can come here now. It’s just me.” Yuichiro tried to keep his voice calm and gentle so as to hide his trepidation. His heart leapt in his throat as his twin stood up and walked towards him. His gait was casual, face still utterly expressionless.

Muichiro stopped in front of him and stared, seemingly studying his face. Yuichiro swallowed a sudden lump in his throat. “Muichiro? Are you okay?”

His blank expression didn’t change. Ever so slowly, he lifted an arm and pointed a finger at Yuichiro’s chest.

“…Who…?”

Just one word. Slow, drawn out, like he was struggling to speak. But Yuichiro felt like a bucket of icy water had been dumped on his head. “Huh…?”

“Who… are…” Muichiro trailed off before he could finish. His arm suddenly fell limp, as if he didn’t have the strength to hold it up anymore. He just stood there, blankly staring at, or through, his twin.

Several seconds passed in agonizing silence, until Yuichiro found his voice and words. “Mui… it’s me, Yuichiro. Your twin brother.”

Muichiro’s only response was the slightest shift of his eyes as he refocused on him. But only for a moment as his gaze soon became clouded again. His head tilted forward, bangs shadowing his eyes.

“…Oh.”

He didn’t say anything else. That was it? That was all he had to say to such a revelation? Yuichiro couldn’t believe it. He could feel his heart splitting in two.

What happened to you, Mui?

Tears blurred his vision. He never liked to cry in front of Muichiro, but this time, he couldn't stop it. A part of him hoped Muichiro might react and console him, like he always did when he knew his twin was upset. But he didn’t. Muichiro stood and watched as Yuichiro broke down and cried in the dark, lonely hospital room.

—

Rehabilitation was a blur, a period of time that Yuichiro barely recalled. He trained, ate, and slept, over and over again, for more than four weeks as his body recovered from its injuries. A stab wound to his left abdomen, a minor head injury, burns from an unknown source - he refused to tell Shinobu how he got them -, claw marks on his back, and general overexertion. All these kept him from missions, from distracting himself from reality, so he threw himself into his training. He thought of nothing but becoming stronger.

All the while, his twin tailed him like a silent shadow. He never spoke, and they didn’t spar anymore, but he never left Yuichiro’s side, always watching from the safety of the dark. Even when Tamayo’s blood bags arrived and he was able to eat, nothing changed.

Yuichiro trained on his own. If the other slayers thought Muichiro was creepy before, they found him downright terrifying now. And they avoided him too, more certain than ever he was possessed. Yuichiro didn’t care, of course; Muichiro was all he needed. And yet, he couldn’t even say if Muichiro was really there. He had never felt so alone.

The days blurred together, until one afternoon when Yuichiro was resting at the edge of the engawa, lost in thought. He heard footsteps, and looked up to see Shinobu approach him.

“Yuichiro,” she sat down beside him. “How are you feeling?”

Yuichiro shrugged. “Fine, I guess. It doesn’t hurt.” His heart ached far more than any physical injury.

He noticed that her tsugoku was here as well, a girl who never spoke a word unless ordered to. Kanao, he believed was her name? She walked over to Muichiro, sitting in the shade, and knelt down beside him. She smiled emptily and flipped a coin, but didn’t say anything. Muichiro didn’t acknowledge her, either. Yuichiro couldn’t help but notice how similar they were.

Shinobu hummed. “That’s good. You’ll be able to return to active duty within the week, I suspect.”

“Good.” Demon slaying was just the kind of distraction he needed right now.

Shinobu stared at him. Her ever-present smile slipped, a knowing look in her eyes. “Yuichiro, will you tell me what really happened that night?”

The question shocked the young slayer into full alertness. Why was she asking that now? “I already told you, didn’t I?”

“I want to hear it again.”

Yuichiro dug his nails into his palms, trying to stop himself from shaking. “…We fought against two Lower Moons. I was stabbed and knocked unconscious by Lower Four, but Muichiro protected me. He killed Lower Six but got taken out by a cheap shot, so I had to fight Lower Four on my own. I managed to kill him, but I lost consciousness again. Next thing I knew, I was here.”

He hoped she wouldn’t try to pry further. Unfortunately, she did. “And how did Muichiro kill Lower Moon Six?”

“I don’t know, I was knocked out at the time. He must have used my sword or something.”

“That would make sense, but I don’t think that’s the full story.”

“What are you-”

“Yuichiro, I’m not an idiot. You had acid burns on your skin; that isn’t consistent with either of the demons’ powers as you described them. Furthermore, the wounds on your back were the same size as your own hands. And since I highly doubt you injured yourself, well…”

She didn’t continue, but Yuichiro knew she had him figured out. Really, he was stupid to think she wouldn’t figure it out. He glanced over to his brother, hollow eyes always watching him. If the other Hashira found out what happened…

“Don’t… Don’t tell anyone!” he begged Shinobu, his voice a frightened whisper.

Shinobu blinked, surprised for some reason, but when she spoke, her voice was stern. “I don’t want to, Yuichiro, but if this threatens other members of the-”

“It won’t! He won’t! He…” Yuichiro took a deep breath. There was no choice; he told Shinobu everything. How Muichiro had killed the Lower Moon, how he’d lost control, and how he became the empty shell he was currently. Shinobu listened intently the whole time, not saying a word.

“He’s still a good kid. What happened was a mistake; he’s not a threat to anyone! So-!”

“Yuichiro.”

Shinobu’s voice stunned him into silence. She smiled and put a reassuring hand on his shoulder. “Thank you for telling me.”

“H-Huh?”

“Yuichiro, I’ve known you and Muichiro for months now. You two have shown me that it’s possible for a demon to be good. I trust you, and I trust Muichiro, too. If you say he’s not a threat, then I believe you.”

“Then you won’t tell anyone else, right?!”

“Patient confidentiality, remember? I won’t breathe a word.” she promised. “But I suggest you confide in the Master about this as well. I’m certain he’ll understand.”

“…Yeah, yeah, I’ll do that." He took a deep breath. It would be okay, he assured himself. The Master had placed his faith in Muichiro in the first place; surely he would understand now.

Shinobu giggled and stood up. "Good. Now, I must be going. But, Yuichiro?" He looked up and found her smiling kindly. "Stay strong. I know it's tough now, but you'll make it through this. I'm sure Muichiro will come back to himself one day."

Yuichiro just nodded. He hoped she was right.

"If you ever need someone to talk to, please don't hesitate to find me, okay?"

"...I'll think about it. But thank you," Yuichiro nodded again. Satisfied with his response, Shinobu left to return to her duties inside the estate. Kanao stood up and followed silently behind her.

It took Yuichiro the rest of the week to gather the courage to ask for an audience with the Master, but he needn’t have bothered. Once he was deemed recovered enough to return to demon slaying, a message arrived from the Master himself to speak with him. He headed out as soon as possible, and Muichiro came along too, in a new basket after the original had been destroyed in the last fight.

Soon, the twins were back at the Ubuyashiki Estate, and were led into a dark, lantern-lit room with the Master seated in the middle. Yuichiro knelt down and bowed.

“It’s good to see you again, Master.”

“And you as well, Yuichiro. I am pleased to see your recovery has gone well. Is Muichiro with you?”

Yuichiro nodded, then remembered to add a “Yeah”. The Master’s illness had progressed since their first meeting, his eyesight almost all gone at this point. He opened up the basket lid and a cloud of mist emerged to reform as his brother beside him.

“Now, I called you here to speak about your latest mission. First off, I wish to congratulate you on your defeat of Lower Moons Six and Four. To fight and win against not one, but two Lower Moons is truly impressive.”

Yuichiro frowned. “Thank you, but I didn’t do it alone. Muichiro was the one who killed Lower Moon Six. And there was another slayer there too, Fujimoto… he sacrificed himself to save me from Lower Four’s ambush.”

He felt it was only fair to give the late slayer his due. The Master nodded, smiling sadly. “Yes, Hayato Fujimoto. His death is a tragedy, but I am grateful that he protected you. I grieve for him and the other slayers who lost their lives on that mountain.”

Yuichiro allowed the Master some time to rein in his sadness and recollect himself. “My apologies, let us continue. You say Muichiro killed Lower Moon Six, but you yourself defeated Lower Moon Four, did you not?”

“I did, but…” Yuichiro felt a lump in his throat. He didn’t want to take credit for something he couldn’t have done on his own. “But Muichiro weakened him first, and he distracted him at the last second. If it wasn’t for him, I would’ve died.”

The Master listened to his explanation quietly, looking thoughtful. Then he smirked, a strange expression on someone like him. “Do not sell yourself so short, Yuichiro. Even with help, most slayers would struggle to defeat a Lower Moon. The fact that you did, and at your age, speaks of tremendous talent and skill.”

Yuichiro felt himself blush at the man’s earnest praise. He didn’t think he deserved it, but it made him feel warm and fuzzy all the same. It was annoying. “I… Thank you, Master.”

“I should be the one thanking you, for fighting for our sake. I understand your primary goal is to restore Muichiro’s humanity, but I am grateful nonetheless.”

Yuichiro took a moment to process his words, and then a sudden rush of horror ran through him. The blood! Muichiro had left nothing behind of Lower Six, and he’d lost consciousness right after killing Lower Four. Two Demon Moons, and he’d failed to get the blood of either for Tamayo’s research. Yuichiro’s fists clenched; all that pain and fighting with absolutely nothing to show for it!

“You seem frustrated. Is everything alright?” the Master asked with a frown.

Yuichiro realized he was letting his feelings show and tried to relax. He loosened his clenched hands and jaw before speaking. “I’m fine. Just remembering something, that’s all. It’s not important.”

He wasn’t sure if the Master believed him, but the older man nodded anyway. “Now, I believe we should talk next about what happened with Muichiro.”

Yuichiro’s blood ran cold. He knew?

“Ginko is very fond of Muichiro, so she has chosen to disclose this information to me alone. No one else in the Corps knows the full details of what happened that night.”

Ginko did that? She always did like Muichiro better than him. Probably because he fed her. But right now, he felt grateful to the annoying bird. Still, he hesitated to speak about that part of the night. Talking about it with Shinobu had been hard enough.

“I’m not asking for a confession of guilt, Yuichiro. I have no intention of harming your brother. But I am told he lost control, and we must try to determine why,” the Master assured him. His voice was so calm and honest. Yuichiro felt himself grow more at ease.

He reached over for Muichiro’s hand, assuring himself he was still there. “…I think it happened because he was trying to protect me. I got hurt fighting Lower Moon Four, and I lost consciousness for a bit. When I woke up, Muichiro was fighting the demon, and he was surrounded by this red mist...”

The Master nodded. “Yes, Ginko mentioned that as well. A new Blood Demon Art, perhaps?”

“Yeah, I’m sure of it. That mist burned everything it touched, even me.” His brother’s mist had never hurt him before, but the discoloration of the healing skin on his hands and face were evidence enough. Shinobu assured him it would fade over time; he hoped she was right. “But it’s even worse for demons. It killed Lower Moon Six, and it tore through Lower Moon Four like he was nothing.”

“So Muichiro developed a Blood Demon Art that is capable of killing demons. I do recall that he’d been unwilling to use a nichirin sword in battle, so to evolve in such a way to circumvent that is curious.”

“Yeah, but I don’t think it’s a good thing,” Yuichiro frowned. “That mist was hurting him. He looked like he was sick, and when he got upset the mist attacked everything around him. He said he couldn’t control it, either. And he remembered everything he’d forgotten, like our childhood, but it was just causing him more pain. It was awful to watch.”

“I see…” The Master looked deep in thought. “Do you believe Muichiro might have eaten Lower Moon Six when he killed her?”

“Huh? Well, I can’t really be sure since I was knocked out at the time, but it's possible. That demon had marechi blood, so it would have given him a huge power boost, right? Maybe that’s why he went out of control.”

“Perhaps, but a marechi’s blood is tainted when they become a demon; consuming it would increase a demon’s power, but not as potently. But allow me to propose my own theory. The Twelve Moons possess the most amount of Muzan Kibutsuji’s blood within them. I believe that an influx of Kibutsuji’s blood, absorbed by eating the Lower Moon, would grant an increase in power as well as trigger Muichiro’s suppressed instincts to awaken.”

“So it never happened before because the demons he ate didn’t have enough of Kibustuji's blood, right?”

“I suspect that is the case. Or perhaps his new Blood Demon Art played a part in it. But Ginko said you were able to calm Muichiro down before he could hurt any humans." The Master smiled. "I am thankful for that.”

Yuichiro shook his head. “Don't thank me. I think I messed up, honestly. I put myself in a dangerous situation to force him to act, but it ended up putting too much pressure on him.” He looked at Muichiro, who hadn’t said a word or given any sign he was paying attention to the conversation. “And now he’s like this. He’s been unresponsive before, but this is different. I don’t know what’s wrong with him.”

“Yes, Shinobu has informed me of his condition. It saddens me deeply. But if nothing is wrong physically, the problem must lie within his mind.”

Yuichiro tilted his head. “His mind?” That made sense, but what was he supposed to do about that? He didn’t have the slightest idea where to start.

“Might I suggest writing to Tamayo? She might have better insight into what is affecting Muichiro than we would.”

“Yeah, I’ll try that.” He nodded. “Anyway, I’ve told you everything that happened. What now?”

“Now that you’ve recovered, you can return to active duty. I’m sure a mission will arise for you to take soon. However, there is one more topic I wish to discuss. The position of the ninth Hashira has been empty for a while. And as you know, a demon slayer is able to become a Hashira once they’ve reached the rank of Kinoe and have defeated fifty demons, or one of the Twelve Moons.”

Yuichiro’s eyes widened as he realized what the Master was getting at. “Wait, are you asking me to become a Hashira?!”

“Once you’ve reached the rank of Kinoe, yes. You defeated Lower Moon Four; you are more than worthy of the position.”

“But… but Muichiro helped me! Within him, I’d have died for sure! I’m not…!”

I’m not special. I’m not a chosen one.

“Yuichiro.”

The Master’s calm, firm voice quieted him. “In the span of months, you’ve accomplished what most slayers require years of training to do. You passed Final Selection while protecting another slayer, and you survived a battle with not one, but two Lower Moons. Luck alone would not have gotten you this far; you and your brother both possess amazing talent and skill. Needing help is not a sign that you are weak. We humans can accomplish such greater things when we work together. You can grow even stronger when you fight together. And that is why…”

The Master's unseeing eyes looked directly at him. “I wish for you both to fill the position of Hashira.”

Silence fell. Yuichiro didn’t know what to say. Both of them fill the position of Hashira? “But… Muichiro is a demon. Is he allowed to-”

“Muichiro may not wear our uniform, but rest assured, we do consider him one of our own. And nothing says that a Hashira must be human, either.”

Yuichiro still didn’t know how to respond. His mind screamed in protest, that he wasn’t worthy of such an honor, but how could he say that in the face of all the confidence the Master had in his abilities? He could see, now, why the other Hashira revered him so highly. He too felt like he could go to the ends of the earth for this man who believed in him so unconditionally.

“T-Thank you… It would be an honor.” He finally decided, bowing his head.

The Master’s smile grew. “Thank you, my child. Ah, but we shouldn’t get ahead of ourselves. You still have to obtain the rank of Kinoe, so do your best in the battles ahead.”

Yuichiro nodded. “I will.”

“Good. And, it would please me greatly if Muichiro could find himself again by that time.”

Yuichiro looked at his brother again. He wanted that too, more than anyone. “I’ll find something, some way to bring Muichiro back. Count on it.”

—

Yuichiro and Muichiro stayed at the Ubuyashiki Estate that night. It had been a long time since they’d slept in their room here; the older twin hoped it might get a reaction from the younger. But no such luck. Muichiro remained as listless as ever.

“Come on, Muichiro. Let’s go to bed.” Yuichiro took his hand and pulled him towards their futon. Muichiro followed along, mimicking his motions as Yuichiro laid down to sleep. He settled down beside him, letting the older twin clasp their hands together. Yuichiro found that he couldn’t sleep without his brother by his side anymore. If he tried, he’d be too scared, for fear that Muichiro wouldn’t be there when he woke up.

Muichiro closed his eyes. It was never clear if he actually slept at night; his breathing was always slow and deep. After a few minutes of staring awkwardly at his face, trying to decide if he was asleep or not, Yuichiro spoke up, his voice soft.

“Muichiro, can you hear me?” He hoped he could. Not this hollow puppet, but the real Muichiro. The younger twin opened his eyes half way, hazy irises illuminating his face.

“What did you think of today? It was a wild ride, wasn’t it?” he asked, as if he were just having a normal conversation. “I was scared when Shinobu found out the truth, but she ended up being really understanding. And she said she believes in us. She believes in you.”

Muichiro stared at him, not blinking, not responding.

“And not only that, but the Master wants to make us Hashira! Can you believe that? He wants both of us to share the role! I know you were always worried about being a real demon slayer, but this is proof that you are one. You see? You… you never had anything to worry about…”

He was rambling, and he might as well have been talking to a wall. This wasn’t the first time he’d tried this, anyway. Every night he talked and talked until he fell asleep, hoping for some kind of answer. It never happened.

So this time he tried something different. He didn’t know why; maybe it was because that night was at the forefront of his mind thanks to Shinobu and the Master. That night, he had failed his brother; he couldn’t fail him again.

“Muichiro, you are not nothing. You never were. I’m sorry I said that you were. You are a demon slayer, and you can save people. And I’m so proud of how strong you’ve become, and I want to tell you that! But you have to wake up first. You have to come back…!”

His words were met with silence. The glow in Muichiro’s eyes flickered like a dying candle, but Yuichiro wasn’t delusional enough to think that meant anything. Fighting back tears, he pulled his brother’s hand towards his chest and held on tight.

“...Just go to bed, Mui. We’ll need our strength for tomorrow.”

Muichiro’s only response was to close his eyes, but at least that meant he was listening. Yuichiro followed suit and allowed himself to drift off into sleep. Ever since that night, Yuichiro didn’t dream. Not like before, at least. His sleeping mind spent the nights wandering an endless white mist.

Perhaps it was just his imagination, but this time, the mist felt a little heavier, a little sadder.

Chapter Text

“I’ll find something, some way to bring Muichiro back. Count on it.”

That’s what he had promised the Master, but…

It had been two months since that promise. Two months since the Master asked for both twins to take the role of Hashira. Two months, and Muichiro was still lost inside himself.

“Mist Breathing…”

The demon let out a shout, it’s Blood Demon Art taking the form of explosive orbs of light like firecrackers. Such an unsubtle ability; no wonder it only hunted during festivals. But Yuichiro had driven it into an abandoned building far from the celebration; he had it cornered now.

“Fourth Form, Shifting Flow Slash!”

Cutting the crackling orbs would set them off early, so he simply used his fourth form to crouch low and slide under them. He shot forward and slashed, only managing to take the demon’s leg off as it jumped. Unsubtle though its powers were, it was still quick on its feet. But the demon was knocked off balance and fell on top of some old barrels. They broke apart under its weight, kicking up a cloud of dust and debris that shielded the demon from view. Yuichiro growled and jumped towards it, anger fueling his swing.

A burst of light went off right in his face. He stumbled, blinded, and fell to his knee. The demon was no longer in front of him. He sensed movement behind him, and heard it cry out.

“You’re finished!”

In any other situation, Yuichiro wouldn’t be worried. In any other situation, he knew Muichiro would jump in to protect him. Muichiro always had his back. But the basket he wore remained inert, weightless with only mist inside.

Yuichiro didn’t need help. Most demons he could kill on his own. Even this one was hardly a threat for a slayer of his level. But as the demon attacked from behind, claws pointed at his throat, he couldn’t bring himself to get out of the way. Muichiro always had his back. Always. So what if…

What if…

A slashing sound, and the demon let out a gurgling shriek. Yuichiro spun around with eyes blown wide and saw its head tumble to the floor. He looked up, daring to feel a glimmer of hope.

The sight of a black and white haori strangled that hope. A pair of mismatched eyes, gold and teal, looked down, narrowed in disapproval.

“Sloppy. Your forms were all off. And I know you could have dodged that, but you didn’t even try.” The Serpent Hashira reprimanded him. “Were you trying to die?”

Yuichiro glared and turned away. Muichiro’s basket remained damningly still. “…What do you care?”

“Hmph,” Obanai snorted. “Because you’re young, and you killed a Lower Moon. You have potential to become a Hashira, and I’d hate to see you die pointlessly to a weak demon like this.”

“If the demon was so weak, then why are you even here?” Yuichiro stood back up. “Don’t tell me you were just in the area. You were clearly following me.”

“…Yes, I was.”

“Why?”

“Because Kanroji is worried about you.” Obanai answered bluntly. “And so is Rengoku, and Kocho, and the Master and his family. You have a lot of people who care about you, whether you can see that or not.”

“You’re one to talk,” Yuichiro muttered under his breath.

“What was that?” Obanai asked with a dangerous undertone. His snake let out a hiss.

“Nothing. And I don’t need your concern, either. I can handle…”

He stopped as he noticed mist drifting across the ground. Like the snake wrapped around Obanai’s neck, it poured from the basket and slithered towards the demon’s disintegrating corpse. Yuichiro and Obanai both watched silently as the mist swallowed the body up, then returned to the basket just as quietly.

Obanai looked towards Yuichiro, who had bowed his head to hide the tears of frustration building in his eyes. The Serpent Hashira’s expression softened.

“Did you think he would save you if you put yourself in danger?” Even his voice was soft.

“…” Yuichiro didn’t answer; he didn’t trust himself not to cry if he did. He wiped his eyes with his haori’s sleeve.

Obanai continued, the harsh edge returning to his tone. “Maybe he would have. Or maybe, you would have just died. And then what? You’d leave him all alone, for however long a demon like that might live? You might as well take his head off now and spare him the suffering.”

Yuichiro tensed up. “You-!” But just as quickly, his anger melted away, replaced with shame. Obanai was right. What was he thinking?

“You get it now, don’t you? Your brother needs you. So don’t go throwing your life away.”

“…I won’t.” Yuichiro resolved. He couldn’t forgive himself if he died and left Muichiro alone.

“Good.” Obanai nodded and looked out the window. The din of the festival could be heard in the distance. The Hashira seemed to be considering something, but his face was unreadable. “…Good luck. Perhaps you should stick around, enjoy the festival. Be a kid while you still can.”

Then he was gone, out the window and leaping across the rooftops until he disappeared into the night. Yuichiro was left alone. He adjusted the basket’s straps on his shoulders, reassuring himself his twin was still there. New tears formed now that no one was around to see them.

“I’m sorry, Muichiro… I’ll do better… I’ll be stronger for us both… I promise.”

—

Another week passed, and Yuichiro still couldn’t see a way forward. He felt like he’d tried everything to bring Muichiro back. Nothing worked. He had obtained the rank of Kinoe weeks ago, but he couldn’t accept the Master’s offer. He couldn’t become a Hashira, not while Muichiro was still a hollow shell of himself.

No one had answers that could help. Even asking Tamayo hadn’t yielded much more than vague theories on what was going on inside him, physically and mentally.

Yuichiro,

I must thank you for your aid in advancing my research. Muichiro is truly an oddity amongst demons; the cells in his blood behave unlike those of any I’ve observed so far. They actively resist and destroy the cells of other demons, including Kibutsuji and even my own. Given the anti-demon properties of his Blood Demon Arts, I believe this means Muichiro’s body is evolving specifically to become more effective at destroying demons. How or why is unclear, but I will inform you if I learn anything more.

As for the reason you’ve reached out to me: my ability to make an assessment of Muichiro's condition is limited without being able to visit in person, but I can give my thoughts based on what you’ve told me. My theory is that Muichiro’s reduced mental and emotional capacity was a way to suppress his natural hunger and demonic instincts, and this recent behavior is an extreme form of that to cope with losing control. While it is possible it will wear off with time, I believe it is more likely Muichiro will resist any attempts to awaken him unless a breakthrough is made. Unfortunately, I cannot tell you what may trigger this breakthrough. It may be one thing, or a combination of factors. I wish I could be of more help, but demon psychology is little understood even by myself.

I wish you the best of luck, and I will reach out should I find anything that may be of use to you.

Tamayo

Yuichiro had crumpled up the paper and tossed it away, not even bothering with writing a response.

At the moment, the twins were back at the Butterfly Estate. Obanai’s words had spurred Yuichiro into finally taking up Shinobu’s offer. He felt bad for ignoring her for so long, but he had his missions and she was a doctor and a Hashira. They were both busy.

“Thank you for taking the time to see me,” he said again. “I know you probably have more important things to do.”

“Not at all! I told you, after these past few days, I appreciate the distraction!” Shinobu laughed.

The two of them, along with Muichiro and Kanao, sat in the shade of the engawa, various sheets of colored paper laid out around them. They’d been talking casually and drinking tea for almost an hour before Yuichiro brought out the sheets of origami. The older twin finished folding a green paper crane, then set it down in front of his brother next to a pair of purple and orange cranes.

“Do you want to try now?” he asked even though he didn’t expect an answer. Muichiro loved origami, but this wasn’t the first time he’d tried this. He didn’t think it would jog his memory, but the act of paper folding was soothing, and sometimes his twin would actually participate. Those moments gave him hope.

Ever so slowly, Muichiro grabbed a pink piece of paper from the top of the pile. Yuichiro and Shinobu watched with bated breath as the young demon methodically folded the paper the way he’d just been taught. His claws carelessly scratched the paper, but he kept folding anyway. When he was finished, Muichiro held out a slightly torn crane, his expression blank.

“You did it!” Yuichiro cheered. He eagerly took the battered little crane and set it down with the others. Looking at the four cranes, he idly wondered if he could fold a thousand of them and wish Muichiro back to normal. But that was just a stupid fairy tale.

“I’m impressed!” Shinobu exclaimed. “Has he done this before?”

Yuichiro nodded. “Sometimes, yeah. He seems to have days that are better or worse than others.”

“I see. Has anyone tried talking to him besides you recently?”

“Uh huh. About a month ago, Kyojuro came by before he had to leave on another long mission, and Mitsuri dropped by a couple weeks ago. They talked a lot, and Mitsuri gave him this cat charm, but it didn’t do much.” He paused, thinking. “Actually, I think Iguro was there too when Mitsuri visited. Maybe that’s why he followed me on my last mission.”

“Perhaps. I know Iguro seems unfriendly, and to some extent he is, but he’s always had a soft spot for children.”

“I’m not a child,” Yuichiro huffed. He was a demon slayer, damn it; he was even in the running to become a Hashira. Children did not become Hashira.

“Of course not,” Shinobu said in a humoring tone of voice. Yuichiro turned away with a pout, so she giggled and turned to the other twin. “Muichiro, sweetie, are you having fun?”

Muichiro looked up at her and tilted his head. He really did seem more responsive today. Some days, he was so lost in his own head that he didn’t notice people right in front of him.

Yuichiro shivered. It was cold; a light snow had fallen just an hour ago. He reached for the tea cup next to him and found it chilled. “Mui, wait here. I’m gonna get some more tea. Do you want some too, Shinobu?”

The Insect Hashira shook her head. “Thank you, but there’s no need. I should be returning to work, anyway.” She stood up. “I’ll walk with you. Kanao, will you stay here with Muichiro?”

Kanao nodded. Her smile didn’t change, so it was impossible to tell what she was thinking, but she seemed content to watch Muichiro as he reached for another sheet of paper.

Yuichiro and Shinobu headed back inside the manor. Shinobu leaned in close and whispered as they walked.

“How are you holding up?” she asked once out of earshot.

Yuichiro sighed. “...I don’t know. I’m just tired. Do you ever worry about Kanao like this?”

From what he knew of the girl, she was always silent and expressionless, whether amongst strangers or with her closest friends and family. She needed that coin just to make her own decisions. She wasn’t a demon, but she and the current Muichiro were very much alike in their apathy towards everything.

Shinobu smiled, understanding. “Kanao just needs to find the right person to help her come out of her shell. It may take time, but I believe that it will happen one day. That’s just how humans are; they need other people to help them grow.”

Yuichiro frowned. “But what about Muichiro?”

“I believe he is the same. But the difference is Muichiro already has his right person here with him.” She gave him a sly glance. “If anyone can bring him back, it'll be you, Yuichiro.”

Shinobu had such faith in him; Yuichiro wished it was better placed. But he didn’t want to worry her further, so he did his best to smile. “Yeah, I know. Thanks, Shinobu.”

“No need for thanks. Oh, but I forgot to mention…!” She clapped her hands together. “Shinazugawa is staying here for a few days for recovery. I know you two don’t get along, but try not to cause any trouble, alright?”

Yuichiro’s mood soured immediately. Ugh, that guy… Still, he agreed. “I’ll do my best.”

As long as he doesn’t start anything…

He and Shinobu split up after that, and Yuichiro made his way towards the kitchen. Maybe he could grab some snacks while he was there. If only Muichiro could eat human food; he’d love to try jogging his memory with some furofuki daikon.

As Yuichiro entered the kitchen, he expected to see the Butterfly girls or Aoi preparing lunch, so he couldn’t help but stop and stare at the sight of a familiar white-haired man shuffling about.

Oh, you’ve got to be kidding me…!

“What are you doing here?”

The man turned around at his voice, and it was indeed the Wind Hashira, the unpleasant expression on his face as ever present as his scars. His face somehow turned even more sour at the sight of Yuichiro. “Ugh, it’s you.”

“Yeah, it’s me. What are you doing here?”

“What does it look like? I’m cooking.” Indeed, there was something simmering in a pot on the stove. Whatever it was, it smelled good.

“Why?”

Sanemi scoffed and held up his left arm. His wrist was in a cast. “I sprained my wrist in my last mission and Kocho won’t let me fight until it heals. Now I’m hungry and I didn’t want to wait until lunch. What’s it to you?”

“I didn’t know you could cook.” Yuichiro was quite surprised; he didn’t think there was room for anything but fighting in his brain.

“Tch, do you always assume things about people you don’t know?” Sanemi rolled his eyes. “For your information, I was the oldest in my family, so cooking was something I needed to learn.”

“You’re an older brother?” Yuichiro was shocked and horrified that they had anything in common.

“…Not anymore.” Sanemi muttered after a long pause and turned back to his cooking. Knowing better than to pry further, Yuichiro instead walked over and stood on his toes to look into the pot. Some kind of broth was simmering inside.

“…Hey, can you make furofuki daikon?”

“Duh, who can’t?”

You’d be surprised, he thought, remembering the one time when Muichiro had tried to help their mother prepare it. One time, because after that they’d needed a new pot and Muichiro was banned from anything involving fire. “Can you make some now?”

“I’m making food for me, brat, not you.”

“Fine, then I’ll just use it after you.” Yuichiro scowled and crossed his arms. He leaned against the wall and glared at Sanemi, who stared awkwardly back.

“…Are you just going to stand there the entire time?” He finally asked.

Yuichiro shrugged. “I don’t have anything better to do.”

“You could go hang out with your brother instead of bothering me.”

“I was, but…” He stopped. Should he really be talking about this to Shinazugawa, of all people? But he was too tired to care anymore. “It hurts to see him like this. Sometimes I want to get away for a bit.”

Sanemi paused in his stirring the broth. “What happened to him? He’s always been creepy, but at least he acted like a kid sometimes. Now it’s like looking at a ghost.”

Yuichiro bit back a retort, because of course the Wind Hashira was right. Anyone would have noticed the change in his brother. “Master Kagaya says he’s lost in his own mind. I’ve been trying to find a way to bring him back, but nothing works. I’ve tried all his favorite things, spent nights talking to him about our childhood, but nothing’s changed. Half the time he doesn’t even acknowledge me. I don’t know what to do anymore.”

Yuichiro felt utterly hollow; he was too tired to even cry anymore. Sanemi returned to his cooking, but slower, as if he was thinking about what Yuichiro told him. “Well, I don’t have any demon siblings, so I can’t tell you what’s wrong or how to fix it.”

Yuichiro hung his head. Of course he wouldn’t have an answer. Who would? Nothing like this had ever happened before. “I wish this had never happened. I wish we could just go home and-”

“Then go home.”

“Huh?”

“Look, you’re an annoying brat. But brats like you shouldn’t be demon slayers; they should just be kids. You want to get your brother back, right? Then you should go to the place where he was able to be a kid.”

Yuichiro blinked, utterly stunned. Go home. To the place where all their memories rested, the good and the bad. It seemed so obvious coming from Sanemi’s mouth. Why hadn’t he thought of it himself? “That’s… Do you really think that could work?”

Sanemi shrugged. “Well, obviously I can’t say for sure, but who knows? It might trigger something.”

All thoughts of tea and snacks chased from his mind, Yuichiro immediately turned and headed back the way he had come. Sanemi scowled and returned to stirring his boiling broth in peace. “Dumb kid…”

Yuichiro marched back out, his thoughts whirling. Home was a few days away at the least. He’d have to reach out to the Master, request time off from missions, and pack for the trip. He stepped onto the engawa and froze. Muichiro and Kanao sat where he’d left them, surrounded by no less than a dozen paper cranes, and yet another being folded in his twin’s hands. He watched as Muichiro finished and set it down, then reached for another paper, only to stop, confused, at the realization there were none left. Had he been mindlessly folding cranes this whole time?

Kanao seemed enraptured by his folding of the origami birds. As Muichiro patted the floor in confusion, her lips quirked up, and a soft sound escaped her.

…Did she just giggle? Yuichiro shook off his surprise and approached.

Muichiro looked up. His face was still blank, with no indication that anything had changed inside him. But Yuichiro hoped that he could finally fix that. He knelt down in front of his brother and took his clawed hand in his own.

“Come on, Mui. We’re going home.”

—

Home looked exactly how they had left it.

More than seven months they’d been gone, and aside from the layers of snow covering everything, it hadn’t changed a bit. A painful reminder of the past persisting into the present.

Yuichiro stared at the house. He wanted to go inside - it was cold, after all - but his legs wouldn’t move. Now he knew why he hadn’t thought to come here. He hadn’t thought about this place at all since they left. He had refused to think about it, wanting to push all those painful memories away. But right now, those memories were his only chance of getting his brother back.

Now if only he could make himself go inside.

“Calm… down.”

“Huh?”

Muichiro stared at him blankly. The sky was overcast, so he could safely walk about even though it was daytime. But moreover, had Muichiro just talked? Yuichiro hadn’t heard his twin’s voice since the day he first woke up in the Butterfly Estate.

Slowly, the younger twin raised a claw and pointed at his older brother’s heart. “Calm… down. Just… a house.”

Then Muichiro walked past him, disappearing inside. Yuichiro was still frozen in place, stunned by the fact that Muichiro had talked for the first time in months. He looked back at their former home, and swallowed the lump in his throat.

He’s right, it’s just a house. Pull yourself together, Yuichiro.

Finally, he was able to move his legs and follow Muichiro inside. The interior was very dark, the lack of sunlight from outside only making it harder to see. As his eyes adjusted, they strayed over the bloodied futons, the scratched walls. Aside from the snow that had blown in, it really did look the same as they’d left it.

“Do you remember this place, Muichiro?” he asked softly, as if speaking too loud might cause the whole house to come crashing down.

Muichiro tilted his head towards him, glowing eyes more eerie than ever in this place of memories. “…No. Why…?”

Yuichiro sighed. “This is our old home. We lived here for eleven years, along with Mother and Father. They died when we were ten; their graves are down the path behind the house.”

Muichiro didn’t respond, but Yuichiro noticed the glow in his eyes flicker ever so brighter. It was subtle, but he had to believe that being in this house was having an effect on him.

The older twin knelt down to inspect the long unused hearth. He figured he could get a fire going with enough dry wood. “I’m gonna get started on dinner. You can walk around or do whatever, but don’t go too far, okay?”

Muichiro said nothing as he turned and walked back outside. Yuichiro sighed again; he could only hope that his brother would listen to him. He stood and went outside as well, aiming to grab some wood from beside the house, when he saw his twin’s kimono vanish around the corner. Curiosity got the better of him and he decided to follow at a distance.

The crunch of snow and Muichiro’s demon hearing likely made his presence obvious, but if Muichiro was aware of his tailing, he didn’t show it. His twin walked languidly around the perimeter of the house, showing little interest in anything. The path on the ground was long buried by snow, but he stopped behind the house and turned his head towards the forest. He lingered a moment longer before heading in that direction.

The same direction as Mother and Father’s graves.

Yuichiro was quick to keep up; even if he knew the way by heart, he didn’t want to lose sight of his brother. Minutes of silence but for the crunching of snow beneath their feet followed, until those familiar stones came into view. Muichiro stopped in front of them, staring straight down. Yuichiro couldn’t see his face from this angle.

Slowly, he walked up and stood beside his brother before the two graves. He gazed somberly at the stones; were Mother and Father watching them now? Would they be disappointed at how badly he’d failed to protect Muichiro? He took a deep breath and tried to smile.

“Mother, Father… It’s been a while, hasn’t it?” He fidgeted with his fingers as he spoke. “Sorry we took so long to come and visit. Things have been really eventful, lately.”

Truthfully, if it wasn’t for said events, he doubted he would have ever come back here at all. Yuichiro wondered if their parents would be disappointed in him for that, too.

“Muichiro and I are working as demon slayers now. It’s dangerous, but we’ve killed a lot of demons, and saved a lot of people. And a lot of the Corps doubted us at first, doubted that a demon could protect humans, but Muichiro’s proved them all wrong. He’s amazing.”

At some point, his words and his gaze had shifted from the graves to his twin. Muichiro seemed expressionless, but when Yuichiro looked closer, he could see his eyes twitching, his hands shaking. He bowed his head, long hair shadowing his face.

“…Stop it…”

Even his voice was trembling. Yuichiro reached out hesitantly, worried he might startle him, but the instinct to comfort won out. He grasped Muichiro’s hand and squeezed. “Muichiro, listen to me. Whatever’s going on, we can get through it together. But you need to stop hiding inside yourself. You need to come back.”

“I said… stop it,” Muichiro insisted. Tears fell and splashed on the stones. “I can’t...”

“Why not?” Yuichiro pleaded for an answer.

Muichiro refused to give him one. He only flexed his claws, long and sharp, again and again. His gaze wouldn’t leave them. But to Yuichiro, that simple action confirmed what he always suspected.

“…Muichiro,” His brother lifted his head and turned towards him. “Look, what happened on the mountain was scary. Terrifying, even. But as terrified as I was, I was more terrified for you. I was scared you’d lose yourself. But closing yourself off isn’t the answer. Humans can’t live all on their own, separated from everything.”

“I’m not… human.”

“That doesn’t matter. Even if you’re a demon now, you’re still human at heart. You’re still my brother. And as your brother, I’ll do everything I can to help you. I’ll always be right here by your side. And I’m sure Mother and Father feel the same way, wherever they are. So… there’s no reason for you to shut yourself away anymore…!”

“But-”

“Please, Mui!” Yuichiro interrupted, gripping his hand tighter. “I can't do this on my own! I need you back!”

They were both crying now, that much was obvious. It was getting harder to see, white covering the area, and while at first Yuichiro thought it was falling snow, he soon realized it was mist. Mist that was rising up around them both.

“I can’t… If I do… I’ll hurt you.” Muichiro choked out. “I’m not…”

His body dispersed, his hand in Yuichiro’s vanishing as the cloud of mist surged back towards the house.

“Wait, Mui!” Yuichiro called, but he was already gone. Left all alone, he couldn’t stop himself from letting out a scream of frustration. “Damn it! That stupid, stubborn-!”

His eyes fell on the lonely, snow-covered graves, and his anger melted away. Yuichiro knelt down and started to brush away the snow, cleaning up the long-neglected burial site.

“…Yeah, I know. He’s scared. If our situations were reversed, I’d be scared too. I just don’t know what I can do to help. I’m a failure of an older brother…”

When Yuichiro finished and returned to the house, he found Muichiro curled up in a bundle beneath their mother’s old futon. Disheartened, he set to work on lighting the hearth so he wouldn’t freeze to death. With no appetite for dinner as night fell, Yuichiro simply laid down to sleep.

But even sleep wasn’t kind enough to grace him. He stared across the room at the lump beneath the futon, scared it would disappear if he looked away. Finally, he groaned and got up. He walked over and lifted up the mat, finding hollow eyes staring back.

“…Can I join you?”

Muichiro silently shifted over to make room for him. Yuichiro crawled under and settled beside him, taking comfort in the warmth of his body next to his. Finally, he felt secure enough to drift off, hoping against hope that tomorrow would be better.

—

Yuichiro was shocked into awakeness by yet another dream of red mist and turquoise eyes.

Habit drove him to look for his brother, but Muichiro was still curled up beside him, the slow rise and fall of his chest showing he was alive. It put him at ease, but he knew he wouldn’t be able to get back to sleep.

Yuichiro decided to get up, trying not to wake Muichiro, but his twin didn’t even stir. Once free, he grabbed his sword and hung it on his belt. Maybe some training would help, and he needed the fresh air. Making his way to the door, he cast one glance back at his brother before stepping outside.

Though the sky was still dark, it was almost morning; the sun would rise in less than an hour. The layer of thick clouds had also parted to reveal the moon overhead. The winter chill bit at Yuichiro's face, but he ignored it as he walked away from the house to find a good training spot. He didn’t get far, however, before something caught his attention. Sticking out of the snow were logs and tools scattered in a very deliberate formation. It only took him a second to remember that this was the spot where Muichiro had fought the demon that attacked them that fateful night.

It was also the spot where he’d been turned by-

“I did not expect… to find you here.”

Yuichiro froze, and not from the cold. He forced himself to look up and up, at a towering figure that had not been there a second ago. A man dressed in a purple kimono, wild black hair blowing in the wind, and a sword at his side. But all those were footnotes to the six glowing yellow eyes that held him captive, staring into his very soul. A pair of kanji decorated his middle set of eyes.

Upper One.

Chapter Text

Upper One.

This was Upper Moon One.

Yuichiro’s hand flew to his sword, but he couldn’t pull it from its sheath; his arm was shaking too much to even try. The presence of this demon was overwhelming. He was majestic and terrifying, like the eye of a fierce storm. None of the demons he had faced before compared to the being standing before him. Even Lower Moons Six and Four were nothing before this man, the strongest of the twelve Demon Moons.

Had Muichiro really met this demon? Back when he was eleven, untrained with a sword, and barely even aware of what a demon was? Yuichiro couldn’t imagine how terrified he must have felt; he was barely holding it together himself.

It was the Upper Moon who spoke first in the face of Yuichiro’s silence. “Why… have you returned here?”

Yuichiro’s eyes narrowed. What kind of question was that? The shaking in his arms lessened as anger gave him courage, enough to pull his sword free of its sheath and hold it between himself and the demon.

“This…This is our home! What’s your excuse?”

He probably shouldn’t be trying to antagonize the second strongest demon in the whole world, but it was the only way he could maintain some level of bravado in the face of the overwhelming presence standing before him.

Upper Moon One’s eyes narrowed, and Yuichiro struggled to keep a brave face. “I followed the scent… of my student.”

Student? Then Yuichiro remembered, Muichiro had met the Upper Moon and trained with him while he’d been fighting in the Final Selection. His blood boiled and fury marred his face. “You’re the one who turned Muichiro!”

“I am,” the demon nodded. His tone was flat and he didn’t elaborate; Yuichiro couldn’t tell what he was thinking or feeling.

Nevertheless, that casual tone pissed him off. “That’s it? That’s all you have to say?”

“What else is there… to say?”

“Oh, I don’t know!” Yuichiro couldn’t help the bitter sarcasm edging into his voice. “How about why you turned him into a demon? Why you ruined our lives? Maybe you could explain that?!”

His sardonic tone didn’t seem to bother the Upper Moon, who looked deep in thought. “I found him on the brink of death… after defeating a demon. Driven only by rage… without even a nichirin sword… I sensed an immense potential. It would have been a waste to let him die… so I allowed him to become a demon.”

The Upper Moon’s words only made Yuichiro angier. Allowed him… like it was some honor to be turned into a human-eating monster? To never be able to walk in the sun? “Did you ever think if that's what he wanted?”

“If I had not… then he would be dead.”

The Upper One spoke with such certainty. Yuichiro’s fury fled him, replaced with a cold dread. What if Muichiro had a choice? Would it have been better for him to have died as a human than be forced to live as a demon? Yuichiro already knew his own answer. He was an older brother, and moreover, he was selfish. He would have wanted Muichiro to live, no matter what. But theorizing what ifs was useless. In the end, this demon made the choice for him.

“I was not wrong… in my decision.” The Upper Moon said, as if he could read his thoughts. “He has a prodigious talent… that I have not seen since the Sengoku Era. Talent like that… must be cultivated.”

The Sengoku Era? But that was over four hundred years ago! This demon was that old? But Yuichiro’s surprise was brief. “You keep talking about his talent and potential, but you haven’t said anything about why you want it. Why are you training him? Why do you want him to be stronger? Is it because of our bloodline?”

The Upper Moon was silent for a long time. Slowly, Yuichiro realized he was more right than he thought. “Seriously? What does a demon want with our bloodline?!”

“You two… are descendants of the family… that birthed the first users of Breathing. That family… was known by the name of Tsugikuni.”

Tsugikuni? It was the first he’d heard of that name. “Well, I don’t know how to tell you this, but I’ve never heard that name before. Our family name is Tokito.”

“Indeed, the Tsugikuni name has died out. It was inevitable… after hundreds of years. But the Tsugikuni blood persists in you both.”

“Don’t give me that bullshit! If it’s really been hundreds of years, then not a drop of that blood remains in us!” Yuichiro snapped. “We were just woodcutters! We don’t know anything about the First Breathing!”

“Perhaps not… but the fact remains… that you have survived this long.” The Upper Moon took a step forward, and Yuichiro backed up with his sword drawn.

“I...I don’t know what you’re planning, but I won’t let you get anywhere near Muichiro!”

“Hmph.” The demon’s hand hovered near his sword’s hilt. “I do not think… you have the power to stop me.”

Yuichiro grimaced. He knew full well that the Upper Moon was right. If this came to a fight, then he was dead. No question.

But the Upper Moon relaxed, his hand falling to rest at his side. “However… I am not here… to take him away from you.”

“Huh? Then why are you here?” he asked, baffled.

“The night that you were attacked… I knew you were still alive. But I admit… I did not believe you had the same potential… so I left you to die. To be eaten… by your brother. And yet, you survived… and grew strong.”

“Are you trying to compliment me?” Yuichiro growled. “If you are, you can take that praise and shove it up your-”

“Do not interrupt me, boy,” the Upper Moon growled suddenly. The weight of his presence doubled; Yuichiro choked on his words. The demon drew in a breath, and his voice was calm again when he continued. “I can see now… that I made a mistake… all those nights ago.”

“You… You did?” Yuichiro couldn’t help the sudden trepidation that filled his whole body. He didn’t like the way the Upper Moon was looking at him with new interest.

“Yes. My mistake… was not turning you both.”

He didn’t have time to think about the implications before the Upper Moon was right in front of him. He hadn’t even seen him move, nor did he see the outstretched hand that suddenly gripped him by the neck. Yuichiro gasped for air as the Upper Moon raised his other clawed hand. His sword slipped from his grasp and sank into the snow.

“Do not fear… When you become a demon… you will be able to stay with your brother. I am certain… that you will both be of use to my lord.”

Yuichiro couldn’t breathe; anger and panic mixed together inside him. He didn’t want to be a demon. He had seen how Muichiro suffered, how much it hurt him to fight against his demonic nature. To make him human again was the sole reason they had come this far. He couldn’t let himself become a monster; he had to stay human, for Muichiro’s sake!

He fought with all his strength against the Upper Moon, but his grip was like an iron vice, unmoving and unbreakable. Spots filled his vision as he was further deprived of air.

“Do not struggle… the transformation will be less painful… if you do not resist.” The demon dug his claws into his palm, drawing blood, but then he paused, his eyes shifting to the right. Suddenly, he released Yuichiro and stepped back just as something white cut through the air in between them.

Yuichiro stumbled back and fell to his knees, hand flying to his aching throat. Then he looked up, and his eyes widened at the sight of Muichiro standing in front of him, mist sword wavering as his empty eyes glared at the Upper Moon.

“Don’t… touch… him.”

His voice was flat, but his body was tense, agitated. Upper Moon One looked surprised for a moment before his eyes narrowed.

“Hm? You have… sealed yourself away. Why?”

Muichiro didn’t answer; he only imposed himself between his brother and the demon, sword raised and ready to strike. The older demon did not seem to appreciate the lack of response.

“Answer your teacher… when he speaks to you.” Upper Moon One’s sword left its sheath faster than Yuichiro could blink, and Muichiro bit back a scream as the slash cut a diagonal gash across his body from hip to shoulder. Crimson blood splattered across the pure white snow.

“Muichi-” his cry was cut off as Muichiro suddenly grabbed his uniform collar and tossed him several feet away. Before Yuichiro could get back up, a blood red mist flooded the area, forming a barrier that cut off his view of Muichiro and the Upper Moon. The fog rumbled, thick and angry, and Yuichiro knew right away he would not be able to walk through it unscathed.

“Muichiro!” The older twin shouted at the mist, but it was no use. There was nothing he could do to help his brother now.

—

Protect him.

That one thought surfaced above the sea of mist inside his head. Muichiro clung to it as the mist threatened to pull him under again. He could sense the demon’s immense power. He knew he was in danger.

The Upper Moon looked around at the blood mist surrounding them. “…Your power has grown greatly. Rage has driven your Blood Demon Art… to take a new form. A deadlier form. That rage… is the root of your power.” He looked genuinely curious, even impressed. Muichiro didn’t know what he was talking about. The older demon’s eyes settled back on him, and narrowed in displeasure.

“And yet… you lock yourself away… you suppress that rage. Tell me… What are you hoping to accomplish?”

Upper Moon One swung his sword again, slicing off Muichiro’s right hand. His only reaction was a hiss. The fog in his head thinned for a moment, fiery heat spreading through his veins, before it thickened twicefold. The fire went out, drowned beneath the sea of clouds.

Don’t get angry.

“Your reflexes… and your regeneration… are slow. What have you been doing… all this time?”

Muichiro didn’t answer. Red mist poured from the stump of his hand, formed into the shape of a sharp-fanged beast, and surged towards the Upper Moon.

“Moon Breathing, Sixth Form: Perpetual Night, Lonely Moon - Incessant.”

Multiple slashes blew away the mist, smaller crescents expanding from the main cuts. The crescents ripped through the surrounding trees and Muichiro’s body, positioned to make sure he was between the attack and the human just outside the barrier of mist. His eyes never left the Upper Moon; the fog thinned as something pierced through. A moonlit night, the bitter smell of wisteria in the distance. This very same demon, performing movements of unmatched skill and beauty for his eyes only.

Teach…er…?

Upper Moon One’s sword stabbed through his abdomen, drawing a scream. Dimly, he heard the boy shouting beyond the red mist. The fog in his head flooded in, trying to drown out the pain.

Don’t lose control.

“You fear yourself. You fear your potential. You limit your power… for fear you cannot control it. Who can you hope to protect… with such weak-hearted resolve?”

Muichiro shook his head. He felt the cracks forming along his face, and fought to keep them from opening.

Don’t lose control!

His body exploded into white mist, freeing him from the demon’s sword. The red haze around them immediately began to die down, losing substance as it grew weaker.

“So you cannot sustain… both Blood Demon Arts at once…” the Upper Moon observed. The mist surrounded him on all sides, obscuring his vision. At the edge of the fog, Muichiro spotted the white-tinted sword lying in the snow. He hesitated, the blade stirring something in him, but the feeling soon vanished. He snatched it up and swung at the Moon’s exposed left side, but Upper One simply turned and slashed upward, catching the blade as it cut towards his neck. The sword went flying, knocked from Muichiro’s grasp.

A second later, the Upper Moon’s katana impaled his body. The mist returned to him instantly as the demon turned and threw him to the ground, the blade still lodged in his chest.

“You disappoint me, my student.”

—

Yuichiro jumped back as glowing crescents cut through the blood mist, scoring gashes through the snow and slicing through any trees in their path. The hell was that?! It had to have been the Upper Moon’s attack, but they passed by so quickly. If any of them had been targeted at him, he might not have been able to dodge in time.

But soon after, the red mist began to lose substance. It thinned and dropped lower, like a fire suddenly deprived of oxygen. He still couldn’t make out anything beyond the haze, but it was certainly growing weaker.

The implication was obvious. Muichiro was in trouble. He needed to help him.

What can you do? a part of him whispered insidiously. But it was right. Yuichiro was only twelve, his body nowhere near its peak. He couldn’t keep up with a demon like this. One attack could kill or cripple him for life.

Obanai’s words came back to him: Don't go throwing your life away.

But that was his twin on the other side of the mist…!

Something came flying over the fog. Yuichiro stepped to the side and out of the way of the spinning thing as it came down where he stood. He saw his own sword land blade-first into the snow.

A second later, he heard Muichiro’s voice, crying out in pain.

Shock and hesitation vanished. With eyes narrowed in determination, Yuichiro looked to the battle taking place beyond the mist.

He took a deep breath and grabbed hold of his sword.

—

“What would you do… if I tried to kill your brother right now?”

The Upper Moon’s eyes narrowed, his displeasure clear.

“Would you protect him… with such feeble will? As you are… you are too weak… to protect what matters most to you.”

Protect what matters most…

The words stuck in his head. An image surfaced through the fog, of a boy with his face.

Yu…i…

The sword through his chest burned. Muichiro felt hot, fire crackling beneath his skin. His heart thundered. But the mist pressed down, cold and apathetic, trying to smother the heat and flames.

“…Still you refuse to face reality. But no matter… as your teacher… I will correct this mistake.” Upper Moon One pulled his sword from Muichiro’s chest, spraying more blood across the snow. Then he raised it high, flesh blade and eyes glistening in the light of the moon.

The fog closed in around him. Muichiro watched as the blade came down.

Except it didn’t. The eye-covered katana slid against a white blade, knocking it off its course. The boy with his face stood above him, arms shaking with the effort needed to do even that. With a burst of strength, he knocked the sword aside and slashed at the Upper Moon, who simply stepped out of the attack’s range.

“Get away from my brother!” he shouted, even as his voice and hands shook.

A cold feeling gripped Muichiro’s heart, the same as when he’d first seen the demon holding the boy by his throat, claws raised to kill or do even worse. Something frantic pierced through the mist.

Get away! You can’t fight him! He’s too strong!

For a moment, the Upper Moon froze. An unreadable emotion flashed across his face. Then he growled, rage filling his voice. “Do not interfere!”

The Upper Moon swung his sword. Muichiro didn’t even think; he pushed the boy out of the way and threw himself in front of him. The blade slashed deep across his back, almost cutting him in two. The boy with his face cried out and Muichiro smelled human blood. His eyes leapt to his right shoulder, split open and bleeding heavily.

The Upper Moon approached, eyes narrowed coldly. The boy tried to raise his sword, only to gasp and drop it. With an injury like that to his shoulder, wielding a sword would be almost impossible, and he knew it. He picked up the weapon again and abruptly shoved it into Muichiro’s hands.

“Muichiro! You have to fight!” He looked him straight in the eyes, gaze unwavering and determined. Muichiro was too stunned to even wrap his fingers around the sword’s hilt. His hands trembled and he shook his head.

“…I… I can’t-”

“You can! I know you can!” the boy insisted. “I knew all along what the Mu in Muichiro meant! It doesn’t mean nothing!”

The Mu in… His eyes went wide.

“The Mu in Muichiro stands for infinity! For the sake of others, you can summon infinite strength! You’re one of the chosen ones! So fight, Muichiro!”

He covered Muichiro’s hands with his own, pressing his fingers against the hilt, pushing him to take the sword. The young demon shut his eyes tight.

The Mu in Muichiro…

—

…stands for infinity…

The sea of mist churned. It pushed down on him, tried to bury him within the clouds and keep him from surfacing. But Muichiro refused to let it. Not after hearing those words.

Memories began to surface through the haze. Like a cascade, one beckoned more to come forth. Two twin boys, human boys, living in a lonely house on a mountain. The older twin yelling at the younger with tears in his eyes. That same boy throwing himself in front of a monster’s claws to shield his brother. The boys, now a human and a demon, fighting side by side. And the older twin holding the younger one close as a red mist howled around them.

“Let me… let me go! I have to help him!” Muichiro shouted into the sea of clouds.

The mist refused, desperate. It howled, not in words, but in sensations, in thoughts Muichiro knew intimately because they were his own. Stay here! Don’t leave! Here, you are safe! Here, everyone is safe from you!

“No! No, we’re not safe!” Muichiro struggled to make himself heard. There was a threat outside his mind, one he couldn’t beat the way he was now. He pushed back against the fog trying to pull him under.

But the mist would not yield. It roared and turned blood red. Burning heat assailed him. Something stirred in the fog; a shadow appeared before him, features indistinguishable but for its six glowing turquoise eyes.

What can you do?

It spoke in the voice that was his and not his. Muichiro glared back.

“I can fight.”

You can’t win.

Muichiro hesitated. Maybe the shadow was right. Maybe he couldn’t change anything. The Upper Moon One was unlike any demon he’d faced before. But…!

“I can still try. Because Yuichiro is counting on me!”

The Mu in Muichiro stands for infinity!

The shadow’s eyes went wide. Muichiro stood tall and defiant, and it stepped back. The mist cowed before him.

He could do this. His brother was cheering for him. He believed in him.

Yuichiro believed in him!

"I'm not afraid anymore!"

For the sake of others, you can summon infinite strength!

There was a light shining in the distance, past the fog and the shadow of his doubts. Fire rushed through him and burned away the mist barring his path. As its form crumbled to ash, the shadow closed its eyes in acceptance.

Muichiro pushed through the mist, towards the light shining beyond.

—

Muichiro’s eyes, all six of them, snapped open.

His hands grasped the sword’s hilt, and red mist wrapped around the blade. In an instant, he turned and swung, the mist lashing out in a wave that tripled the sword’s reach. The Upper Moon’s eyes widened as he narrowly jumped back, placing a great distance between the two.

“That demon crest… then… you have found yourself...”

Muichiro got to his feet. Anger coursed through his veins. He didn’t care if this was his Teacher; nobody threatened Yuichiro and got away with it. “I won’t let you hurt Yuichiro! Not now, not ever!”

The blood mist rose up around him. Visages of beasts shrieked and roared, echoing his fury towards the demon. Behind him, his brother watched in awe. “Muichiro…!”

Upper Moon One’s face was impassive, at first. Then, almost imperceptibly in the dark, his lips curved into a smile. “Good… then show me… your new power.”

The Upper Moon dropped into a low stance, sword raised. With a grotesque, fleshy sound, multiple smaller blades sprouted along the katana’s length.

“Moon Breathing, Seventh Form: Mirror of Misfortune, Moonlit!”

He swung his altered sword, vertical slashes traveling out across the ground. Muichiro let out a gasp; the elder demon hadn’t shown him this form before. But… he wasn’t afraid. He willed the mist forward, a crimson beast snapping at and swallowing the attack heading towards him, before he himself charged forward at high speed.

But the Upper Moon, faster still, was already following up with another technique.

Moon Breathing, Fourteenth Form: Catastrophe, Tenman Crescent Moon!”

Fourteenth?! Shock washed over Muichiro, but he let it pass, regaining his focus. His eyes concentrated on the Upper Moon’s form, looking past his clothes, his skin. He watched the way his muscles moved, the way his lungs breathed. He could see it all. He could do this. Mist swirled around his brother’s sword.

“Mist Breathing, Fifth Form: Sea of Clouds and Haze, Devour!”

As the hurricane of slashes raced towards him, Muichiro ran forward and swung his sword in a flurry of red mist, cutting through each deadly crescent. The mist moved with him, crimson jaws snapping and tearing through the Upper Moon’s attack, before it converged around him in the form of a large draconic head. It charged forward with a roar, and Muichiro disappeared within it as he picked up even greater speed. The mist dragon crossed the distance in an instant, lunging through the heart of the crescent storm. The force of the slashes ripped the dragon apart, but it succeeded in tearing out an opening for its master. With one final slash, Muichiro burst through the mist and swung his sword at the Upper Moon’s neck.

His sword met empty air. The demon moved at the last second, jumping back some distance away. Muichiro stood tall and held his sword up defensively, his breathing heavy.

Upper One hummed and placed a hand to his collarbone, pulling away with blood on his fingers. The tiny cut had already healed, and yet…

“…Well done, my student.”

Muichiro stumbled forward as his chest suddenly split open, a gash forming from his torso to his shoulder. He choked on his own blood; he hadn’t even realized he’d been sliced.

“Of course… there is still much to learn… but that will come with time.”

“I… I’m not going with you,” Muichiro growled. His body felt heavy, working hard to repair itself. But he knew he wouldn’t be able to stop the Upper Moon. He’d put everything he had into that technique, and the demon still dodged it with such ease. Was it hopeless after all? Even though he’d found the resolve to fight back, were they still going to lose? He snarled and lifted Yuichiro's sword again. He would fight to the end; anything less would be failing his brother.

“Hmm… I had a feeling… you would say that.” The demon stepped towards him. “Unfortunately… my lord-”

The Upper Moon paused, sensing something. Muichiro sensed it too, a powerful presence. A moment later, the older demon dodged as a massive flail slammed into the ground where he’d just stood.

“It would seem the Master’s intuition was on the mark.”

Muichiro looked up with awe at the man who now stood between him and the Upper Moon. A mountain of a man… Muichiro knew him. The Stone Hashira faced down the demon without fear. He pulled on a chain, and the flail dislodged from the ground and returned to his side.

“Then, you must be Upper Moon One.”

The demon did not respond. He studied the Hashira with an unreadable expression. Then he turned his eyes to the sky, where the faintest light was shining in the east.

“…Very well. I will take my leave, then.”

Huh? Muichiro blinked, disbelieving. That was it? After all this, he wasn’t even going to try to fight? But the Upper Moon turned away.

“My name… is Kokushibo. Become stronger… and I will find you again.”

Gyomei grunted, blind eyes narrowing. He swung his flail, but the Upper Moon was already gone. The spiked ball crashed down on nothing but icy snow.

Muichiro relaxed; his extra eyes and demon crest disappeared. Kokushibo; that was his Teacher’s name. Was this whole thing some sort of test? No, he was certain that if Gyomei hadn’t shown up, they would have been in deep trouble. But the Upper Moon was certainly a strange person; Muichiro couldn’t figure him out.

“Muichiro!” The young demon turned around.

“Yui-” Whatever he was going to say was lost as he suddenly found himself in a tight hug, Yuichiro holding onto him as if his life depended on it.

“You’re okay! Thank goodness…! I… I really thought…” Yuichiro shook his head and held him tighter. “He didn’t do anything to you, right?!”

“Yui…” The shock passed, and Muichiro returned the hug. Tears came to his eyes. “N-No, I’m fine…”

“Hu…? Mui, you’re- gah!” Yuichiro jumped back, which turned out to be a mistake as he clutched at his injured shoulder.

“Yui, you’re hurt! You shouldn’t move!” Muichiro gasped.

“Who cares about that?” Yuichiro shook his head. He let go and grabbed Muichiro by his shoulders, heedless of the pain he was causing himself. “You’re you, right? You came back?!”

“Yeah, yeah, I came back,” Muichiro smiled timidly. “Because of you…”

Gyomei knelt down beside them. Even kneeling, he towered over the two. “Tokito, are you injured?”

“It’s not that bad,” Yuichiro tried to brush it off, but Muichiro wouldn’t have it.

“Don’t say that! You’ve lost a lot of blood!” The wound was deep, and it still hadn’t stopped bleeding.

Gyomei hummed. “Do you have any medical supplies?”

“There’s bandages inside the house. I brought some with me when we came here, just in case,” Yuichiro answered.

“Good. Wait here beneath the trees. I will return shortly.” Gyomei stood up and headed towards the house. Muichiro wondered if he’d be okay on his own, but then again, he was a Hashira. If he could fight demons, surely he could find some bandages?

Yuichiro grabbed Muichiro’s hand and pulled him under the shade of the trees. The sky was lightening by the minute, and soon he’d be stuck here. He hoped Gyomei would bring his basket as well.

Yuichiro groaned and clutched his shoulder again. Watching him, Muichiro felt an indignant anger rising up. “What were you thinking? If Teacher wasn’t holding back, he would have killed you! I’m a demon, I can heal! There was no reason for you to put yourself in danger for me!”

Yuichiro looked like he was going to retort, but then he stopped and looked away. He finally spoke in a soft tone, “Yeah, I know. And I'll admit that I didn’t have a plan when I jumped in either. But there was no way I could just stand by while you were in danger. I’m your big brother, remember?”

Muichiro did remember. He looked at the discolored patches on Yuichiro’s face and hands, burns caused by his own Devouring Mist. He remembered that too, and how Yuichiro had jumped right into the mist to try and help him.

He felt ashamed. Yuichiro had never left his side, but Muichiro couldn’t say the same. “Yui, I… I’m sorry. I left you alone for so long, all because I was scared I’d hurt you again. But I just ended up putting you in more danger! We wouldn’t have even been here if it weren’t for me! I’m so sorry…!”

Tears filled his eyes. He shut them tight and bowed his head, not wanting Yuichiro to see him cry. But then he felt a tap on his head. He looked up, and Yuichiro flicked his forehead.

“Ow! What did you do that for?!”

“Dummy,” Yuichiro scoffed, but he was smiling as he said it. “What are you apologizing for? Didn’t I tell you you didn’t do anything wrong?” He looked away, seeming troubled. “I’m the one who should apologize.”

Muichiro’s breath caught in his throat. “Did you mean what you said? About my name meaning infinity?”

Yuichiro nodded. “I did. And, Mui… I’m sorry I said those things to you. After Mother and Father died and left us all alone, I was so angry. But also, I was scared that I might lose you, too. Because of the kind of person you are. You’re kind, and you put other people before yourself, even when it hurts you. But the world is cruel, and no one will protect you. So I thought I had to, even if it meant tearing you down.”

Muichiro stayed silent; he wanted to let Yuichiro say everything he needed to. As Yuichiro continued, his hands balled into fists. “But I was wrong, because those are the same qualities that make you so strong. You were always strong, because you never lost that kindness. I was the weak one; I was the one lashing out because I couldn’t move on from our parents' deaths. You did nothing wrong. As your big brother, I should’ve been honest with you. I understand if you hate me. I thought I was protecting you, but all I did was hurt the only family I had left.”

...That's right, all they had was each other. To think that he had never realized Yuichiro's true feelings until now; Muichiro almost couldn't believe it. They were twins; how could they have misunderstood each other so badly?

“Yuichiro, I don’t hate you,” he finally spoke. “I thought you hated me, because I was so useless. Because I was naive, and cried too much, and couldn’t do anything on my own.”

“That’s not true,” Yuichiro insisted. “I know I made you think it was, but I was wrong!”

Muichiro frowned. It felt strange, wrong almost, to hear Yuichiro say that he was wrong. Once there was a time when his brother’s words meant everything to him, that everything he said was the truth. Because he was older. Even his amnesiac demon self thought the same, always seeking to be equal to his infallible elder sibling. But looking back now, it seemed so silly. Yuichiro was only older than him by a few minutes. He wasn’t any more mature or experienced than he was. But they’d still fallen into the roles of big brother and little brother. And when their parents died, Yuichiro had to step up into a role he wasn’t ready to fill.

“Maybe… we both could have been more honest about how we felt.” Muichiro knew himself. He knew he had a tendency to hide his feelings and avoid conflict. If he had spoken up more, maybe they could’ve had this conversation sooner. “But I get it now. I didn’t realize it back then, but you were hurting too. You’re just… human.”

Humans weren’t perfect. Humans made mistakes.

“It’s not an excuse, though.” Yuichiro muttered.

“No, it’s not…” Muichiro couldn’t deny that. He still remembered the sadness he felt. “…but I understand.”

Yuichiro’s eyes filled with tears. His brow furrowed; he looked so angry. “I’ll be better, I promise! I’ll be the brother you deserve!”

Ah, he was angry at himself; Muichiro’s heart ached. He reached over and gently grabbed his hand. “You already are. You believed in me all this time. Even when I hid inside myself, you stayed by my side. You’ve changed, Yui. I was just too angry to see that before.”

“You really think so?”

Muichiro nodded. “Yeah. Back on the mountain, I was lashing out too. I was so confused and upset; I couldn’t think straight.” He looked up into Yuichiro’s eyes and smiled. “But I’ve had a lot of time to think since then. And I’m going to be better, too. I’ll be someone you can be proud of!”

Yuichiro let out a teary chuckle and shook his head. “You don’t have to do that, Mui; I’m already proud of you. I can’t even describe how proud I am of you!”

Muichiro couldn’t stop smiling, even as tears came to his eyes again. It felt good to hear those words and not be plagued by the uncertainty of his lost memories. He knew now, without a shred of doubt, that Yuichiro meant what he said.

Yuichiro was crying too as he pulled Muichiro into another hug, once again uncaring of his bleeding shoulder. “Can you forgive me? For hurting you?” He sounded so vulnerable, like the kid he really was. That both of them were.

Muichiro nodded. “I forgive you.” He didn’t want this hanging over them any longer. He wanted to move on, to begin the process of healing. “Can you forgive me for hurting you?”

Even ignoring the physical wounds, he had said some hurtful things on the mountain, and left Yuichiro alone when he needed him the most. He wasn’t blameless.

“I told you that wasn’t your fault…” Yuichiro sighed, but his tone of voice carried such fondness. “But yes, I forgive you.”

Muichiro’s smile grew bigger. His heart felt lighter than it had in a long, long time.

Yuichiro sniffed and held him tight. “I really missed you…”

“I missed you, too,” Muichiro hugged him back.

The morning sun shone down around them, pinning him to this one spot. But Muichiro didn’t care; there was nowhere else he wanted to be right now.

He wasn’t sure how much time had passed, but he sensed Gyomei’s presence before the giant’s footsteps settled down next to them. He was surprisingly light on his feet. The twins reluctantly pulled away as he set Muichiro’s basket down beside him and held out the roll of bandages.

“Oh, here! I’ll do it!” Muichiro eagerly took the roll in his claws. He set to work on wrapping Yuichiro’s shoulder up as tight as he could. It was still oozing, but the pressure would hopefully stop the worst of the bleeding.

“Hey, Himejima?” Yuichiro asked as he worked. “Why are you here, anyway?”

“Lady Amane sent me a message that you were coming here,” Gyomei answered. “Since Upper Moon One had found you here once before, she and the Master feared he might target you again. And it would seem they were right.”

“I see…” Yuichiro looked away. He seemed to be thinking hard. “Well, thanks for saving us.”

“Do not thank me. I suspect the Upper Moon fled only because the sun was coming up. If not for that, it is uncertain that even all three of us would have been able to win against him.”

“But then, why did you come after us if you didn’t think you could win?”

“Because that is the duty of a Hashira. Even if victory is all but impossible, we must still fight. I could not idly stand by if there was even the slightest chance I could protect you two.”

“Himejima…” Muichiro was at a loss for words. Even though he was a demon himself, Gyomei still fought to protect him. Yuichiro was similarly speechless, but Muichiro knew that he too was grateful.

“But the Upper Moon’s words concern me. I should inform the Master of what happened here.”

Muichiro knew exactly what he was talking about. Become stronger, and I will find you again; Teacher, Kokushibo, was not done with him.

“We should return to the Butterfly Manor quickly,” Gyomei decided. “Allow me.”

“I can walk on my own- Hey!” Yuichiro shouted as he was suddenly scooped up into the Hashira’s arms.

“It will be faster if I carry you,” Gyomei interrupted, holding him like he weighed nothing. The sight of Yuichiro being cradled like an infant immediately sent Muichiro into a fit of laughter.

“Oh, very funny!” Yuichiro said indignantly. “How about instead of laughing at me, you get in the basket so we can go home? I’m exhausted!”

Muichiro had to agree. With this new awareness of himself came awareness of other things. Namely, how much energy Kokushibo had forced him to expend, and how hungry he was as a result. The smell of blood made his stomach growl, but he forced the hunger back into the depths of his mind. He allowed the mist to engulf it and drag it down beneath the clouds.

Because he knew the mist was not his enemy. It was simply a part of him that protected his innocence, his humanity. But it could be overzealous in its protectiveness. In that regard, the mist was much like Yuichiro. Maybe, in some way, the mist was his brother, always there and protecting him in ways he wasn’t even aware of.

Muichiro returned to his basket and felt Gyomei lift it up. As they began their descent down the mountain, he heard Yuichiro speak.

“You took a while to come back. Did you have trouble finding the bandages?”

“No, I found them easily,” Gyomei answered. “But I had a feeling you two needed some time to yourselves.”

“…Well, you’re not wrong there,” Muichiro could practically hear his brother’s smirk. “Thanks, Himejima.”

Muichiro smiled. He couldn’t wait to go home, back to everyone who was waiting for them.

Chapter Text

Yuichiro couldn’t remember the last time he had felt this content. Muichiro - the real Muichiro - was back and talking to him. Not just broken phrases, but actually talking, full sentences and all. And more than that, he was smiling and laughing again, like when he’d been human, and before their parents had passed away. For the first time in a long time, things felt almost normal.

He knew that wasn’t true, of course. Muichiro was still a demon. He still didn’t age. He still had fangs and claws that could rend flesh and bone with ease. He still couldn’t walk in the sunlight. Things were still very much not back to normal, which was why Yuichiro couldn’t quite say he was happy with how things were now.

But for now, as he walked back to the Ubuyashiki Estate with his brother by his side under the moonlight, he was content. And in this cruel, unfair world, maybe that was enough.

Shinobu forbade Yuichiro from fighting for a few weeks while his shoulder healed. The damned Upper Moon had almost taken his arm off, and it would certainly leave a nasty scar behind. He was glad that she was allowing him to leave the Butterfly Estate after only a week. Perhaps she felt sympathetic and wanted to give him more time to spend with his brother. It was tempting to go back to training as soon as possible, but Shinobu had also promised that if any of his stitches broke, she’d tie him to a bed until he healed. So, best not to push his luck.

Amane was waiting for them at the gate, like she knew they were coming. Maybe she did; the Ubuyashikis were a mysterious bunch, and Gyomei had likely spoken to them about what happened. But Muichiro’s face split into a wide smile at the sight of her, and he dashed ahead of Yuichiro. The young demon jumped and threw his arms around her neck, and somehow she didn’t tumble over from the running force of the hug. But the Master’s wife had always been unnaturally graceful like that; Yuichiro wondered if there was anything that could fluster her.

Amane looked surprised for a moment, then smiled and returned the hug. “Welcome back. How was your trip?”

She spoke in a tone that told him she did indeed know what had happened. Yuichiro grinned and shrugged. “It was… something. But I think it really helped both of us.”

“I’m glad,” Amane said. Muichiro finally let go of her and hopped back, wrapping his arms around Yuichiro’s own arm and leaning his head onto his shoulder.

“Yeah! Yui and I are closer and stronger than ever! Nothing’s gonna stop us when we’re together!”

“Hey, don’t you think you’re getting a little ahead of yourself?” Yuichiro balked. They had only barely survived that encounter with Upper Moon One; he didn’t need Muichiro getting overconfident.

But Amane’s smile only grew, her face seeming lighter as if a great burden had been lifted. “Muichiro… you’ve found yourself. I’m so glad…”

“Um, Miss Amane?” Yuichiro began. She looked at him curiously.

“Yes?”

Yuichiro’s face was turning red and he fidgeted awkwardly. Even after all this time, he wasn’t good with showing sentimentality. “Thank you… for looking out for us.”

It was because of Amane and the Master that Gyomei had come to save them. Yuichiro didn’t even want to think of what would have happened if he hadn’t.

Amane chuckled and shook her head. “There’s no need for thanks. We’re just happy you’re both safe.”

“Yeah, but I want to thank you anyway,” He owed her thanks for so much more than just saving them this time. “And, also…”

He trailed off, not sure if this was the right time to ask. Amane waited patiently, but when he still didn’t speak, she asked, “What is it, Yuichiro?”

“…Is the Master awake? I want to…” he swallowed, thinking one more time if this was what he wanted. If he accepted, their lives were going to change a lot. But one look at Muichiro and his confident, assured smile gave him all the courage he needed. “…I want to give him my answer.”

Yuichiro had never wanted to be a demon slayer. But to make Muichiro human again, he, they, would become a Hashira.

—

“It brings me great joy to welcome a new Hashira to our ranks.”

Yuichiro knelt before the Master, Muichiro doing the same on his right side. Normally the new Hashira would kneel in the sun, between the Master and the current Hashira, but for Muichiro’s sake, the two were allowed to sit in the shade of the engawa. The other eight Hashira watched them with varying sentiments. Most wore neutral expressions, while Kyojuro and Mitsuri were both practically beaming with pride. The only one who seemed displeased was Sanemi, and he didn’t hesitate to make that known.

“Tch, letting a twelve year old kid be a Hashira. He didn’t even kill the Lower Moon on his own; he had his brother to help!”

Yuichiro frowned. He wasn’t wrong, but what was bad about that? They were twins; they were stronger together.

“Now, now, Shinazugawa, I seem to recall you having help to kill your Lower Moon as well.” Shinobu told him with a venomous smile. Sanemi growled, but he didn’t make any further move towards the girl. Likely because the Master was right there.

“I understand your concern, Sanemi,” the sickly man addressed him. “But you need not worry. Because Yuichiro will not be alone. He and Muichiro will take the title of Hashira together.”

At this declaration, every Hashira looked shocked. It was clear that none of them had expected this. Sanemi looked even more outraged. “With all due respect, Master, but you must be joking! A demon, becoming a Hashira?! What if he loses control of himself again?!”

Muichiro fidgeted next to his brother. They’d had no choice but to let the truth come out about what had happened on Mount Takao. Some of the Hashira had their doubts after hearing about it, but the Master’s unshakable faith in the twins had soothed most of their worries. Even still, some concerns remained.

“I have faith that Muichiro’s bond with his brother will allow him to control his instincts. Not to mention, he has fought Upper Moon One to protect Yuichiro, and lived to tell of it. They are both worthy of being Hashira.”

Various expressions of shock and awe adorned the Hashiras’ faces. Yuichiro smiled proudly towards his brother and placed a hand over his to reassure him. Muichiro looked to him with surprise, then smiled and nodded, grateful for his support.

But some of the Hashira still weren’t convinced. Obanai spoke up, a conflicted look on his face. “I’m not sure this is a good idea. Being a regular demon slayer is one thing, but a Hashira? What will the lower members think, seeing one of the demons they’ve sworn to destroy as a pillar of the Corps? Many of them are driven by revenge or a belief in what’s right; this may affect their resolve to fight.”

“Your worries are understandable, Obanai, but I do not believe that will be a concern. The Demon Slayer Corps has persevered in its fight against the demons for a thousand years. While some may feel the way you describe, the majority of the slayers here today will not let their resolve be shaken by this. After all, Muichiro is a demon who is fighting to become a human once again. Does that not demonstrate the inner strength of humanity?”

Obanai had no response to that. It was clear that the Master’s decision was final and that his mind could not be changed on this matter. Sanemi scowled but did not protest further. Met with an accepting silence, the Master turned to address the twins.

“Yuichiro, Muichiro, you are both incredible children. Will you support the Demon Slayer Corps from now on as Hashira?”

The two brothers looked to each other, smiling, then back to the Master. They nodded as one. “Yes!”

“Then we welcome you, as our new Mist Hashira.”

With that, the ceremony came to a close. But before the Master could retire to his room, Yuichiro spoke up. “Master, may I speak to you privately for a moment?”

“Of course,” the sickly man smiled kindly, “Please, come this way.”

“Yui?” Muichiro asked as his brother stood up.

“Don’t worry, Muichiro, this won’t take long. Why don’t you stay out here with the other Hashira?”

“But-”

“Please? There’s something I want to find out.” Yuichiro implored him. “But I promise I’ll tell you later, okay?”

“…Okay.” Muichiro looked worried, but he stayed where he was as Yuichiro followed the Master inside. It wasn’t that he was keeping secrets from his twin, but he didn’t want to worry Muichiro unnecessarily before he had more information.

“What is on your mind, Yuichiro?” The Master asked once they’d settled into the lantern-lit room used for private meetings.

“Master, what do you know of the name Tsugikuni?”

Kagaya’s surprise was shown only in the slightest opening of his eyes. A rare frown graced his lips. “How do you know that name?”

“The Upper Moon One,” Yuichiro answered. “He said that the Tsugikuni family produced the users of First Breathing, and that we were descended from them.”

“I see,” the Master looked troubled, his brow furrowed. “I’m afraid that what I can tell you is limited. Many records of the Sengoku Era have been lost to time, and none remain of the Tsugikuni family beyond that era.”

“But you were able to track us down, right? You knew we were descended from the Tsugikuni family.”

“Indeed, we still possess records of your family tree. The Tsugikuni line continued through one son, whose descendants eventually married into the Tokito family. We traced that bloodline down to you.”

“And who was that son?”

“A man by the name of Michikatsu Tsugikuni. He lived during the Sengoku Era in which First Breathing was created, so we know him to have been a swordsman of that era who wielded the First Breathing. However, that is all I can tell you. No other information concerning him exists in our archive. We were only able to find his name within this one record.”

Yuichiro frowned. That was horribly vague, and he couldn’t help but feel disappointed that the Master didn’t have more to tell him. But he already had his own suspicions. Upper Moon One was a sword wielding demon who lived through that era, and all demons used to be human. Could Upper Moon One have been a Tsugikuni? Could he have even been this Michikatsu? But then that would mean…

That would mean they weren’t descended from heroes, from swordsman who saved people, at all. They were descended from a monster. But it would explain so much, about the demon’s strange interest in them, if they were actually his-

Yuichiro shook his head and tried to calm his pounding heart. No, there was no proof of that. He was getting ahead of himself; there was so little information to go off of that anything could be possible. Upper Moon One might not even be related to the Tsugikuni family at all. He bowed before the Master and his two children and stood up. “Thank you, Master, but I’ve taken up enough of your time. I should be going now.”

“Not at all; you may come to me whenever you need. I only regret that I couldn’t be of more help to you,” the Master smiled sadly.

“It was a long time ago. It can’t be helped.” Yuichiro suspected there was only one person who could give him the answers he sought. But like hell was he going to seek that man, that demon out. The secrets of his bloodline weren’t important enough to risk his life and humanity.

Yuichiro bid farewell to the Master and returned to the courtyard outside, where the other Hashira were crowded around Muichiro. Mitsuri had him in a tight hug, both of them laughing joyously, when she noticed Yuichiro’s approach.

“Yuichiro, you’re back! I can’t believe you’re both Hashiras now!” Mitsuri squealed. “I’m so proud of you!”

She let go of Muichiro and tried to give the older twin a hug, but he simply ducked under her arms. The Love Hashira almost fell on her face, but Muichiro grabbed the back of her haori and helped her steady herself before she could. She breathed a sigh of relief and gave him a grateful smile.

“Indeed! To think you would rise up the ranks in such a short time; I couldn’t be prouder!” Kyojuro smiled. He placed a hand on Yuichiro’s shoulder and shook it. “Let us do our best as Hashira from now on!”

“R-Right…” Yuichiro nodded, suddenly feeling awkward as he tried to find his voice. “Um, Kyojuro?”

“Hm?”

“Th…” He took a deep breath and tried again. “…Thank you. For everything.”

Without Kyojuro’s kindness and support, he doubted they’d have ever made it this far. Kyojuro looked stunned, then his face lit up with the force of the sun itself. He smiled wide and drew Yuichiro into a crushing bear hug.

“You are welcome! And know that, though we may be comrades and equals now, you can always come to me for anything! Whatever you need, you can always count on me to help!”

Yuichiro winced; he thought he felt his bones crack. He tried to free himself from the hug, but gave up after a few moments and decided to just let Kyojuro get it out of his system. Kyojuro was always like this, but no matter how annoying he could be sometimes, Yuichiro wouldn’t have it any other way.

Looking over Kyojuro’s shoulder, he noticed Sanemi standing further off, along with Obanai. The two of them had their gazes trained on Muichiro, their distrust evident. Then Sanemi’s glare wandered his way, and Yuichiro responded by sticking out his tongue.

“Congratulations, you two!” Shinobu stepped in before Sanemi could respond to the affront. “I do hope you’ll be careful, though. You’ll be facing more dangerous missions, and I’d rather not see you at my estate more often than I already do.”

“Don’t worry, we’ll be okay. I’ll be there to keep Yui safe!” Muichiro assured her.

“And I’ll be there to keep you safe,” Yuichiro reminded him pointedly. Muichiro nodded happily.

“Um, Toki-” Giyuu started to speak up, only to stop as Mitsuri let out a high-pitched noise of excitement.

“It’s been so long since we’ve had a full set of nine Hashira! And no one has any missions tonight! We have to celebrate this!”

“A grand idea, Mitsuri!” Kyojuro loudly agreed, finally letting go of Yuichiro. “A feast, perhaps, so that we can all get to know each other better over a fine meal!”

“Eee, yes, that’s perfect!” Mitsuri squealed. “There’s a ramen place in town that serves the biggest portions you’ve ever seen! Iguro took me there once, and it was amazing! Let’s all go there!”

“Sorry, but I don’t think-” Giyuu turned away, only to stop as Shinobu gripped his sleeve.

“Oh, are you really going to walk away when we all finally have a chance to do something together? This is why everyone dislikes you, Tomioka,” she said with a honeyed smile.

“Don’t you dare refuse Kanroji’s kindness, Tomioka,” Obanai said darkly, his words punctuated by a hiss from his snake. “If you try to leave, I’ll drag you back here myself.”

Giyuu let out a suffering sigh and stayed where he was. Gyomei prayed for him, tears sliding down his face.

“Is that really a good idea?” Sanemi asked. “The demon kid’s not exactly good at blending in. People are gonna freak once they see him.”

Yuichiro scowled, but he knew he was right. Muichiro’s glowing eyes were anything but subtle. His twin’s expression was downcast as he muttered, “Sorry.”

Yuichiro shook his head and squeezed his hand. “Don’t worry about it, you can’t help it.”

“Yeah, but…” Muichiro trailed off, still looking disappointed.

“Hmm, in that case, why don’t we have the feast here?” Shinobu proposed. “We’ll use one of the dining rooms here, and a few of us can pick up takeout from in town. That way, Muichiro can move about freely without any worry.”

“Oh, that’s a great idea! What do you think, Muichiro?” Mitsuri asked.

Muichiro stared up at her, surprise clear on his face. Then he broke into a smile, his eyes lighting up. “Yeah! Yeah, that sounds great!”

He bounced up and down, and Yuichiro couldn’t help but share in his excitement. And that was how the two of them got involved in helping the other Hashira to set up for the party that night. There wasn’t much time for decorating on such short notice, but Shinobu, Mitsuri, and Uzui made due with what they could find. Meanwhile, Kyojuro, Sanemi, Obanai, and Gyomei were tasked with picking up the food. Four people seemed excessive, but Shinobu had assured him that it was absolutely necessary.

As he and Muichiro helped with setting up the table, Giyuu approached him again. “Tokito, there’s something-”

“Tomioka,” Shinobu walked up to him, smiling tensely. “Are you just standing around? The boys can set the table on their own. Come, you can help me with something else.”

She dragged him away before he could protest, leaving Yuichiro to wonder what he was going to say. But he soon forgot all about it as he busied himself with the task at hand.

As night fell, the four men returned with the takeout they’d ordered. Yuichiro’s eyes had just about popped out his head at the sheer number of boxes each of them was carrying, Gyomei the most loaded of them all to the point of almost not fitting through the door. The amount of food they were carrying could easily feed everyone in the manor and then some.

“The hell? There’s only ten of us! Who’s eating all this food?!” He asked Uzui, who simply laughed in response.

“Oh, you’ll see…”

Once inside, everyone helped to set food on the large dining table. There was more than just ramen; there was udon, sushi, dumplings, hot pot, piles and piles of rice, a frankly ludicrous amount of different meats and vegetables, and more desserts than Yuichiro had ever seen in his life. He didn’t recognize half of the dishes on the table, probably being expensive delicacies that his family would have never been able to afford. Suddenly he felt like some country bumpkin; he didn’t have the slightest idea where to even start with the food before him.

He looked uncertainly at Muichiro, as if he’d have any more of an idea than him, only to freeze as he caught the look on his brother’s face. Muichiro’s gaze was hollow as he stared at the food, but his expression was one of deep sadness and disappointment. And then, suddenly, it hit Yuichiro why.

I’m an idiot!

They had both gotten so excited, so caught up in this dinner, that neither of them remembered until now that Muichiro was a demon, and thus couldn’t eat any of it. Or maybe Muichiro had remembered, but chose not to say anything so as to not spoil his brother’s excitement. That possibility was honestly even worse. Yuichiro had never wanted to crawl into a hole and die more than he did at this moment.

“Muichiro… I’m sorry,” Muichiro snapped out of his daze and turned to him. “I should’ve remembered.”

Muichiro blinked, then shook his head. “It’s okay. This dinner is to celebrate you. I’m… I’m happy just to be here with you.”

It was obvious he was just trying to put on a strong face; the tears in the corners of his eyes were proof of that. Yuichiro's protective instincts kicked in; he wanted to take that sadness away. The older twin looked into his brother’s eyes with new determination. “No, this is for both of us; we’re both Hashira now! And I promise you, Mui, once you’re human again, we’ll have another feast to celebrate. An even bigger one! We’ll have furofuki daikon, and all the sweets you can stomach, and so much more! You’ll be able to eat anything you want! I promise!”

For a second, Muichiro just stared blankly. Then he smiled and wrapped Yuichiro up in a tight embrace. “Thank you, Yui! Thank you, thank you! You’re the best big brother ever!”

“H-Hey, come on, don’t get huggy in front of the other Hashira,” he whispered, but it was too late. Mitsuri was already cooing over them, while Uzui snickered. Yuichiro sighed and leaned into the embrace; to hell with his reputation.

“Alright, everyone, let’s eat before the food gets cold! It was quite expensive, so we don’t want any of it going to waste!” Shinobu spoke up.

Everyone agreed with that, and took their seats to start filling their plates. Yuichiro and Muichiro sat together, of course, while Mitsuri sat on Muichiro’s right and Kyojuro on Yuichiro’s left. Kyojuro helped to explain what the various dishes were and what he recommended, which was everything, so Yuichiro just grabbed whatever looked good. Meanwhile, Mitsuri piled up plates upon plates of food, taking up both her section of the table and Muichiro’s and Obanai’s next to her. Yuichiro now understood why so much food was necessary.

“Tasty!” Kyojuro shouted next to him, causing the boy to jump. He groaned and tried to focus on his food.

Muichiro shuffled around in his seat, clearly feeling out of place as the only one not eating. He stole a dumpling from Yuichiro’s plate and squished it a bit before popping it in his mouth. Almost immediately though, his face twisted in disgust. He forced himself to swallow and was obviously struggling not to gag.

“Hey, don’t hurt yourself,” Yuichiro gently scolded him, moving his plate out of Muichiro’s reach. “I told you, we’ll get all the food you can stomach once you’re human again.”

“Oh, Muichiro, I’m so sorry! I completely forgot!” Mitsuri shouted, looking distraught. Yuichiro noticed that she’d already eaten through half the plates in front of her; he looked at the stacked up dishes with awe and a little horror. The girl took a break from her food to pull Muichiro onto her lap for a hug. The poor boy looked confused as she sobbed apologies towards him. “Please forgive me!”

“There, there, it’s okay…” he said as he awkwardly patted her arm. Soon Mitsuri’s crying ceased, and she started playing with his hair, something that Muichiro seemed to greatly enjoy.

“Oh, Iguro, look! Isn’t he just the cutest thing you’ve ever seen?” The girl was trying to braid the young demon’s hair as the strands floated around on their own. Muichiro looked at Obanai with large, empty eyes, becoming interested in something on his face. Obanai looked away uncomfortably.

“Um, yeah, cute.” His snake flicked out its tongue and moved closer to Muichiro. The boy noticed and reached out a hand, holding it in place and letting the snake flick its tongue again. It moved closer, and Muichiro slowly brushed a finger across its head.

Mitsuri squealed. “Look, Mui! Kaburamaru likes you!”

Obanai was also stunned by the sight. “Kaburamaru normally hates demons.”

“That’s right, he does!” Mitsuri gasped. “Oh, but if Kaburamaru likes him, then that just proves that Muichiro really is a good demon, right?”

“Y-Yeah, I guess so…” Obanai couldn’t stop looking at the two as Muichiro continued to pet the snake. “…Hey, Tokito, try this.”

Obanai picked up a slice of salmon sashimi with his chopsticks and held it out to the young demon. Curious but also a little cautious, Muichiro took the salmon in his claws and, after a moment of hesitation, popped the whole thing in his mouth.

Yuichiro prepared to lay into the Serpent Pillar for tormenting his brother, but to everyone’s surprise, Muichiro didn’t react in disgust as he usually did. He swallowed the fish and his face lit up.

“It’s bland!” he exclaimed with the biggest smile on his face. “It’s completely tasteless!”

Despite his objectively negative statements, he immediately reached for the rest of the sashimi and started piling it on his empty plate. Mitsuri beamed and turned to Obanai.

“Iguro, how did you know?”

“Sashimi is raw fish. I thought he might handle it better than the cooked food. Didn’t the boy eat rabbits when he first turned?”

He directed that question at Yuichiro, who nodded. He’d forgotten that Muichiro could eat uncooked animal meat, even if it didn’t satisfy him. But he was grateful to Obanai for thinking of it. Muichiro looked so much happier now, being able to eat with the rest of them.

“Thank you, Iguro!” the young demon said with a smile as bright as the sun.

Across the table, Sanemi shot the Serpent Hashira a betrayed glare. Obanai avoided making eye contact with him.

Kaburamaru slithered off Obanai’s shoulders and moved to sit closer to Muichiro. He gasped softly in excitement. “Yui, Yui, look!” he whispered, wanting his brother to see. Yuichiro smiled and nodded.

“Good for you, Mui.” His brother always did like animals. “Just don’t get too attached; Ginko will throw a fit if she sees you.”

Muichiro's eyes went wide at the realization, and he began looking around as if expecting the jealous crow to come flying in at any moment. It was an amusing sight, and Yuichiro couldn’t help but chuckle.

“So, kid, did my advice help after all?” Yuichiro stopped laughing and looked at Sanemi, who was seated directly across from him, between Gyomei and Shinobu. He frowned; as much as he loathed the idea of owing the Wind Hashira, his advice had indeed been the key to bringing Muichiro back. But he was petty and he was not going to just admit that.

“Yeah, it did. Guess you’re good for something besides stabbing kid brothers after all,” he snarked, smirking as he did so.

A vein bulged in Sanemi’s forehead as he leaned over the table with a glare. “You want a fight, you shitty brat?”

“Like you could even touch me, you scar-faced bastard!” Yuichiro leaned forward as well, refusing to be looked down on.

“Big talk for a five year old!”

“Says the guy with white hair! How old are you, anyway?”

“You little-“

“Careful, old man. Wouldn’t wanna raise your blood pressure, would we?”

Giyuu spoke up quietly. “Um, Tokito, can I-”

“Shut up, Tomioka!” Yuichiro and Sanemi yelled at the same time before going right back to glaring daggers at each other. Giyuu blinked, then slumped in his seat dejectedly.

“Yui, maybe you should stop…” Muichiro said with a bit of panic in his voice.

“I agree! As much as I respect your skills, a fight with Shinazugawa will not end well!” Kyojuro added before he took another bite of food. “Tasty!”

“This poor child… I pray that he is not hurt too badly…” Gyomei sniffed.

“Tasty!”

Yuichiro sat back down and scowled. “Thanks for the vote of confidence, guys.”

“Tasty!”

“I think he has a chance!” Mitsuri said, ever the optimist.

“Tasty!”

“Don’t encourage him, Kanroji,” Obanai muttered.

“Tasty!”

“Can we please have a normal dinner?” Shinobu sighed, her smile more forced than usual.

“Tasty!”

Yuichiro groaned and slammed his head on the table. “Do you have to say that after every bite?!”

“Heh, you’ll get used to it, kid…” Uzui said with a shrug. “…Eventually.”

Muichiro burst into laughter. Yuichiro lifted his head and looked at him quizzically.

“I like them, Yui,” his twin said simply, eyes shining with mirth.

Yuichiro smiled back. “Yeah, me too.”

The Hashira were beyond weird, but they were all good people. They’d gone through the trouble of throwing this party to make them feel welcome, after all. And many of them had looked out for the twins over these past months, keeping them safe in their own ways. Shinobu, who always lent an encouraging ear. Obanai, whose words brought him back from a pit of despair. Gyomei, who put his life on the line against an overwhelming opponent. Even the others, who he saw less of, tried their best to bring Muichiro back. The two of them hadn't even been Hashira yet, but they had cared for the twins anyway. He felt that, with time, he could get used to them.

Not Shinazugawa, though. Fuck that guy.

—

The twins left for their new estate late that night, aiming to make it there before the sun rose. Muichiro couldn’t stop fretting over Yuichiro, who nursed a black eye courtesy of the Wind Hashira. They’d ended up getting in a fight after all, and as much as Muichiro loved his brother, he had to admit he’d been way in over his head. He should’ve seen it coming; Sanemi was older, taller, and had a lot more experience as a fighter. Not to mention his still healing shoulder; of course it would be wholly one-sided.

But Yuichiro didn’t care about his eye or the bruises he’d have in the morning. He’d managed to leave Sanemi with a broken nose, so he had no regrets.

“Yui…”

“I’m fine, Mui. It’s no big deal. It barely even hurts.”

That was a lie; Muichiro had to help support him on his right side as they walked. It was a good thing they had no missions anytime soon. But thankfully, it wasn’t much longer before the newly-named Mist Estate came into view. The two brothers crossed the bridge going over a shallow stream and walked through the gate into the courtyard.

It was here that Yuichiro gently pushed his brother off of him. “I can walk by myself, Mui.”

Muichiro was still concerned but didn’t push it, and soon he found himself distracted with exploring their new home. It was large, though not as large as the Master's manor, and it was plain that no one had lived here for quite some time. Muichiro wondered if they could have some trees or flowers planted to brighten it up. It hit him suddenly that they would be living on their own again. He’d gotten so used to having other people around, whether it was at the Ubuyashiki or Butterfly Estate. He was already starting to miss the Master, Amane, and their kids.

Muichiro came out of his wistful thoughts in time to see Yuichiro walking inside. He stiffened, then quickly followed after him. The inside of the manor was clean, well-kept, and far too big and empty for only two children to live in. He looked to Yuichiro, who was deep in thought with a troubled expression on his face.

“Yuichiro? Is something wrong?” Muichiro asked, tilting his head.

“This place is… pretty big, isn’t it?” He asked. It was clear that he was thinking the same thing Muichiro was. “It’s dark and empty, too.”

Muichiro hummed and looked around, knowing exactly what he meant. He glanced back at his twin with a cheeky grin. “Huh, I didn’t really notice. It looks bright enough to me.” But Yuichiro didn't seem to notice his attempt at lightening the mood; he just nodded and stayed silent.

Muichiro leaned in close, a more easygoing smile on his face. “Hey, let’s light some lanterns and put up decorations. That’ll help liven it up, right?”

Yuichiro smiled back. “Decorations, huh? Like what?”

“I’ll make origami while you’re sleeping. I’m sure I can find some paper around here somewhere.”

Between the ceremony and party, it had been a long day. It was clear to him that Yuichiro was barely staying awake at this point. The involuntary yawn he gave only proved his point. “Sure, that sounds great.”

Muichiro giggled and led him down the hall, searching for the washroom and bedroom. Yuichiro lethargically prepared for bed at his prompting, already half asleep. There were only a few hours left until morning, so he hoped his brother could get some rest. Today was their first real day as Hashira, after all; he needed all the energy he could get.

As Yuichiro laid down on the futon in their new bedroom, Muichiro shuffled through the dresser. “Yui, there’s paper here!”

“That’s great…”

Muichiro chuckled. He walked over and sat beside his brother, watching him drift off. “Hey, Yui? I know it’s weird, having this big place for just us two. But give it time. I’m sure we can make it feel like home. So don’t worry, okay?”

“Yeah, yeah…” He was barely listening at this point. “Just let me sleep…”

Muichiro giggled again. He was glad that his brother felt comfortable enough to sleep on his own again, without Muichiro at his side. Or maybe he was just that tired. “Alright, I get it. Good night, sleepyhead!”

He stood up and left. As he closed the sliding door behind him, he heard Yuichiro mumble, “Good night, Mui…”

Muichiro smiled as he walked down the hall, origami papers in hand. He found the dining room and spread the papers out across it, wondering what he should make. But before he could decide, his gaze wandered to the window, where a full moon shone down on the garden outside.

Something about that moon called to him. Muichiro felt a sudden urge to move, like he had too much energy inside him. He left the origami behind as he made his way outside. There were still hours until morning came; he could decorate later. The young demon wandered out into the garden and stared up at the moon.

After a few moments, he looked away. The young demon glanced around, part of him expecting to see bright yellow eyes gazing at him from some hidden spot, but he was alone here. Why was he thinking about that man now? His Teacher, the Upper Moon One. Part of him knew he shouldn’t think of the enemy in such a reverent way, but he couldn’t help it. Kokushibo was the reason he could use Total Concentration Breathing, which had undoubtedly allowed him to protect Yuichiro. He still wasn’t sure why the ancient demon had such a vested interest in him, but he couldn’t deny that Kokushibo had helped him become stronger.

A mist sword formed in his right hand. Muichiro held it up against the full moon, watching the silver light filter through the white haze. He took a deep breath.

“Moon Breathing, First Form…”

He moved the sword to his left hip, as if preparing to draw it from its sheath. He stood strong with his feet planted firmly on the ground.

“Dark Moon, Evening Palace.”

The mist blade swung out in a horizontal arc, faster than the human eye could follow. Foggy wisps in the shape of crescent moons leapt from the main slash, glowing silver as they cut through the air with a swift and dangerous elegance.

Muichiro smiled. He had worried he’d be out of practice after so long hiding inside himself, but his body remembered. It remembered Moon Breathing, the breathing style that Kokushibo could never teach to anyone else. His wisps of fog weren’t quite like the beautiful glowing crescents of his Teacher’s blade, but they were his own. He could learn Moon Breathing, and make it his own. He could become even stronger to protect Yuichiro and the innocent humans who needed him.

Muichiro lifted his sword and prepared to continue his training when a soft voice spoke up to his right. “Tokito?”

Muichiro spun around with his sword pointed at the intruder. He’d been so absorbed in his thoughts he hadn’t sensed him come near, but he soon relaxed upon seeing who it was. “Oh, Tomioka! What are you doing here?”

The Water Hashira blinked at him, looking closely. “…Oh, you’re the other one.”

Muichiro blinked back. “Yes?” He figured that was obvious, with his white clothes and the sword made of mist that was still in his hands. Maybe Tomioka needed glasses. “Did you need to speak to my brother?”

Again, Giyuu took a while to respond. “…No, you’ll do. There’s something I have to tell you. On my last mission, I found something.”

Found something? Muichiro let the sword vanish and listened.

“I found another demon like you.”

—

Somewhere far away, Upper Moon One looked up to the full moon. Glimpses of another’s memories, scattered and fleeting, flashed before his mind’s eye. A serene garden at night, and an arc of mist in the shape of a crescent moon. The first form of Moon Breathing was unmistakable; he felt the happiness and sense of accomplishment from the one who performed it.

His student’s pride was infectious. Whether the boy knew it or not, they shared a profound connection. They were bound by blood, both in the familial sense and by the demonic blood that ran through them both. A small smile came to Kokushibo’s face.

He recalled that night, the night in which he knelt and pleaded to his Master. He could and should have been destroyed for his failure, a failure that was entirely his own doing, but being Muzan's longest-lived ally counted for something. And he was adamant that his decision to turn the boy had not been wrong. He was a special talent. One blessed by the gods.

“My Lord, I request that… you allow those children to stay with the demon slayers.”

Just like…

“The boy displays explosive growth… when driven to protect his brother. He will surely grow stronger at his side.”

No, Kokushibo refused to think about that any further. That was in the past. The boy, Muichiro, was here now.

“And should he survive… the boy’s brother will also become stronger.”

As was Yuichiro. Though not blessed like his twin, he had trained and earned his skill. Kokushibo had been a fool to dismiss him before. Had he not been in that same position once himself, passed over for a sibling who was more talented?

“Until the time comes when they are needed… allow them to grow freely. I believe that… only in this way… will they be of the greatest use to you, my Lord.”

Kokushibo watched the full moon as the night continued to pass. When would that time come? The time when Ubuyashiki would be found, and his lord would wipe out the Demon Slayers once and for all? But he was not impatient to find out. He had lived four hundred years already; he could wait more.

For now, he was content to watch from afar.

“Become stronger, my descendants.”

Chapter Text

Yuichiro woke up the next morning bruised and sore. It took his sleepy mind a minute to remember how that happened, and when he did, his mood immediately soured. Damn that Shinazugawa. So cocky, just because he was older and stronger and had years more of experience… okay, fine, Yuichiro had been stupid to fight him. But one day he’d be an adult too. Then he’d show him.

At least he’d broken his nose, so it wasn’t a complete loss.

Yuichiro ignored the aching in his body as he got up to start the day. They were on their own now in their new Estate, and someone had to cook breakfast. Gods knew it wasn’t going to be Muichiro, who couldn’t cook to save his life even before becoming a strict carnivore. So when he opened the sliding door and was met with the scent of cooking fish, he was immediately concerned. Was there someone else in the manor?

He hurried to the kitchen, and was immediately met with one of the last sights he ever expected to see. Giyuu Tomioka stood at the stove, grilling salmon with a pot of miso soup boiling beside him. He worked quietly and efficiently; Yuichiro wasn’t sure if he even knew he was there or not. But the new Mist Hashira was at a loss for words, just standing and staring as the Water Hashira used his kitchen to make breakfast.

“Oh, Yui, you’re awake!” Muichiro’s voice caused Yuichiro to snap out of his thoughts with a jump. He turned to see his twin run up to him, a dark blue piece of origami in his hands. He held it up to his brother. “Look, it’s a fox! What do you think?”

Yuichiro peered at it closely. He didn’t have the best eye for this sort of thing; his skills with origami were a lot more basic than his brother’s. But he could see the resemblance, so he nodded. “Looks good.”

Muichiro beamed at his approval. Yuichiro looked out the corner of his eye back at the Water Hashira, who still hadn’t acknowledged him. “Um… Mui?”

“Yes, Yui?” his brother asked innocently.

Yuichiro knew Muichiro was more spacey ever since becoming a demon, but sometimes he wondered if he did this on purpose to mess with him. “Why is Tomioka in our kitchen?”

“He’s cooking breakfast.”

Yeah, he was definitely messing with him. “Muichiro.”

Muichiro burst into laughter. “Sorry, sorry! I couldn’t help it! You looked so funny; Nii-san never looks surprised like that!”

Yuichiro blinked. “Nii-san…?” It had been a long time since he’d heard Muichiro call him that. Since before he became a demon, in fact. But he didn’t dislike it; on the contrary, he felt warm hearing that name again.

But Muichiro suddenly looked unsure. “Do you not wa-”

“Nope, don’t finish that,” Yuichiro interrupted with a smile. “You’re my little brother. You can call me whatever you want.”

His twin smiled back and nodded. “Okay!”

“Breakfast will be ready soon,” Giyuu spoke up suddenly. “Go sit down; I’ll bring it out shortly.”

So he did know he was there. The least he could’ve done was say hi. Yuichiro understood now why Sanemi and Obanai disliked the Water Hashira so much. He didn’t care for social niceties much either, but at least he made an effort when around other people. To not even try just spoke of arrogance.

He followed Muichiro back out into their dining room. The curtains were closed to keep out the sunlight, and the table was littered with all kinds of origami animals. Cranes, cats, frogs, even tigers and dragons. It was honestly impressive.

“You’ve been busy,” Yuichiro noted.

“Thanks, but there’s only so much I can do with what we have here,” Muichiro said as he set the paper fox down on the table. “Can we go into town later for some paper lanterns?”

“Yeah, sure. I’m sure there’s more stuff we have to get anyway.” The gears were already turning in Yuichiro’s head as he pondered what they needed to buy. Clothes, food, and other necessities. There wasn’t much that was truly their own that they were able to bring from the Ubuyashiki Estate. It was a good thing that, as Hashira, they now had a nearly unlimited budget to buy everything they would need to make this place a real home.

Muichiro smiled and began to clear the table of his origami crafts. He looked very happy, but maybe that was just the excitement of starting their first official day as Hashira. Yuichiro himself was certainly less excited, in part because he was still very confused. “So… are you going to tell me why Tomioka is here?”

Muichiro’s smile fell as he looked thoughtful. “He came by last night after you went to bed. He had something really important to tell us, so I invited him to stay until you woke up.”

“What could be so important that he had to follow us home?” Now that Yuichiro thought about it, he did remember Giyuu trying to talk to him multiple times before and during the Hashiras’ welcome party. Did it have something to do with that?

“I think it would be better to let Tomioka explain it himself,” Muichiro said. So his brother already knew, and whatever it was, it was something that he didn’t want to spill immediately to his older brother. It must be serious, then.

Giyuu still hadn’t come out, so the boys sat at the table in silence. Muichiro started folding another piece of paper. Yuichiro fidgeted and kept glancing towards the kitchen.

“So, how’s it been, anyway? Hanging out with Tomioka?” He had to imagine spending time with the Water Hashira was about as stimulating as talking to a vase.

“Uh… he doesn’t say much.” Muichiro admitted. “But that’s okay, since I’m the one who asked him to stay.”

Yuichiro rolled his eyes. “You’re too-”

“Here. It’s not much, just rice and salmon with miso soup.” Giyuu said as he walked out with two plates. “You don’t have much to work with.”

“Well, we haven’t had the chance to go shopping yet.” Honestly, Yuichiro was surprised they even had this much. The caretakers must have prestocked their food supply before they arrived.

Giyuu set one plate in front of Yuichiro and the other in front of himself as he sat down. Muichiro continued to busy himself with the origami, pointedly avoiding looking at the hot, fresh food. Yuichiro felt guilty, but he couldn’t deny that the breakfast smelled amazing. Simple as it was, it was clear Giyuu knew his way around a stove. For a while, the room was silent but for the clink of their chopsticks as they ate. But soon the food was finished, and Yuichiro couldn’t contain his curiosity any longer. “Tomioka, why did you come here?”

Giyuu closed his eyes in thought. “There’s something I need to tell you.”

“And you had to show up in the middle of the night to do it?”

“Well, I tried to tell you earlier…”

Yuichiro grimaced. So that was why he was trying to get his attention at the party. “We were busy, and you need to speak up better. You could have told us before we left, too, instead of sulking like some kind of weirdo.”

Giyuu looked a little sad at his words, like a kicked puppy, and Muichiro shot him an empathetic glance. The older twin groaned. “Ugh… Fine. I'm sorry, I guess." He quickly realized how insincere he sounded, mostly because he was insincere, and gave up trying. "...Anyway, out with it. What did you need to tell us?”

“On my last mission, I came across a boy and his sister who’d just been turned into a demon.”

Yuichiro frowned and immediately looked to his brother to gauge his reaction, but Muichiro just watched patiently. That’s right, Muichiro already knew, and he was just having the blanks filled in. “Well? What about them?”

“The boy was trying to protect his demon sister. Of course, that’s not unusual, though he did try to fight me.”

“What a bold idiot,” Yuichiro scoffed. It made him a good big brother, and Yuichiro had to respect him for that, but he was a still a total idiot. A civilian stood no chance against a Hashira. “So what? Did you kill the demon? Where’s this boy now?”

“No, I let them live.”

A pause. “Huh?”

“After I knocked the boy out, the demon girl leapt at him. I thought she would devour him, but instead, she protected him from me.”

Yuichiro was stunned. A demon that protected a human? “But that means-”

Giyuu nodded. He turned to Muichiro. “She was like you.”

Yuichiro felt his heart beat faster, his whole body filling with some kind of emotion. Excitement? Anxiety? Of course he knew that it had to be possible for another demon like Muichiro to exist, but he never actually considered that it might happen. He’d fought and heard of so many vile demons that his brother felt like a one-of-a-kind occurrence. To know, for certain, that there was another demon like him out there was world-shaking.

“Where are they now?!” he asked suddenly, louder than intended.

“I sent the boy to find my old cultivator, Sakonji Urokodaki, in order to train him. He should be with him by now.” Giyuu stood up abruptly as he said that. “I’ll write down the directions for you if you want to see him, but after that, I need to be going.”

“Have you told the Master yet?” Muichiro asked.

“I sent my crow to deliver the report.”

The younger twin frowned. It was well-known that Giyuu’s crow was old and had a tendency to get lost or deliver messages to the wrong address. “Maybe I’ll have Ginko deliver a message too, just in case.”

Giyuu nodded and grabbed the empty plates and a piece of origami paper before leaving the room. Yuichiro was once again put off by his cold refusal to engage in any social interaction past what was necessary. But then again, Giyuu had gone the entire day and night without sleeping thanks to the party. He could just be tired. And he’d thought to share this information with them, so maybe Yuichiro could give him the benefit of the doubt just this once.

True to his word, Giyuu wrote down the directions to his cultivator’s home and swiftly departed from the Mist Estate. The twins watched him go and then turned to each other.

“Yui-” Muichiro looked at him pleadingly.

But Yuichiro didn’t need any convincing. He nodded. “Mui, pack up. We’re going now.”

—

They found the home of Sakonji Urokodaki just as the sun was starting to dip below the trees. While it was a lengthy distance from the Mist Estate to begin with, progress had been slower than usual. The two traveled only during the daytime, retiring as soon as the sun set. Part of the reason why was because Yuichiro was still recovering and it would be unwise of him to fight any demons right now. The other part was an ever-present fear in them both that Upper Moon One would come for them again.

That fear was understandable, but still humiliating. Yuichiro hated hiding from the dark like this when they were supposed to be demon slayers, Hashira even, but Muichiro reassured him it wouldn’t be forever. Once he recovered, they would resume their duties. And besides, they weren’t here to fight.

Urokodaki’s house was located at the base of a tall mountain, deep inside a forest. It was quaint and reminded Yuichiro of their old home. The door was closed and no one answered when he knocked.

“Nothing,” he grumbled.

“Maybe they’re out training?” Muichiro suggested.

That was probably the case. Yuichiro sighed and took Muichiro’s basket off his shoulders, setting it on the ground before leaning against the house. There was nothing to do but wait, then. But luckily they didn’t have to wait long, as soon he heard the sounds of someone coming up the path. He looked over and spotted an aging man in a blue, cloud-patterned kimono carrying two buckets full of water. His face was covered by a red tengu mask; he matched the description given by Giyuu perfectly.

“Are you Urokodaki?” Yuichiro asked, moving to meet the man halfway.

The man’s surprise to see him was short lived, and he nodded. “I am. You must be the Mist Hashira then. Giyuu told me you would be coming.”

Yuichiro nodded back. “My name is Yuichiro Tokito. Tomioka told me that you’re training the boy with a demon sister. Is that true?”

“I presume you are speaking of Tanjiro Kamado? Yes, he is in training under my instruction to become a demon slayer.”

Tanjiro Kamado; so that was the boy’s name. “Is he here?”

“I’m afraid you just missed him. He is up on the mountain as part of his training, but he should be back before morning.”

Yuichiro frowned. He had really hoped to speak with the Kamado boy right away. He wasn’t keen on waiting after having come all this way.

“You are welcome to stay the night and wait until he returns,” Urokodaki offered.

They didn’t really have a choice; it was too late to walk back to town before nightfall. “We’ll take you up on that offer. Thank you.”

“There’s no need for thanks. I’m grateful for the company.” Urokodaki walked past him to his home, and Yuichiro followed. The older man cast a glance at Muichiro’s basket as he passed by, but he didn’t say anything. Yuichiro grabbed it and carried it inside after him.

The inside of the house was just as modest as the outside, but it felt warm and lived in. Yuichiro set the basket down and tapped on it, and Muichiro slipped out in a cloud of mist. Urokodaki watched this with interest, or as much interest as could be conveyed by an expressionless tengu mask.

“Giyuu had told me about the demon amongst the Hashira, but I must admit that seeing you in person is quite the surprise. Nevertheless, you are welcome here.”

Muichiro grinned. “Thank you, Mr. Urokodaki! It’s nice to meet you!”

“The pleasure is all mine.”

Yuichiro frowned. “So Kamado’s not here. What about the demon girl?”

“You certainly don’t waste time, do you?” Urokodaki shook his head. “But to answer your question, Nezuko is asleep in the spare room. I should warn you, though, that she has been sleeping for a while, with no signs that she will wake soon. So if you were hoping to speak with her, you may be disappointed.”

“How long is a while?” Yuichiro tilted his head.

“About three weeks now. She fell asleep shortly after arriving here and hasn’t woken up since.”

Three weeks? Both twins were surprised to hear that and exchanged glances. Demons didn’t even need sleep; to sleep for three weeks straight was very strange.

“Can we see her anyway?” Muichiro asked tentatively.

“Of course. This way,” Urokodaki said as he led them down a small hallway to a room at the very end. He quietly slid the sliding door open and stepped inside, and the two brothers followed.

The spare room was very dark, curtains drawn shut, and the reason why lay in the center of the room. A young girl, probably not any older than the twins themselves, slept peacefully beneath a futon. She had long brown hair that turned bright orange near the tips, and a bamboo muzzle was strapped over her mouth.

Muichiro stepped closer and knelt down beside her. He almost seemed to be in a trance, staring unblinkingly at her sleeping face. He didn’t say a word. Yuichiro felt he ought to give him some privacy; there wasn’t much he could say to a sleeping stranger anyway. Quietly, he stepped out of the room with Urokodaki, shutting the sliding door behind him.

—

Muichiro vaguely registered that he was alone now. But he still couldn’t take his eyes off the girl.

She’s pretty.

She looked soft and peaceful as she slept, so very unlike what would be expected of a demon. If he didn’t know better, he could almost believe she was human.

Her scent was different from the usual demon too. Most demons smelled of blood, of the death that they caused. But this girl, Nezuko, smelled pleasantly of flowers, with the slight smoky scent of charcoal underneath. He was reminded of a sunny day, which was strange, since he could scarcely remember what it felt like to bask beneath the sun. Suddenly he felt sad, both for himself and this girl who could no longer walk in the sunlight either.

Slowly, Muichiro reached out and brushed a lock of hair away from Nezuko’s face. “Can you hear me…?” he whispered.

But Nezuko didn’t so much as stir, remaining utterly still but for her soft breathing. Muichiro tried to gauge any insight from her sleeping face. Was she dreaming? What was she dreaming about? Muichiro's own dreams were foggy at best. Even when he was in the throes of a nightmare, he’d forget the details within minutes of waking up, recalling only the feeling of terror. He was sure he used to remember his dreams better when he was human, and wondered if it was the same for Nezuko. He had so many questions for her.

But Nezuko continued to sleep, oblivious to his presence. Muichiro laid down on his stomach and rested his head on his arms. Watching her was making him feel sleepy too, somehow. Or maybe he was tired because he hadn’t eaten in days. The mist in his head beckoned him to rest.

Well, it would be a long while until Tanjiro returned. He doubted Yuichiro would mind if he took a nap to pass the time.

—

Yuichiro sat in the living room with Urokodaki, quietly drinking tea that the cultivator had just prepared. “So what’s this Kamado kid like, anyway?”

“Tanjiro is a good boy, earnest and hardworking. He certainly has promise.” Urokodaki explained. “Still, his training has only just begun. It remains to be seen if he can handle it.”

Yuichiro nodded. “Well, if he really wants to help his sister, then I’m sure he will.” Muichiro was the one thing that kept him on this path, the one reason he was a demon slayer at all. As another older brother, he was sure Tanjiro must feel the same way about Nezuko.

Time seemed to tick by agonizingly slowly. He absentmindedly rubbed his aching shoulder and wished the night would pass faster.

“Care for a game of shogi to pass the time?” Urokodaki asked suddenly.

Yuichiro was caught off guard by the question, but once it registered, he nodded and waited while the board was set up. Hours went by as they did little but play game after game. Urokodaki turned out to be quite skilled, but Yuichiro was no slouch either. Each match lasted over an hour, and they were on their seventh match, three for three, when the front door suddenly opened.

Yuichiro looked up to see a boy around his age, panting heavily and bending at the knees, ready to fall over from exhaustion. He had brownish-red hair and a scar on his forehead, and wore a green and black checkered haori and a pair of hanafuda earrings. He was covered in dirt, scrapes, and bruises. What kind of training was he doing on that mountain?

Yuichiro opened his mouth to say something, but then the boy lifted his head, and the words died in his throat. He had red eyes. Red eyes as bright as a flame. Red eyes that shone with the gentle warmth of the sun. Red eyes that were strikingly and painfully familiar. This boy…

This boy had the same red eyes as his father.

“Urokodaki… I did it… I-” Finally noticing Yuichiro’s presence, the boy froze and tried to look steadier than he was. He wasn’t doing a good job of it, though, still looking like he was about to keel over.

“Tanjiro, this is Yuichiro Tokito, the Mist Hashira of the Demon Slayer Corps,” Urokodaki introduced him.

“A Hashira…?” Tanjiro looked confused, then realization struck him, and he bowed his head, “Oh, that’s right! Please forgive me, Lord Tokito! I’ve been so busy that I completely forgot you were coming!”

Yuichiro was still in such shock that he didn’t even register what the boy was saying until he heard his name. He jumped back to reality and turned away, trying not to look at his face any longer. An unsettling feeling of nostalgia settled in his stomach, making him nauseous, and he fought to keep a straight face.

“So you’re Tanjiro Kamado, then? The boy whose sister was turned into a demon?”

Tanjiro immediately stood tall. He wasn’t hostile, but his body betrayed his wariness. He was unsure of this newcomer's intentions and was ready to fight for his sister if it became necessary. Yuichiro knew that because he recognized himself in that guarded pose.

“We’re not here to hurt you,” Yuichiro clarified. “We’re just here to talk.”

“We?” Tanjiro repeated. Suddenly they heard the sliding door in the back of the house open, and Tanjiro’s face lit up. “Nezuko?”

With an expression of shock and hope, he rushed down the hallway. Yuichiro jumped up and followed after him, but Tanjiro didn’t get far before he stopped. Muichiro stood in front of him, wiping his eyes and looking like he had just woken up from a deep sleep. For a second, Tanjiro’s shoulders slumped. He seemed to have been hoping that his sister had finally awakened; Yuichiro could sympathize with that. But he recovered quickly, and greeted Muichiro with a cheerful smile. “H-Hello there! You must be the other Mist Hashira!”

Muichiro nodded sleepily and pulled his sleeves away from his face, allowing Tanjiro to see his eyes for the first time. They made eye contact, and both went utterly still, identical looks of shock on their faces.

“Huh?” Tanjiro breathed. “You’re-”

Muichiro cut him off, getting right up into his face and peering deep into his eyes. He said nothing. Yuichiro moved around them, and noticed Tanjiro’s gaze fogging up the longer he looked into Muichiro’s own. Yuichiro rolled his eyes and sighed. “Mui, you’re doing it again.”

He grabbed his brother by the back of his kimono and pulled him away. Muichiro stumbled as he was abruptly brought back to reality, and Tanjiro snapped back to himself as well, looking around wildly in confusion.

“Sorry about that,” Yuichiro muttered to the baffled teen. “He has a tendency to stare.”

He looked to Muichiro, who was indeed staring again. Yuichiro elbowed him in the arm, not too hard but enough to shock him awake again. His twin quickly bowed his head, face turning red. “S-Sorry!”

“It’s okay, don’t worry about it!” Tanjiro laughed it off. “I don’t know what came over me…”

“No, it was my fault,” Muichiro shook his head. “Eye contact with me makes other people feel all… um, foggy. It’s not something I can turn off, either. I should’ve been more careful.”

Tanjiro frowned, looking thoughtful. “You’re a demon, aren’t you?”

Muichiro nodded. He looked worried, likely expecting Tanjiro to be afraid of him, but the other boy looked more curious than anything. “You don’t smell like other demons. Why is that?”

“Smell?” Yuichiro repeated, already feeling irritated again.

“Sorry, I didn’t mean it as an insult. I’ve always had a really keen sense of smell. What I mean is that demons usually smell of blood, but you don’t smell like that. It’s hard to explain, but it reminds me of Nezuko.” He suddenly realized something. “Oh, you were just in there with Nezuko, right? Is she okay?”

Muichiro nodded. “She’s still sleeping, but she’s fine.”

“And to answer your question, it’s probably because Muichiro hasn’t eaten any humans,” Yuichiro said to steer them back on track. He had waited long enough to talk to the boy and his patience was wearing thin.

“Really? There are other demons who don’t eat humans?” Tanjiro looked shocked.

“Well, there are a few demons that are good...” It came down to what one considered to be “eating humans”. Tamayo and Yushiro didn’t hunt, and they didn’t hurt anyone, but they still needed to consume human blood to sate their hunger. “But until recently, we thought Muichiro was the only one who had never eaten a human at all.”

“Wow, that’s-!” Tanjiro was cut off by his stomach rumbling loudly. He blushed, embarrassed, while Muichiro giggled and Yuichiro rolled his eyes.

“S-Sorry, it’s been a long night for me,” Tanjiro apologized. “Would you like to join us for breakfast? We can talk more over a meal.”

There was something about the way he spoke, a certain tone that made him seem approachable and trustworthy. It made Yuichiro uncomfortable, but he tried to push the feeling aside for now. "Yeah, let's talk."

—

“Eh?” Tanjiro exclaimed. “So instead of eating humans, you eat other demons?! That’s amazing!”

“You really think so?” Muichiro asked, feeling self-conscious. Most people found his diet repulsive and tried to avoid talking about it. This was the first time a complete stranger had praised him for it instead.

The three of them were seated around Urokodaki’s table, Tanjiro and Yuichiro eating breakfast as they spoke. Urokodaki himself had gone into town, leaving them alone to talk amongst themselves.

“Of course! I think it’s amazing that you can fight against your instincts to protect humans. Not to mention, you can actually kill demons on your own? I thought that was impossible!” Tanjiro gushed, completely and utterly sincere in his words. “A demon-slaying demon; that’s so cool!”

“C-Cool…?” Muichiro repeated. His face was bright red but he couldn’t stop smiling. This boy with his father’s eyes made him feel all warm and fuzzy inside, like he was back home, before everything had changed.

Yuichiro, on the other hand, was glaring at the boy and looking sourer by the minute. Muichiro wasn’t sure why; Tanjiro had been nothing but kind to them. Maybe he was feeling irritable from a lack of sleep? But he only seemed to get really upset when Tanjiro was complimenting him…

“I think that’s enough about us for now,” Yuichiro said testily, taking Muichiro out of his thoughts. “What about you?”

“Me?” Tanjiro looked surprised, but his expression quickly turned downcast, as if recalling painful memories. “...My family and I lived as charcoal sellers up in the mountains. It was me, Nezuko, my mom, and our three little siblings. One day, I went down the mountain to sell charcoal like usual, but I couldn’t get back before nightfall so I stayed at a neighbor’s home. But when I came back…”

Tanjiro stopped, choking on his words. Muichiro placed his hand over the older boy’s, squeezing lightly to try and provide some comfort. He already knew where this story was going, anyway.

Tanjiro soon collected himself enough to continue. “Sorry… A-As I was saying, I came back in the morning to find everyone but Nezuko dead. A demon killed them, but I didn’t know that at the time. I took Nezuko to find a doctor, and that’s when she turned into a demon and attacked me.”

“I’m surprised you’re still alive,” Yuichiro commented. His anger was gone and he was now just listening closely and quietly.

“Honestly, now that I’ve had time to think about it, I am too. But at the time, even though I was so scared, I didn’t even think of hurting her. I just kept trying to get through to her, and somehow, it worked. That’s when Tomioka showed up.”

“Yeah, we know about that part. You foolishly tried to fight a Hashira, and when you failed, your sister protected you, right?” Tanjiro nodded. “So that's it? You’re saying you managed to get through to a feral, starving demon with only your words?”

When put like that, Muichiro had to agree it sounded too good to be true. He didn’t remember the time after his own transformation well, but he did know that he only became lucid again after satisfying his hunger by eating that other demon. Nezuko must have an unimaginably strong will.

“I know it’s hard to believe, but that’s what happened. Nezuko has been completely calm since then. Except for one time when a demon attacked us and she fought to protect me, she hasn’t hurt anyone.”

Yuichiro nodded. He seemed to be thinking hard about what he said. Muichiro turned to Tanjiro and asked, “What will you do now, Tanjiro?”

“Me?” Tanjiro blinked. A second later, a determined expression adorned his face. “I’m going to keep training to become a demon slayer. Then I’m going to find a way to turn Nezuko back into a human!”

Muichiro smiled. “Then we’re the same! Nii-san is going to make me human again one day too!”

“Hey, don’t put it all on me,” Yuichiro spoke up. “We’re both working hard to make you human again, remember?”

Muichiro chuckled softly. That’s right, it didn’t matter if one of them was a human or a demon. They were in this together.

Tanjiro watched them with awe. “A human and a demon, working together...! And you two are so young, but you’re already both Hashira, too! That's so cool!”

The cheer and kindness this boy exuded could hardly be described with words. If Nezuko was a sunny day, Tanjiro was the sun itself, radiating light and warmth. Muichiro practically glowed at his praise, and even Yuichiro looked away with a blush. “Don’t patronize us…”

“I’m not, though! You’re really incredible!” Tanjiro continued to insist with utmost sincerity. “How did you do it? Is there anything you can teach me?”

“You already have a cultivator, and we don’t have the time to be training anyone,” Yuichiro grumbled and stood up from the table. "We need to get going, anyway."

“Huh? But we still have at least a week before we go back to active duty,” Muichiro reminded him. Why was he suddenly so eager to leave when they’d only just gotten here?

The older twin crossed his arms and glared at the younger. “In case you forgot, we’re Hashira now. Off duty or not, we still have responsibilities.”

Muichiro frowned. He had a feeling Yuichiro was just looking for an excuse to leave, but he wasn’t about to confront him about it with Tanjiro right there. And his twin was right; they couldn’t neglect their other duties as Hashira. He gave the older boy an apologetic glance. “Nii-san is right, we can’t stay long. Sorry, Tanjiro.”

“Oh, okay,” Tanjiro looked disappointed, but he recovered quickly and smiled again. “I wouldn’t want to keep you from your duties anyway. But thank you for coming all this way to visit us!”

Yuichiro scowled and looked away, but he kept glancing back at Tanjiro. He seemed to be fighting with himself. “…Once that girl wakes up, send a message to the Master. I know you trust her, but she’s still a demon. The Master will want to see her himself, I’m sure.”

“Oh, um, okay…” Tanjiro looked nervous suddenly. “Um, this Master-”

“There’s no need to be scared! The Master is a kind and wonderful person! He’ll accept her for sure!” Muichiro assured him, clasping Tanjiro’s hands in his own. “So get stronger, and become a demon slayer! Nii-san and I will be rooting for you both!”

Tanjiro’s nervousness faded away. His words seemed to pump him up and fuel his determination even more. “Okay! I will! Thank you, Lord Tokito!”

“Just call us by our first names,” Yuichiro sighed. “It’ll get confusing otherwise.”

“Understood! Thank you, Yuichiro, Muichiro! Until we meet again, I’ll keep training!”

Muichiro really wanted to stay with this unfailingly kind and spirited boy longer, but it was time for them to go. He followed his big brother to the door and prepared to return to his basket. Before he did though, he caught a troubled look on his twin’s face.

“Yui? Are you okay?” he asked quietly. Yuichiro had been acting rather strangely. More on guard and irritable, and seeming to want to keep Tanjiro at an arm’s distance. He had been so interested in meeting him before. What changed?

Yuichiro sighed and dropped his tense expression for a more vulnerable one. “It’s hard to explain. But you noticed it, didn’t you? His eyes?”

Muichiro nodded. “He has the same eyes as Father.” An idea suddenly popped into his head. “Do you think we’re related?”

“What? No!” Yuichiro took a step back in his shock. “I mean, don’t you think Mother and Father would have told us if we had any living relatives?”

“I guess so, but it’s still possible, isn’t it?” Muichiro shrugged. “But, more than that, why does Tanjiro having Father’s eyes bother you?”

“I told you, it’s hard to explain. It just… brings back memories, that’s all.” Yuichiro mumbled the last part, but Muichiro heard it anyway. “I know it sounds dumb, but-”

“It doesn’t. It doesn’t sound dumb,” Muichiro wrapped his brother’s hand in his own and squeezed. “I get that it can be hard to put those feelings into words. But if you ever want to talk about it, I’m here for you.”

“…Yeah, I know.” Yuichiro smiled and squeezed his hand back. “Thanks, Mui.”

Muichiro grinned, and the two left Urokodaki’s home to head back to town. He wished the best for Tanjiro, and hoped that Nezuko would wake up soon.

—

It would be almost two years before they heard the fateful news, that the demon Nezuko Kamado had awoken at last.

Chapter Text

“Muichiro, cut her off! Don’t let her get away!”

Yuichiro jumped back as a swarm of moths swept through the spot where he’d just stood. His sword moved to cut through them, but more just took their place, nipping and biting at whatever they could reach. The demon commanding them was a Lower Moon - the new Lower Moon Four. It had been almost two years since they’d engaged one of the Twelve Moons, and Yuichiro would not let this chance slip by. This time, they would get the Lower Moon’s blood for Tamayo.

The demon turned to flee, only for a wall of white mist to block her path. Muichiro leapt out, mist sword in hand, and severed her head in one swing before hiding away again. Lower Four shrieked, and her body sprouted giant moth wings that flapped and kicked up a strong wind. The winds blasted the mist away, scattering it amongst the trees.

“Mist Breathing, Sixth Form: Lunar-Dispersing Mist!”

The Lower Moon caught and reattached her head, but the distraction had given Yuichiro time to dispatch the moths with his sixth form. He landed and lunged, swinging his sword twice and severing her wings, then launched a third strike towards her neck. His sword met flesh and sliced through with ease, and the demon’s head hit the ground for the final time.

Yuichiro breathed a sigh of relief, allowing himself to relax now that the battle was over. Though fighting the demon had been nothing compared to finding it. These new Lower Moons were cowards who ran away at the slightest glimpse of a Hashira, and tracking it down had taken weeks of investigation. Without Muichiro’s keen sense for detecting other demons, they might not have found it at all.

But now the Lower Moon was dead and the twins could collect their reward. Yuichiro took a syringe from his uniform’s pocket and threw it in the puddle of the demon’s blood, letting it draw it up automatically. He heard a meow, and watched as a cat wearing a satchel seemed to appear from thin air. The young slayer collected the syringe and placed it into the cat’s bag, after which it mewed and disappeared once again.

Yuichiro frowned. Who knew Tamayo had a demon cat, of all things? He hoped this was a unique case and there weren’t more demon animals running around. Demonized humans were bad enough.

Muichiro’s mist drifted up to him and partially reformed. The younger twin shook his head, looking a little dizzy.

“Are you okay?” Yuichiro asked.

“Yeah, just feeling a bit… scattered.” The mist was still drifting back to him as he pulled himself together.

Yuichiro cracked a wry grin. “Were you trying to be funny just now?”

“…Maybe. Did it work?”

“Mmm, B for effort.”

“Hey!”

Yuichiro started laughing. Muichiro pouted and crossed his arms, but then his gaze drifted, and his expression softened. “We need to check on the hostages.”

Yuichiro stopped as he watched his brother walk towards the humans they’d just saved. There were three of them, two men and a woman. One man was lying on the ground, face twisted in pain, while the others huddled around him. Muichiro sat next to them, and the two humans looked between each other nervously.

“Don’t be scared, he just wants to help,” Yuichiro assured them, coming to sit beside his brother.

Muichiro smiled gratefully and sniffed the air. He looked intently at the humans. “Those two aren’t injured.” He then looked down at the third human, and his eyes narrowed. “This one was poisoned, but it’s spreading slowly. He’ll need to be treated by Shinobu.”

“Alright,” Yuichiro nodded. He lifted up a finger to the sky, and Ginko descended to land on it. “Send a message to the Kakushi and the Butterfly Estate, tell them we have one civilian in need of treatment.”

“Of course!” Ginko squawked and took off.

He watched her go and turned to address the humans. “Help will be coming soon.”

“T-Thank you so much!” the woman said. Her relief was clear as day. “How can we ever repay you?”

Yuichiro looked away to hide his reddening face. “There’s nothing you need to repay us for. We’re only doing our jobs.”

Within the hour, the Kakushi arrived and took the survivors back towards the nearby town, leaving the twins on their own. The silent forest, devoid of the sounds of fighting, pressed in on them. Yuichiro fidgeted in place, looking around for signs of movement amongst the trees.

“Yui? Are you okay?” Muichiro asked.

“Y-Yeah!” he jumped and tried to recompose himself. “Yeah, I’m fine. Do you, uh, sense anything around here?”

Muichiro shook his head, his expression darkening. He knew what he was talking about. “No. I don’t feel him nearby.”

Yuichiro let out a relieved sigh. “Good. That’s good…”

Despite his words, he couldn’t help but worry. They hadn’t seen a single sign of the Upper Moon One, Kokushibo, since that night at their old home so long ago. It was objectively a good thing; despite all the twins’ training since then, he still didn’t believe they could match up against that demon. But the more time passed, the more anxious he became. It felt like he was dangling by a string, waiting for it to finally snap. Why hadn’t the Upper Moon showed himself? What was he planning? He had no idea, and that terrified him.

”Nii-san,” Muichiro’s hand gripped his own, pulling Yuichiro from his spiraling thoughts. He gave him a reassuring smile. “He’s not here. I know that. We’re safe here.”

“How do you know?”

“I just do.”

It wasn’t a good answer, but Yuichiro trusted his brother. If he said Kokushibo wasn’t nearby, then he wasn’t. He took a deep breath, scolding himself for his weakness. He was a Hashira. He couldn't allow himself to be scared of shadows in the dark.

Muichiro looked in the direction back towards town, and his smile dropped. “I hope that man will be okay.”

Yuichiro relished the change in subject. “I’m sure he’ll be fine. We found him so quickly because of you, after all.” He smiled proudly. “You did good.”

Muichiro giggled. “Y’know, you’ve gotten a lot nicer, Yui.”

“Eh? What are you talking about? I’ve always been nice.”

“Sure, whatever makes you feel better.”

“What’s that supposed to-”

“Emergency Hashira meeting! Emergency Hashira meeting!”

Yuichiro and Muichiro looked up as the Kasugai crow flew overhead; it wasn’t Ginko, but rather one of the Master’ messengers. An emergency meeting? What could have happened? For a moment, they feared that a Hashira had died, but that worry was dispelled as it continued.

“The demon Nezuko Kamado has awoken! As a demon who has never eaten a human, she is to be put on trial and tested! Report to the Demon Slayer Corps Headquarters by next nightfall to await the trial of Nezuko Kamado!”

Both twins froze. Yuichiro knew Muichiro was thinking the same thing he was. Nezuko Kamado, the demon they had found in a deep sleep almost two years ago, was awake? After all this time with no new information, Yuichiro had to admit that he’d started to consider her a lost cause. Why did she wake up now? And what about her brother, Tanjiro, who had been training to become a demon slayer?

Not only that, but the meeting was being held at night. With how busy they all were, Hashira meetings were only held at night when Muichiro’s presence was necessary. It was all the more important, then, that they get there fast.

“Come on, Muichiro, let’s go!”

Muichiro nodded and returned to his basket in a flurry of mist, and Yuichiro took off towards the Ubuyashiki Estate.

—

The hunt for Lower Moon Four had taken them a long distance away from headquarters. The twins reached the Estate by sunset to find the other Hashira already present in the courtyard. As he got closer, Yuichiro realized they weren’t quite the last ones to arrive; Sanemi wasn’t present either. He wondered if he was just late or waiting somewhere else, but for the sake of appearances, he didn’t voice his question aloud.

“Ah, Yuichiro, Muichiro, you’re finally here!” Shinobu called as he approached. Her voice caught the attention of a certain fiery haired man, who smiled broadly at their arrival.

“Yuichiro, my boy! It is good to see you safe; you’ve grown since I last saw you!” Kyojuro greeted.

“It’s only been a month since our last mission together,” Yuichiro reminded him.

“Nevertheless, I am glad to see you in good health!”

Yuichiro hummed and nodded in response. He didn’t say it out loud, but he was glad to see that Kyojuro was safe as well. He was glad that they were all safe and alive. He turned to Shinobu. “Our mission last night was pretty far away, but we came as soon as we could. Where’s the demon girl? And what about her brother?”

“I’m told that Tanjiro Kamado is with the Master,” Shinobu answered. “Now that we’re all here, the trial should begin shortly.”

Yuichiro tilted his head, looking around and counting everyone again. There were still only nine people, including himself and Muichiro. “What about Shinazugawa? I don’t see him around.”

“Shinazugawa was taken away shortly after he arrived. I would assume it’s related to the upcoming test.”

“That guy better not try anything stupid,” Yuichiro huffed.

“I agree. We can only hope he behaves himself, although that might be asking a little too much of him,” Shinobu smirked, and Yuichiro mirrored her expression. They briefly shared a laugh at the Wind Hashira’s expense. The sun finally dipped below the horizon as the Hashira idly chatted amongst themselves, and Muichiro bounced restlessly in his basket. Yuichiro wasted no time in setting it down and allowing him to pop out, upon which he was immediately wrapped in a big hug by Mitsuri.

Shortly after, two voices rang out. “The Master has arrived.”

The nine Hashira present moved into their usual positions as the Master walked out, guided by two of his daughters holding out lanterns for visibility. But alongside them was a boy, who Yuichiro recognized instantly. Despite the passing of time, the checkered green haori, hanafuda earrings, and scar on his forehead were unmistakable. Tanjiro Kamado looked nervous as he walked alongside the Master. His eyes landed on the twins and went wide, but he held back from saying anything.

“Good evening to you all, my beloved children,” the Master began. “It is not often we meet at this time; please forgive me for calling you away from your duties. But I assure you that this matter is of the utmost importance, so please, have patience.”

“It is no trouble at all, Master! We are honored to be here!” Kyojuro spoke up first in his usual booming tone. “May you continue to be in good health!”

“I thank you, Kyojuro.” The Master smiled and lowered his head. “Truly, this is a momentous occasion. For a second demon has appeared who has not eaten human flesh and blood. I feel the winds of change shifting.”

The two girls led the Master to his usual seat under the engawa. As he sat down, he nodded to Tanjiro, who moved forward. The boy stepped off the engawa and knelt before the Hashira, in the same spot that Yuichiro had once pleaded for Muichiro’s life two years ago.

“Y-Yuichiro, Muichiro…!” he breathed out, clearly anxious but happy to see them.

Muichiro grinned and waved. Yuichiro elbowed him to get him to stop, but he did give Tanjiro a nod of acknowledgement.

“As you may be aware, Tanjiro Kamado and his sister Nezuko Kamado were discovered by the Corps two years ago. According to the report by Giyuu Tomioka, Nezuko had just been turned into a demon, but fought to protect her brother instead of devouring him. Tanjiro and Nezuko were then taken into the care of Sakonji Urokodaki, a former Hashira and current cultivator. While Tanjiro trained to become a demon slayer, Nezuko fell into a deep sleep from which she has only recently awoken.”

The Master explained this for the benefit of the Hashira who weren’t familiar with the Kamado siblings. It was nothing Yuichiro didn’t know, but he listened intently anyway. He inadvertently made eye contact with the overwhelmed Tanjiro, and a chill ran down his spine. He had forgotten how much those familiar red eyes disturbed him.

“Tanjiro has passed Final Selection, and has expressed a desire to fight as a demon slayer and to have his sister fight alongside him,” the Master explained. “Therefore, we have decided that the best course of action is to test Nezuko’s ability to resist her demonic instincts. Our own Mist Hashira, Muichiro Tokito, passed this test when he first joined us, and so Nezuko will be given that same test as well.”

Silence fell as this information sank in. Yuichiro had expected something like this. It explained Shinazugawa’s absence.

“Is… Is this really necessary?” Tanjiro asked, fear and uncertainty lacing his tone. He looked imploringly at the Hashira. “It’s been two years, and Nezuko has never hurt a human. She never will, either! She’s not a threat to anyone!”

Yuichiro understood Tanjiro’s feelings. He really did. But now wasn’t the time to let emotions cloud his judgment.

“…Sorry, but it’s necessary.” Yuichiro spoke up. All eyes turned to him; there was an implicit agreement amongst the Hashira that his and his brother’s words carried the most weight here. “You understand, don’t you? Even if the Master and all of us were to accept your sister, the rest of the Corps would still see her as a dangerous demon. They must have solid proof that she will not attack a human.”

“But is this truly the only way?” Mitsuri asked, empathetic tears in her eyes. “I know it’s only fair, but it still seems cruel.”

Yuichiro was about to answer her when a familiar voice interrupted.

“Don’t waste your breath, Tokito. You said it yourself, there’s only one way this can be settled.”

Yuichiro’s head snapped towards the source of the voice. He grimaced at the sight of Sanemi, bearing new scars since he’d last seen him, and holding a wooden box in one hand. A wicked smile adorned his face. Yuichiro could sense the demon inside the box, as could Muichiro, who gasped, a sudden anxiety rolling off him. Yuichiro quickly took his hand to keep his twin from doing anything rash.

“Shinazugawa… Don’t you dare hurt her,” he warned the Wind Hashira. He still resented him for what he had put Muichiro through. “If you’re going to test her, your blood is more than enough.”

“Huh? What do you mean by that?” Tanjiro was looking at the box with obvious worry.

“What he means is that I’ll be the one to test the demon. If she passes, then she gets to live. If not...” Sanemi’s free hand gripped the hilt of his sword. He looked at the box with unveiled contempt. Tanjiro’s expression turned tense as he glared at the Hashira.

“Shinazugawa, please be a little bit more respectful,” Shinobu requested with a put upon smile. “Tanjiro has followed all our rules and come here willingly. There’s no need to rile him up.”

“Whatever. No one’s got any objections, right?” Shinazugawa scoffed and swept his gaze over all of them.

None of them did. Kyojuro and Tengen enthusiastically voiced their approval, Gyomei agreed even as tears ran down his face, and Mitsuri reluctantly accepted there was no other option. Obanai and Shinobu both stayed silent, simply observing the situation. Giyuu also chose not to speak, but that was normal Giyuu.

Muichiro looked like he wanted to protest, but he was already outvoted. “…Sorry, Tanjiro. Nii-san is right. This is the only way anyone will trust her.”

Yuichiro glared in Sanemi’s direction. “Hurry up and get it over with.” He really hoped Nezuko would pass and wipe that smug grin off the Wind Hashira’s face.

“Heh, sounds like we’ve got a consensus, then,” Sanemi chuckled. He roughly tossed the box onto the ground several feet away, and Yuichiro sighed inwardly; could he not act with a single shred of decency? Sanemi’s sword cut across his own arm, and immediately his blood began to drip down onto the stones at his feet.

“Come on out, demon! It’s time to eat!”

Muichiro covered his nose and mouth with his hands to block out the smell of marechi blood, a muffled growl escaping him. Yuichiro immediately shifted to sit closer to him, their bodies pressed together to distract him with Yuichiro’s own scent. It worked, to a degree. Muichiro quieted down, but he was still tense, slit pupils trained not on Sanemi, but on Nezuko’s box.

Said box had sat still, the demon inside seemingly not even reacting to the marechi blood. But that only angered Sanemi, who scowled and stomped closer with his sword gripped tight. He dug the blade into the tiny grooves of the box and ripped off the door separating its inhabitant from the outside world. A muffled grunt came from inside. Sanemi stepped back, bleeding arm held out as, very slowly, the demon stood up. The Hashira and Tanjiro watched with bated breaths.

It was indeed Nezuko Kamado, wearing the same pink kimono with a brown robe that the twins remembered, as well as the bamboo muzzle tied over her mouth. Her eyes, which they were seeing for the first time, were pink, slit like a cat’s, and glaring hungrily at the Wind Hashira. Yuichiro sat on alert. The Marechi blood was certainly affecting her, but the real test was if she could resist the temptation to attack in the face of said blood.

But seconds passed, and Nezuko refused to take Sanemi’s bait. She turned her head away defiantly, and for a moment, Yuichiro thought that that was it. Until Sanemi’s scowling face twisted into a dangerous grin. “Fine, you’ve got some restraint. How about if I do this?!”

In the blink of an eye, Sanemi lunged forward and slammed the blunt of his sword into Nezuko’s side. The demon girl couldn’t even react, screaming into her muzzle as she was thrown to the ground.

“Nezuko!” Tanjiro shouted in horror. Mitsuri gasped aloud and Muichiro snarled, only being held back from leaping at the Wind Hashira by Yuchiro’s hold on him. But that didn’t mean the older twin was any less furious.

“What the hell are you doing, Shinazugawa!?” he yelled. “She passed the test!”

“Not yet she hasn’t! You’ve gotta rile a demon up first to make them show their true colors!” Sanemi shouted manically. “Make them feel like they’re in danger, and then see what they do!”

He brought the sword down again, blade first. Nezuko barely managed to roll to the side in time as the blade stabbed into the ground. Her eyes were wide with fear, but she made no move to attack. She backed away like a frightened mouse.

Sanemi chuckled as he pulled his katana free and brandished it in the moonlight. “Don’t be shy, demon! You’re hungry, aren’t ya? Well, there’s food right here!”

“Stop it!” Tanjiro suddenly screamed, teary-eyed and furious, as he got to his feet and rushed at the Wind Hashira. Sanemi turned away from Nezuko and raised his sword as the unarmed boy drew close. He growled and lashed out with a horizontal slash.

His sword met Yuichiro’s katana; in one swift moment, he had thrown himself between them. The Mist Hashira pushed the blade away and stood protectively in front of a stunned Tanjiro. “That’s enough! What do you think you’re doing, attacking someone who’s unarmed?!”

Sanemi seemed surprised at first by his intervention, but it quickly wore off as murderous anger returned. He looked back at Nezuko, and saw Muichiro crouched in front of her, glowering at the Wind Hashira. Nezuko also looked Sanemi’s way, but she only stared intensely at his face, not once glancing at the blood staining his arm.

Yuichiro met his glare as he turned back. “This test is over, Shinazugawa.”

“…I see,” the Master’s voice shocked both Yuichiro and Sanemi back to the reality around them. The sickly man pulled away from his whispering daughter and looked out over the Hashira. “Sanemi, Yuichiro, Muichiro, please return to your places.”

The two Hashira turned away from each other; Yuichiro suddenly felt a deep shame for daring to have gotten into a fight in front of the Master. Muichiro reluctantly left Nezuko’s side to accompany his twin back to their spots, hands held tight, while Sanemi knelt down where he stood. Tanjiro looked around awkwardly, his anger extinguished and now at a loss for what to do, until Yuichiro motioned for him to kneel as well.

The Master smiled with satisfaction. “I believe we have our answer. I ask that you all accept Tanjiro and Nezuko into the Demon Slayer Corps.”

The other Hashira were stunned, but this wasn’t the first time this had happened, so they recovered quickly. One by one, they voiced their consents.

Yuichiro rolled his eyes. “As if you even have to ask. I knew she would pass.”

“Me too,” Muichiro nodded and smiled, but his grip on Yuichiro’s left hand was still tight. The older twin didn’t say anything, but he hoped he’d let go soon, before he lost circulation.

Sanemi said nothing, bowing before the Master with a scowl on his face. After a long silence, the Master continued. The discussion that followed was one that Yuichiro only half paid attention to. Something about the boy and his sister proving themselves by slaying a Lower Moon. He wasn’t ignoring the Master, but he couldn’t keep his attention off of Nezuko. Watching her fume silently in her box reminded him of Muichiro two years ago in her same position.

“One last thing,” the Master said, drawing his attention back to the present. “Sanemi.”

The Wind Hashira sat straight, his expression stiff and unreadable. “I understand your anger. However, your actions tonight were not within what we agreed on for the test. So, try not to antagonize our new recruits any further.”

It was essentially a slap on the wrist for blatant insubordination. But at the end of the day, the Demon Slayer Corps was understaffed and desperately needed Sanemi’s skills. And if what he had heard of his past was true, and the Wind Hashira had been forced to fight and kill his own mother turned demon, his anger was all the more understandable. To see not one, but two demons resist their instincts to kill when his mother couldn’t… Yuichiro would be beside himself with fury if he was in Sanemi’s place.

“Yes, sir,” Sanemi nodded, his voice flat to not let his anger spill out. The meeting drew to a close, and the Kakushi came to take Tanjiro and Nezuko away. Yuichiro knew Tanjiro was watching him, but he avoided looking his way.

The Hashira disbanded to fulfill their individual duties. Sanemi was the first to go, which was for the best, as Yuichiro would have certainly done something he’d regret if he stuck around. Or maybe Muichiro would have instead, as he still hadn’t released his death grip on his brother’s hand.

“Mui, let go. You’re hurting me,” he finally whispered, now that he was able to do so. Muichiro’s narrowed eyes shot open, and he hastily released his grip.

“Sorry!” Guilt was all over his face as he apologized.

Yuichiro shook his head. “Don’t worry about it. That bast- that jerk Shinazugawa really got to you, huh?”

Muichiro’s expression darkened again as he nodded. “He’s too cruel.”

Yuichiro had to agree. Even if he understood where the older Hashira was coming from, Shinazugawa let himself get carried away too easily. He could have really hurt Tanjiro if Yuichiro hadn’t intervened in time. And he upset Muichiro again, which was unforgiveable. He was considering what to say to make his brother feel better when he felt a tiny hand on his shoulder.

“My, that was quite the meeting, wasn’t it?” Shinobu said in her usual, overly sweet tone. “But I must say, you surprised me, Yuichiro. I didn’t expect you to get so angry on Tanjiro’s behalf.”

Yuichiro felt his cheeks heat up; he didn’t like that teasing tone she used. “It… it wasn’t for Tanjiro’s sake… Shinazugawa was just being unreasonable, that’s all.”

“Well, I don’t disagree there. However, what I came here to ask was if you two would like to come to the Butterfly Estate with me. Tanjiro and Nezuko will be staying there for the time being, and I think they’d both like to see you again after tonight.”

“Really?!” Muichiro’s eyes glowed even brighter than usual. He turned to his brother with a pleading look. “Can we, Nii-san? Please? Please?!”

Yuichiro fought not to show his own reservations. He had no problems with Nezuko, but Tanjiro… no, he knew he was being unfair. His problems with the boy were entirely his own. And he couldn’t bear to disappoint his brother, no matter how he felt. He forced a smile and nodded.

“Sure, we've got time. Let's go.”

With a cheer from his brother, the three Hashira departed for the Butterfly Estate.

—

“…Well? Are you gonna knock or just stand there?”

Muichiro didn’t answer. As they stood outside the Kamado siblings’ door, the younger twin was seized by a sudden nervousness. He wasn’t sure why. He’d been so excited coming over here. Tanjiro’s voice inside, talking to Nezuko, sounded as friendly as he remembered. But… he couldn’t knock on the doorframe to go inside.

Yuichiro uncrossed his arms, looking concerned now. “Hey, Muichiro…? Are you okay?”

Muichiro still didn’t respond. He stared at the door and his half-raised hand. What was wrong with him? Was he afraid? Afraid of what? If Tanjiro was as kind as he was, then surely Nezuko was as well, right?

But maybe that was the problem. Nezuko was kind enough and had a strong enough will to resist eating humans. He couldn’t smell a drop of blood on her; her heart and soul were clean.

But he wasn’t. He devoured demons and their corrupted blood. What if Nezuko could smell that on him? What if she didn’t like him because of it? It wasn’t something he’d ever thought about because this situation had never come up before.

But now that it had, he couldn’t stop fearing the worst.

Seeing that he wasn’t going to do it himself, Yuichiro grabbed his hand to reassure him, and then knocked on the frame with his other fist. Muichiro jumped and held his hand tighter for support as the voice on the other side paused. A second later, Tanjiro opened the door.

“Yuichiro! Muichiro! It’s good to see you again!” His earnest smile was as radiant as ever, quelling some of Muichiro’s worry like a soothing balm.

Yuichiro frowned, not saying anything, and Muichiro realized he would have to speak up. “Y-You too, Tanjiro! It’s been a long time!”

“It really has been, huh? But I’m so glad you came by! I wanted to properly introduce you two to Nezuko!” As he spoke, said girl peaked around behind him, but she was a lot smaller than before, about the size of a toddler. Her eyes went wide at the sight of them, and her gaze locked onto Muichiro, who stared back nervously.

Tanjiro stepped aside, his sister following, and Yuichiro pulled his twin into the room. He still couldn’t tear his gaze from Nezuko. Why was she so small? But just as he thought that, she suddenly grew taller, quickly growing back to her normal age. He noticed her box in the corner, and how small it actually was. Ah, so she shrank to fit inside, like him and his basket. He found himself focusing on the box to avoid meeting her gaze. It was quite well made, built out of a pretty wood and expertly carved. Maybe he could get his own basket-

The demon girl reached out to him abruptly. Too abruptly. Muichiro was already anxious, and being caught off guard sent his instincts screaming. He growled before he could stop himself, and the girl’s eyes went wide as she withdrew her hand. He heard Tanjiro draw in a sharp breath while Yuichiro squeezed his hand tighter. Immediately, intense shame flooded Muichiro’s heart, putting out the fire that spurred him.

He’d messed up. He’d shown he didn’t trust her, and now she wouldn’t trust him either.

“I… I’m sorry,” he apologized, bowing his head. “I didn’t mean to-”

He stopped as he felt a hand on top of his head. The hand lifted and then touched him again. She was… patting his head? He looked up. The girl’s mouth was covered by her muzzle, but her eyes were smiling at him.

What a strange girl.

Strange, but kind, just like her brother.

Slowly, his fear subsided. “I’m… I’m Muichiro,” he said softly. “It’s nice to meet you, Nezuko.”

Nezuko closed her eyes and gave a happy sounding “Hmmrph!”

Yuichiro scrutinized the girl. “What’s with the muzzle?”

“Ah, well…” Tanjiro rubbed the back of his head. “Tomioka gave it to her to help control her hunger, I think, but now I think she just finds it comfortable. And she can’t talk even if we take it off, so it’s not hurting her in any way.”

“Really? You can’t talk?” Muichiro asked the girl, tilting his head. “Why not?”

Nezuko opened her eyes and tilted her head as well. “Hrmm…” She sounded sad.

“You don’t know? That’s odd.”

“You understand her?” Yuichiro asked. Tanjiro looked surprised as well.

“Sort of… I think it’s more that I can pick up on her feelings easily…” Muichiro tried to explain. But even that was strange; he had only just met the girl. Was it just because they were both demons? “You’re quite odd, aren’t you?”

Nezuko hummed, her eyes looking distressed. Muichiro shook his head. “It’s not a bad thing. People consider me odd, too.”

“That reminds me, what’s Nezuko been eating now that she’s awake?” Yuichiro asked the girl’s brother.

“Well, um, that’s just it…” Tanjiro smiled awkwardly. “…She hasn’t.”

“What.” Yuichiro looked at him in disbelief, and Muichiro also turned his way.

“I mean, Nezuko’s been sleeping for the past two years. She’s only been awake for a couple weeks, but she hasn’t eaten anything in that time. I’ve asked her if she’s hungry, but she always denies it.”

“You’re kidding. Then how is she regaining energy?” Yuichiro continued to press.

“I’m not really sure, but… she does sleep a lot.” Tanjiro admitted. “Is that normal for demons?”

“Not really, no…” Muichiro muttered, turning back to face Nezuko. She really was a very odd demon. He stared at her, trying to decipher her secrets. Nezuko stared back.

He must have gotten lost in thought again, because at some point, Tanjiro spoke up, chasing away the fog in his head.

“So… Why don’t we go outside? It’s a beautiful night!”

—

The nighttime air was pleasantly warm, and the moon and stars shone clearly overhead. Muichiro and Nezuko stood in the courtyard, wooden swords in their hands. Muichiro was trying to teach her the basics of handling a sword, but the girl was not nearly so adept as the twins had been when they’d first started training. Nevertheless, she tried her best to position her body and swing the bokken in the way he demonstrated. Tanjiro shouted words of encouragement from where he and Yuichiro sat at the edge of the engawa, tea and mochi between them.

It was a beautiful, peaceful night.

Yuichiro wanted to punch his past self for agreeing to come here.

“You’re doing great, Nezuko! Move your foot just a little further back! Yeah, just like that!” Yuichiro groaned mentally and subtly put more space between them. He wished he could be with Muichiro instead, but he knew he was a terrible teacher and wouldn’t be of much help. So he had no choice but to sit beside Tanjiro and hope the older boy wouldn’t try to talk to him.

But alas, luck was rarely on his side. “Yuichiro?”

Tanjiro turned to look at him. Yuichiro balked and tried to look like he was listening while avoiding making eye contact. He stared past the boy, focusing on a random tree to the side of his head. “Yeah?”

“I wanted to thank you for standing up for me during the trial. You and Muichiro both, actually. It really means a lot to me.”

Yuichiro was finding it very difficult not to look at his face. “It does?”

Tanjiro nodded. “Yeah. And not just tonight, either. Sometimes when training got to be too much and I didn’t know what to do next, I thought about what you two said to me, and it helped me keep going.”

Yuichiro wasn’t sure what exactly he was talking about. That was almost two years ago; his memory of what he said wasn't the best. Regardless, he needed to stop this sentimentality before it became too much for him.

“I didn’t do it for you,” he muttered harshly. “Shinazugawa was going too far and needed to be reminded of his place; that’s all. It wasn’t out of the goodness of my heart or anything like that.”

“Hm… you say that, but…” Tanjiro sounded thoughtful. Yuichiro glanced over and saw him grin. “I don’t think you mean it. I can tell you’re a good person, Yuichiro. You don’t have to be ashamed of that.”

“Huh? Who said-”

“And besides, whatever you do for others comes around to help you, as well. So, I’ll definitely repay you for this!”

Yuichiro froze, his heart and protests catching in his throat. He suddenly couldn’t breathe. Couldn’t do anything but think of those words.

“Whatever you do for others comes around to help you, as well.”

His father had said that too. His father’s eyes, his father’s smile, and now his father’s words.

Who the hell are you?

Tanjiro frowned. “Yuichiro? Did I say something wrong?”

“No! No, it’s nothing!” Yuichiro shouted as he snapped back to reality. He was so loud that even Muichiro and Nezuko paused to look their way. Yuichiro quickly composed himself and said, more quietly, “It’s nothing, just forget it.”

Thankfully, Tanjiro took the hint and dropped it. Their siblings also went back to their training, though not very successfully, as Nezuko once more misjudged the strength of her swing and fell over. Muichiro laughed and helped her up. After thinking for a while, Tanjiro leaned back and relaxed. “Muichiro and Nezuko look like they’re having fun. I’m glad that she has someone who understands her.”

Yuichiro nodded. He was happy for his little brother as well. “…I’m glad too.”

Tanjiro smiled peacefully. “I hope the four of us can continue to be friends like this.”

Yuichiro looked at him in shock. Friends? He had never said anything about being friends! Muichiro was the one who made friends. Yuichiro did not, least of all with boys that reminded him far too much of his dead father.

And yet, he still couldn’t stop the warm feeling blossoming in his chest.

This boy is dangerous.

If Yuichiro had a choice, he’d leave now and never look at him again. But he knew, seeing the joy on Muichiro’s face, that he’d be seeing a lot more of Tanjiro.

Chapter Text

“Nii-san, do you think Tanjiro and Nezuko are back yet?”

Yuichiro let out the suffering sigh of someone who had heard the same question one too many times. “Don’t know, don’t care.”

He didn’t take his eyes off his breakfast simmering on the stove as he spoke. Muichiro giggled and draped his arms over Yuichiro’s shoulders, floating in half-mist form so he could rest his chin on his brother’s head.

“Yeah, you do! You’re always asking about Tanjiro whenever we stop by the Butterfly Estate between missions!”

Yuichiro’s face turned red, and not from the heat of the stove. “That’s just so I can know when to be on the lookout so he doesn’t spot me…”

Over a month had passed since the Kamado siblings officially joined the Demon Slayer Corps. In that time, the twins had hung out with Tanjiro and Nezuko whenever they could find time between missions. Well, it was mostly Muichiro who hung out with them, while Yuichiro awkwardly stayed back until Tanjiro inevitably approached him to drag him into their games. Then a couple weeks ago, they both disappeared without even a goodbye. Shinobu assured them they were okay, but didn’t disclose anything beyond that.

Muichiro huffed, a frown somehow audible in his voice. “Yui, do you dislike Tanjiro?”

“Yeah, I do.”

“But whenever we’re together, you never take your eyes off of him.”

“I know. That’s the problem.”

“Huh?” Muichiro tilted his head, confused.

Yuichiro sighed. He didn’t expect Muichiro to understand; his twin still looked back on their father’s memory fondly, and was enamored with Tanjiro as a result. But Yuichiro just couldn’t feel comfortable around a stranger who resembled him so strongly. The man who died a pointless death and left his two sons to fend for themselves… He hated being constantly reminded of him. And yet, Yuichiro found it so hard to just ignore Tanjiro. That kindness drew in a more childish and neglected part of himself, one that he tried so hard to bury but just kept surfacing whenever the older boy was nearby. It made him feel vulnerable, and he despised it.

Yuichiro shook his head and abruptly moved the pan from the stove. Some of the grease flung off and burned his hand, offering a small but welcome distraction. “Breakfast is ready.”

He walked past a confused Muichiro to their living room and set the table, laying out his own grilled salmon and rice alongside a plate of raw salmon for his brother. His twin hovered nearby, looking like he wanted to say something, but he stayed silent and regathered himself before joining Yuichiro at the table.

As the twins ate their breakfast, a flutter of wings and a caw announced their crow’s presence as she flew in through an opened window. Ginko landed on the table in front of Muichiro and craned her head towards him, clearly begging for attention. And Muichiro was more than happy to give it to her as he gently ran a claw down her back.

Yuichiro scoffed, “You spoil that thing.”

“So? She does so much to help us, so she deserves it,” Muichiro laughed. Ginko nodded in agreement, looking even more prideful than usual. “And besides, you don’t spoil her at all. That’s why she likes me better.”

Ginko nodded again, shooting Yuichiro a smug look that Muichiro missed as she cuddled up to him further. Yuichiro sighed. “Do you have a message for us, Ginko?”

Ginko glared at him, then hopped out of Muichiro’s hands to the center of the table. “New mission! Head to Shimizu Jima, a small island off the shore of Hyogo! You are to meet with Giyuu Tomioka and his tsugoku at the Port of Kobe and secure a ship to Shimizu Jima!”

As Ginko finished her instructions, both twins exchanged equally baffled glances. “Tomioka has a tsugoku? Since when?”

Muichiro put a hand to his chin in thought. “I wonder who they are? They must be really strong.”

Yuichiro scoffed and rolled his eyes. “Or really patient.”

“Maybe they’re both! I can’t wait to meet them!”

“Well, you’ll have to. Kobe Port is a few days of travel away from here. Though I’ve never heard of this island…” Yuichiro put a hand to his own chin, trying to recall if he’d ever read about their destination. But why send three Hashira? Could the demon be one of the Twelve Moons?

Muichiro smiled. “Don’t overthink it, Yui! Ginko can fill us in more along the way, right?” He addressed the crow, scratching her belly and drawing a pleased caw and a nod.

Yuichiro frowned, but his twin had a point. He might as well get more information before he started worrying. The two Mist Hashira wasted little time in finishing their food and preparing for the trip, before setting off less than an hour later.

As they traveled, Ginko told them more about their mission. Shimizu Jima was a small, underdeveloped island filled with lakes and marshes and a single village to its name. The rural and isolated nature of the island made it the perfect hunting spot for a hungry demon.

And indeed, for a long time now, terrified rumors had spread of a monster that lurked in those waters. Countless numbers of people had gone missing over the years, but within the last few months, the amount of disappearances had increased, with the recorded casualties being over fifty and the reality likely much higher. It wasn’t just islanders being targeted, but also ships and visitors from the mainland, hurting trade and travel and leaving the island almost completely isolated.

This monster had to be a demon, and a powerful one. Even the demon slayers sent to the island to investigate had all vanished without a trace. It seemed to thrive in the water; how fitting, then, to send the Water Hashira to kill it. The demon’s elusiveness was also the reason the twins were being sent; Muichiro’s demon senses would be their best chance of finding it quickly.

There was no time to waste; their duty as the Mist Hashira demanded they get there as soon as possible. So Yuichiro ran as fast as he could, in order to reach the island before the vile demon could strike again.

—

Upon reaching Kobe, Yuichiro wasted no time in heading for the docks. Even though it was early morning, the port was alive with activity. The salty sea air blew strongly and made a mess of his hair as the young Hashira walked past sailors, travelers, and other people going about their business. The crowds, wind, and loud noises all irritated him, but at least the sun was shining. If they got a ship to the island, they’d be able to get there without worry of the demon attacking them when they were most vulnerable.

“Do you see Tomioka?” Muichiro asked, quiet so no civilians would hear him. Yuichiro almost missed his voice himself.

“Not yet. This place is pretty big. It might take-”

“Hey, Yuichiro! Over here!”

Yuichiro stiffened as he heard a voice he did not want to hear right now. “Fuck.”

Muichiro gasped dramatically. “Nii-san!”

“Oh, be quiet,” he huffed. “I’m fourteen, I can say fuck.”

“So I can say it too, right?” His brother sounded so hopeful.

But Yuichiro was more than happy to stomp that hope into the dirt. “No, you can’t. Demons don’t age, so you’re still eleven.”

“Hey, that’s not fair!”

Yuichiro ignored his twin and reluctantly turned in the direction of the one shouting at him. Tanjiro waved wildly to catch his attention, and Yuichiro noticed Giyuu standing beside him, quietly munching on a rice ball and staring out across the open sea.

“Oh, don’t tell me…” Yuichiro grumbled as he approached them. “You’re Tomioka’s tsugoku?”

“I am!” Tanjiro nodded, eyes sparkling with excitement.

“Since when?”

“Well, not that long, honestly. About two weeks. Sensei asked me accompany him on a mission, and then he asked me to be his tsugoku afterwards.”

Yuichiro gave him a strange look. Sensei? He would never have thought of Tomioka as teacher material. His blank face and depressing appearance did little to evoke the image of such a respectable figure. Of course, he was still a Hashira, but Yuichiro had to wonder how good of an instructor he actually was.

“Really? That’s… very proactive of you, Tomioka.” Yuichiro looked to the Water Hashira with a quizzical glance.

Giyuu shrugged. “He’s skilled, and quick to learn. He’ll make a good Water Hashira, someday.”

“Thank you, Sensei! I’ll do my best!” Tanjiro smiled brightly. Yuichiro turned away, feeling uncomfortable again.

“Is that Tanjiro?” Muichiro asked excitedly. “Hi, Tanjiro!”

“Lower your voice, idiot!” Yuichiro hissed. The last thing he needed was for someone to overhear and then have to make up an excuse as to how he was absolutely not carrying a person in a basket.

“Yeah, it’s me,” Tanjiro leaned in close and spoke in a low voice, just loud enough for the demon to hear. “It’s good to see you again, Muichiro!”

“Is Nezuko here, too?”

“She is! But she’s sleeping right now. Sorry!”

“That’s fine, we don’t have time for small talk, anyway,” Yuichiro cut in. “Tomioka, did you find us a ship?”

“Not yet. There’s no ships traveling to our destination, and everyone I’ve asked so far has been too scared to take us near.”

“Really? Not even for payment?”

Giyuu shook his head. “I’ve tried. There have been too many accidents recently.”

“We shouldn’t get discouraged, though,” Tanjiro said. “I’m sure we can find someone willing to take us.”

Yuichiro sighed; he had hoped this part would be taken care of before he arrived. “Well, let’s get this over with, then.” He walked off towards the boats floating just off the docks, trusting the other two would follow. It was times like these that he most wished Muichiro could walk in the sun. He hated talking to people; his twin was always the more sociable one.

He looked around at the various boats. He doubted any of the bigger ones would change their plans to accommodate them, but maybe one of the smaller, dingier boats would be receptive - or desperate - enough to accept their bribes. Eventually, he spotted a small fishing boat attended to by a lone sailor, and braced himself inwardly before approaching the man.

“Excuse me,” he caught the man’s attention. The sailor took one look at his uniform and his eyes narrowed.

“You’re with those two swordsmen looking to get to Shimizu Jima, aren’t ya?” he scoffed. “Well you can forget it. No one that values their life is going near that cursed place.”

Yuichiro glanced at the boat again. He couldn’t say he knew much about boats, but compared to the ones surrounding it, this one looked rather run down.

“Come on, we’ll pay you. Whatever you’d make on a normal day, we’ll double that.”

“Coming home hungry’s better than not coming home at all.”

“We’re not going there for a vacation. We’re here to take care of the monster.”

“Like I’d buy that. A couple of kids like you, monster hunters?” The man rolled his eyes. “And even if you are, you’ll just get yourselves killed. The monster sinks entire ships in the dead of night. No signs of its victims, just the broken ships at the bottom of the sea. It’s a fool’s mission.”

Yuichiro sighed, already losing his patience. “Look, you said this monster comes out at night, right? But it’s morning now. We’ll pay you to take us there, and then you can head right back before it gets dark. We don’t need you to wait for us.”

But the man just shook his head and walked away. Yuichiro growled and turned around to look elsewhere, only to jump at finding Tanjiro standing right behind him.

“Don’t sneak up on me like that!” he hissed, trying to calm his racing heart.

“Sorry!” Tanjiro laughed and held his hands up in surrender. “Um, maybe I can try talking to him?”

Yuichiro scoffed. “Sure, knock yourself out.”

He watched Tanjiro walk up to the irritated man and strike up a conversation. Yuichiro stepped away, taking deep breaths of the sea air to calm himself and dispel the headache building up. He really hated talking to people.

“Are you okay?” He looked up to see Giyuu walking towards him. His expression was blank but his voice held concern.

“I’m fine,” Yuichiro shook his head. “Don’t worry about me. Anyway, I have questions for you. Why did you take Tanjiro as a tsugoku? Since when have you been the teaching type?”

“Well, I’m not, really… that’s why I sent him to train with Urokodaki first,” Giyuu explained slowly, thinking over his words carefully. “But now I think I can teach him what he needs to know to become a Hashira.”

“That’s the second time you’ve mentioned that. Are you planning on retiring?” Yuichiro asked sarcastically, but Giyuu didn’t respond. Yuichiro raised an eyebrow, but before he could ask again, Tanjiro returned.

“We’re all set! We’ll head out as soon as the boat is ready!”

“What?!” Yuichiro shouted. “How the hell did you convince him so easily?!”

“Well, I just explained the situation we were in and asked him nicely, and promised that we’d repay him for his troubles.”

“That’s the same thing I did!” Yuichiro yelled.

“Well, he did say ‘nicely’…” Giyuu muttered.

But Yuichiro heard and turned on him instantly. “Don’t you say anything! You couldn’t get us a boat, either! I bet Tanjiro never convinced anyone sooner because your stupid rat face drove them all away before he could even try!”

Giyuu had no response to that; if anything, he looked a little hurt as he looked down at the ground. Tanjiro chuckled awkwardly and stepped in between the two Hashira.

“Let’s just… get on the boat, okay?”

—

Shimizu Jima came into view by early afternoon. The three humans and two demons were dropped off quickly, and their guide turned around and left as soon as Giyuu gave him his payment.

“Where are the other boats?” Tanjiro asked as they disembarked.

“Most likely sunk by the demon to keep anyone from leaving,” Yuichiro guessed. Indeed, there were no other boats at the tiny dock, so they were effectively stranded until they killed the demon and could send a message to the Master to retrieve them. It was a good thing that Ginko and Tanjiro’s crow had accompanied them over.

The walk to the village of Shimizu was short, quiet, and wet. It had clearly rained the night before, the ground soaked and muddy as they made their way through. The sun overhead seemed to do little to dry the ground. The humidity was already making Yuichiro’s hair and loose-hanging uniform stick to his skin. He regretted not tying his hair up for this mission.

But soon the village was before them. Yuichiro had been expecting a rural town of mostly vegetation and farmland, and for the most part, that was what it was. But small streams ran all throughout the village, and there was a startling lack of people outside for this time of day. Most of the people they could see out were farmers tending to their fields; the village itself seemed quite empty.

“This place feels strange,” Tanjiro said out of nowhere. Yuichiro turned to him and saw the older boy was frowning. “There’s all this water and nature, but the village itself… It feels sad. There’s a heavy cloud hanging over this place.”

Yuichiro felt that too. An unnervingly quiet air, as if they were standing in a graveyard and not the island’s main settlement. “We should look for an inn. See if there’s anyone who can tell us more about what’s been going on here.”

“Up ahead there,” Giyuu pointed forward, leading the two boys as they walked. A larger, two-story building stood out from the smaller buildings, a banner marking it as the place they were looking for.

Giyuu opened the doors to the ryokan, and as the boys followed him in, Yuichiro immediately picked up a tense atmosphere. All eyes turned to them, shocked and wary. It became apparent that this island had not seen new visitors in quite a while.

Giyuu paid them no mind as he walked through the foyer and up to the reception desk. Yuichiro followed his lead, hating the feeling of so many questioning, suspicious gazes on his person. Giyuu was already speaking to the woman at the desk as he caught up.

“One room for tonight, please.”

“O-Of course,” the poor girl looked quite nervous. “T-That’ll be fifty yen…”

“Thank you. What can you tell me about the recent disappearances on this island?”

Straight to the point! Yuichiro saw why Tanjiro was here; besides being Giyuu’s tsugoku, he was the only human present with any social graces.

“Um, I-I don’t know much, just what everyone else does. The disappearances aren’t new; they’ve been going on since I was a young girl, about twenty years. But they suddenly got more frequent within the last few months. And there have been those attacks on the ships coming to and from the island. All these people here are people who were stranded when the ships were sunk.”

“Excuse me, miss,” Tanjiro spoke up. “But how can you be sure that the attacks now and the disappearances from long ago are related?”

“It always happens the same way. People go missing near large bodies of water. There’s a rumor that a water monster that lives in Shimizu Lake is responsible.”

“And why is a lake monster attacking ships on the ocean?” Yuichiro asked.

“I don’t know, but why else would all those people just vanish without a trace? It must be the monster!”

“I see. No more questions. Thank you for your help.” Giyuu said with a nod. The girl led them to their room, and Yuichiro breathed a sigh of relief to finally escape the wary eyes following them. Once they were alone, the two younger demon slayers relaxed and set down their respective box and basket.

Yuichiro tapped the basket and Muichiro lifted the lid, but Nezuko stayed where she was, presumably still asleep. The older twin sighed and sat on the floor. “Well that didn’t tell us much.”

“We can assume a few things, though,” Giyuu thought aloud. “For one, the demon’s home seems to be in a lake near here.”

“That’s right!” Tanjiro held up a piece of paper. “I picked up this brochure, and it says Shimizu Lake is the largest and deepest lake on this island, located northeast of here! A big lake like that would make a good hiding spot for a demon.”

Giyuu nodded. “And second, we can assume that the demon’s powers are water-based.”

“That much was obvious,” Yuichiro rolled his eyes. “But we don’t know if it controls water or just lurks in it.”

Muichiro looked thoughtful. “If this demon has been hunting humans for twenty years, then it probably has a Blood Demon Art by now. I think we can assume it can control water in some way.”

“And this island is literally covered in water. That’s not a good position for us.” Yuichiro frowned. There was no denying they were fighting this demon on its home turf. It was bound to have some tricks for demon slayers who came looking.

Muichiro noticed his unease. “Don’t worry, Nii-san. With all five of us, we’re sure to find the demon. And whatever it throws at us, I know we can handle it.”

Yuichiro nodded. That’s right; their group consisted of three Hashira, a demon, and a tsugoku who he admittedly hadn’t seen fight, but had to be decent if Tomioka was training him. If this demon was anything less than an Upper Moon, it wouldn’t stand a chance. But if it was an Upper Moon…

“Muichiro, did you sense anything on the way here?” Yuichiro asked. “Anything that could clue us in on this demon’s strength?”

Muichiro shook his head. “There’s… a slight feeling. But it’s all over the place. I can’t detect it clearly.”

Yuichiro nodded. They had no choice but to go in mostly blind then. They waited until night fell and then left the inn. If the village was empty during the day, then it was absolutely deserted at night. Not a single person was brave enough to venture out, leaving the group of slayers to move freely.

They quickly traveled to the edge of the village where it was safe for Muichiro and Nezuko, who had finally woken up, to show themselves.

“Do you sense anything now?” Yuichiro asked his brother, who only shook his head again after a moment of concentration.

“I don’t smell the demon either,” Tanjiro added, sounding disappointed.

Giyuu looked around, then turned to the younger slayers. “It might be better for us to split into two groups. One group can stay within the village in case the demon attacks, while the other can search around Shimizu Lake.”

Yuichiro nodded; that made sense to him. They couldn’t search the whole island, so it was better they stay near the village where the demon would hunt to prevent any more casualties. “Fine. Muichiro, we’ll-”

“Wait!” Muichiro spoke up suddenly. He looked at the other demon in the group with a smile. “I want to go with Nezuko!”

“Huh?! Why do you-” Yuichiro didn’t get the chance to finish before Muichiro continued.

“It makes sense, doesn’t it? If the demon gets into the village, Nezuko and I will detect it the fastest! And if it’s at the lake instead, then Nii-san, Tomioka, and Tanjiro all together should be enough to fight it, right?”

“Yeah, that does make sense!” Tanjiro enthusiastically agreed. “I should be able to smell the demon if it’s close by, too, so we’ll have someone who can track the demon in both groups!”

Yuichiro shot them both an incredulous look. “Wait, hold on! Mui, you… you don’t want to pair with me?”

He couldn’t keep the hurt out of his voice. He probably sounded childish, but right now he didn’t care. Why was his twin choosing to go with someone else over him? But Muichiro shook his head and gave what was probably meant to be a reassuring smile to his big brother.

“It’s not that, I just think we’ll be more effective this way. Nezuko and I will defend the village while you guys hunt down the demon,” he explained. “And besides, this way, you can spend time with Tanjiro!”

“I don’t want to spend time with Tanjiro!”

“Huh? You don’t?” Now it was Tanjiro’s turn to look hurt. And seeing those red eyes look so wounded only stirred Yuichiro into a further panic. It was like seeing his father cry, something that felt completely wrong and unnatural to the young, childish part of himself.

“Wait, no, that’s not what I meant!” he backpedaled frantically. That was a lie, it was absolutely what he meant, but he would be mortified if Tanjiro actually started crying over it.

“There’s no time to argue about this,” Giyuu interrupted. “We need to move before the demon does. Those two will stay to protect the village while the rest of us pursue the demon at its home. Tokito, Tanjiro, follow me.”

He didn't give them a chance to respond before running off. Tanjiro recomposed himself quickly, giving an enthusiastic "Yes, Sensei!" as he chased after the Water Hashira. Yuichiro was still torn, until he found himself wrapped in a tight hug courtesy of his twin.

“Don’t worry, Yui! It’ll be fine!” he assured him. “If the demon shows itself here, I’ll send Ginko to find you, okay?”

“…You’d better,” Yuichiro hugged him back. After a few moments, he reluctantly let go and ran off in the direction Giyuu and Tanjiro had gone. He caught up quickly; Tanjiro wasn’t anywhere near as fast as him, and Giyuu had slowed down to keep pace with his tsugoku.

The lake they were heading towards wasn’t far from the village; it took them only minutes to reach it. But when they arrived, all that greeted them was a serene landscape, waters calm and reflecting the clear sky and moon above. Still, something felt off.

Tanjiro suddenly let out a soft retching sound, and Yuichiro looked to see him covering his mouth and nose, his eyes narrowed as though smelling something awful. “The smell of blood… is really strong here! This has to be where the demon lives!”

Yuichiro looked around, but his own senses couldn’t pick up anything beyond a general feeling of unease crawling on his skin. He couldn't sense the demon, but it was a large lake; who knew where it could be lurking?

“You two stay here and keep watch. I’ll scout around,” Giyuu said abruptly, and before either of them could say anything, he walked off into the trees.

“U-Um, yes, Sensei!” Tanjiro shouted after him, surprised by his swift departure. Yuichiro rolled his eyes.

“Hmph, some sensei. I’m surprised you’ve learned anything from that guy.”

Tanjiro laughed awkwardly. “Well, I know Tomioka-sensei can be… hard to communicate with-” Yuichiro scoffed and he quickly continued. “-but he is teaching me a lot! I’m learning Total Concentration Constant because of him!”

“Seriously? I learned that less than two months after I started training.” Yuichiro grumbled. “Even Muichiro only took four months to figure it out, and that’s only because he had to work around his demon regeneration hindering him. If he was human, I’m sure he would have figured it out even faster than me.”

“You really have a lot of respect for your brother, don’t you?” Tanjiro observed, ignoring the insult towards his skills.

Yuichiro huffed and turned his back to him. “Of course I do; Muichiro is incredible. He learned Mist Breathing in less than a week, and created a Blood Demon Art to kill demons. He's strong and reliable, and does whatever he can to protect others. I’d trust him to watch my back no matter what. More than I’d trust you, anyway.”

He knew that was low and unnecessary, but just being around Tanjiro right now was pissing him off, and Muichiro wasn’t around to calm his temper. Damn Tomioka for leaving them alone.

But Tanjiro didn’t seem bothered by his bitter words. Instead, he asked, “Yuichiro, are you upset because Muichiro chose to partner with Nezuko instead of you?”

Yuichiro spun around hard enough to give himself whiplash. “What?! No I’m not! I…” he trailed off, already knowing he wasn’t going to convince anyone. “…So what if I am?”

“You don’t need to be ashamed. I know you two are really close. It’s perfectly normal to feel jealous.”

“I’m not jealous…” Yuichiro tried to deny, but even he knew that was a lie. “…Why would he choose her? Do you think he's tired of me?!”

But before he could catastrophize further, Tanjiro shook his head. “I don’t think it’s like that. I think he’s just really excited to have a friend who's also a demon. Nezuko feels the same way, you know? Ever since he showed her how to fold origami, she’s been practicing every day to get better. It’s just a part of making new friends.”

Yuichiro nodded, trying to assure himself. Yeah, he was overthinking it. Muichiro was just happy to have a friend who was like him. But that didn’t make him feel any better. Not having his twin at his side made him feel on edge. And was a mission really the best time for him to want to bond with his new friend?

“…I don’t like this. What if the demon attacks the village? If I’m not there to protect him-”

“You should have more faith in your brother,” Tanjiro interrupted him. “He’s a Hashira too, right? I’m sure he can handle himself. And he has Nezuko with him; she’ll keep him safe.”

“Don’t be ridiculous. If anything, Muichiro will be the one keeping her safe.” Yuichiro crossed his arms. “And I do have faith in him. It’s just…”

Tanjiro nodded, still smiling that irritatingly warm smile. “I understand. He’s your little brother. You can’t help but worry.”

Yuichiro growled and turned away. He hated how easily Tanjiro could read him. “Enough talking. We have a mission to complete. We’ll circle the lake; keep your senses open and be ready for anything.”

Tanjiro nodded, and the two split up. Unseen by either, a ripple spread across the still surface of the lake.

—

Muichiro and Nezuko walked quietly through the empty village. Both were on guard, senses alert for any sign of the hostile demon, but besides the vague feeling all around them, nothing stood out. It seemed that, at least for now, the demon was nowhere near.

Muichiro glanced down at a small spring, checking his reflection in the water. A mirror of his brother stared back, albeit without his brother’s usual glare. But his eyes were that of a human, innocent and approachable. Good. There was still a chance someone would be out at this hour, and he didn’t want to frighten them.

Nezuko didn’t have to hide anything about herself; she passed as human easily enough even in her normal form. The muzzle was still a bit strange, but he was sure they could explain that away if needed.

“Hrrrmmm…” Nezuko hummed against said muzzle, looking at him with worry.

“You don’t have to worry, Nezuko! Tanjiro will be fine! He has Tomioka and Nii-san with him, after all!”

“Hmmph?”

“Huh, what about Nii-san?” But he realized what she meant almost as soon as he said that. “Oh, right! He’ll… he’ll be okay too…”

He could have sounded a lot more convincing, and Nezuko must have thought the same. She tilted her head to the side and muttered vaguely.

“No, it’s not that! I love spending time with Nii-san! It’s just… he should have more friends, you know? If I’m not around, he should have people he can rely on.”

Muichiro knew Yuichiro would protest that. He knew he would say he didn’t need anyone else as long as he had his little brother. He might even claim that he did have friends, like Kyojuro or Shinobu. But wouldn’t it be better if he could have friends closer to his age? Muichiro certainly thought so. And he knew Yui liked Tanjiro, even if he couldn't quite understand why his brother denied it so strongly.

“Mmmrrr…”

Muichiro’s smile slipped. “Yeah… I know. He must be feeling hurt. But I’m sure he’ll understand. He’s really smart, you know?”

Nezuko nodded, and Muichiro felt a little more at ease. That’s right, Yuichiro would surely understand and forgive him for this. And if not… well, he’d just have to make it up to him later.

As they continued walking, Muichiro quietly observed their surroundings. It was a beautiful place, tainted by an air of fear and blood. He imagined a more bustling village, full of people laughing and living their lives without worry of the night, and he felt fire run through his veins.

“It’s pretty here, huh, Nezuko?” Muichiro spoke up. “I bet this place used to be filled with people. If it wasn’t for that demon…!”

Muichiro truly hated demons. All creatures needed to eat, but demons killed in such excess of what was needed to survive. The Corps considered Muichiro unique for his relative lack of appetite, but the truth was that most demons were just gluttons, craving power above all else. This one was the same; to isolate an entire island as its feeding grounds was not necessary. This was not a predator. This was a cruel, calculating monster.

Nezuko’s hand on his arm shook him from his thoughts. He looked to see the demon girl giving him a concerned expression. She pointed up at her eyes and then at his reflection in the stream, and Muichiro realized he was letting his disguise slip. He blinked and reopened his eyes, the eerie glow gone.

“…I’m okay. Thank you,” he said quietly, trying to reassure her with a smile. Nezuko hummed, then ran ahead to a larger stream beneath a bridge. She knelt down and grabbed something, then ran back. In her hands was a lotus flower, its petals full and pink.

“Hrrrm!”

Muichiro’s smile turned more genuine. “Yeah, it is pretty. Once the demon is dead, I’m sure the people here will recover too. So let’s do our best to make that happen, okay?”

Nezuko cheered and followed him as they resumed their patrol. But no matter how many times they circled the village, the feel of the demon never grew any stronger. Hours passed, and Muichiro was growing agitated. Yuichiro would have sent a message by now if they had killed the demon, so maybe it wasn’t at the village or the lake? But searching the entire island would be inefficient, to say the least. He would just have to trust that the demon would show itself to hunt eventually. But he was getting antsy from the anticipation and resulting nothing. He was already missing his brother, no matter how many times he reminded himself that this was his choice in the first place.

More hours passed, and eventually morning drew near. Soon the sun would start to rise, and they would have to stop their search. Muichiro let out a frustrated sigh; what a waste of a night. He hoped Yuichiro’s group had found something to make up for it.

“Hey, Nezuko-”

“Who’s there?!”

He froze, an unfamiliar voice drawing his attention. Both demons looked up to see a human girl a fair distance away. She looked young, about their age, with brown hair and eyes. She gripped a pitchfork tightly in her hands, her expression fearful, and Muichiro realized she couldn’t see them clearly in the dark.

He held up his hands to show he was unarmed and smiled, hoping his fangs weren’t showing. “Don’t be scared! We won’t hurt you!”

The girl slowly drew closer, taking in their appearances. Upon seeing that they were - supposedly - human, she relaxed a little, but kept the pitchfork pointed at them. It was clearly just a farm tool, old and rusted from the humidity, and wouldn’t protect her from anything. What was she doing out here?

“I’m Muichiro, and this is Nezuko,” he introduced himself and his companion, who waved her hand in a friendly greeting. “What’s your name?”

“…Hina,” the girl said timidly. Her gaze hardened and she lifted the pitchfork higher. “I don’t recognize you two. What are you doing here?”

“We’re here to protect this place from the monster,” Muichiro answered truthfully. Hina’s eyes went wide, and he continued before she could speak. “What are you doing out here? It’s not safe at night.”

Hina suddenly looked guilty. She pulled the pitchfork away and looked over her shoulder, towards what seemed to be a stable. “I… I know I’m not supposed to be out after dark. But someone has to take care of the horses, right? Kimi just had her first foal; I can’t leave her now!”

“That’s very kind of you,” Muichiro smiled. A part of him wanted to see the little foal himself, but the more responsible side of him won out. “But it’s too dangerous to be out now. Please, go back inside.”

His words seemed to only upset the girl. Hina scowled and walked a few feet away before sitting down in front of a nearby pond. Panic briefly filled Muichiro before reason set in. This was okay; even if the demon struck from the water, he and Nezuko were right here. They could keep this girl safe.

He followed and, when she didn’t chase him off, sat down beside her, Nezuko following suit on his other side. “Is something wrong?” He mentally facepalmed as soon as the thoughtless question was out of his mouth.

But Hina didn’t scold him or anything. She just looked miserably at the water. “Papa was a fisherman. He was on one of the boats that the monster sank. It’s just me and Mama and the animals now.”

“…I’m sorry…” Muichiro considered reaching for her hand like he always did when his big brother was upset, but thought better of it. They were practically strangers, and his touch likely wouldn’t be welcome.

“Why? You didn’t do anything, right?”

“Huh? Well, no, but…” Muichiro trailed off. Was he feeling guilty for not stopping something that had happened long before he’d even heard of this place? Or just guilty for asking the question and forcing this grieving girl to speak?

“Hrrmm! Hmmmmph!” Nezuko cut in, saving him from having to answer that. Hina looked at her strangely, an eyebrow raised.

“What’s… with the muzzle?” she hesitantly asked.

“It, uh, helps her feel more comfortable,” Muichiro explained lamely. Still, it wasn’t a lie, per say… “But, she says she’s sorry for your loss, and that we’ll do everything we can to stop the monster that did this.”

“You understood that?” Hina asked, her confusion and skepticism overpowering her previous sadness.

“Um, sort of...” Truthfully, he had just picked up on her reassuring but determined tone and expression and filled in the rest of the blanks with his own sentiments. But that was hard to explain, and would no doubt leave the human feeling even more confused.

“Are you really going to beat the monster?” Hina asked suddenly. “No one’s even seen it, let alone tried to beat it. What makes you think you can?”

“It’ll be okay. I know we don’t look like it, but Nezuko and I are professionals!” He flashed Hina an encouraging smile. “If the monster attacks this village, we’ll definitely defeat it!”

“Mmrph!” Nezuko agreed.

On the far side of the pond, the water rippled and shifted. A single yellow light shone beneath the surface, silently watching the three children. The light glowed brighter with gleeful anticipation.

“Mu…i…chi…ro…!”

--

Yuichiro eventually met back up with Tanjiro after hours of fruitless patrolling. Tomioka returned empty-handed as well, confirming the demon was nowhere to be found nearby.

“Do you think we were wrong?” Tanjiro asked. “Or maybe the demon knows we’re here and plans to just hide until we leave?”

Yuichiro grimaced. The possibility was certainly there. They hadn’t heard anything from Ginko to indicate that the demon appeared at the village, either. But if it came to that, then they would just have to come up with a plan for the next night. “Just stay alert. There’s still time until morning.”

He kept an eye on the older but less experienced boy as he walked away, and it was then that he noticed it: a tendril of water sneaking out of the lake and wrapping around Tanjiro’s ankle. Yuichiro turned, already pulling his sword from its sheath. “Tanjiro-!”

The tendril tightened and pulled, dragging him off his feet. Tanjiro yelled in shock and dropped his sword as he was forcefully pulled down into the lake.

“Damn it!” Yuichiro moved to go after him, only to stop as Giyuu beat him to it, sword drawn as he dove into the water after his tsugoku. For a second, Yuichiro was left alone on the shore, but only for a second as the surface of the water broke again.

He stared in horror as three demons emerged from the water, dragging themselves ashore. They lurched and stumbled erratically, like mishandled puppets, an image only reinforced by the watery strings connecting their backs to the lake. Their grotesque bodies were bloated like drowned corpses, but the light in their eyes and their twisted, agonized faces showed that they were still very much alive.

With a unified roar, the three demons charged straight for the Mist Hashira.

Chapter Text

The demons lunged for Yuichiro all at once, and it was a simple matter for him to dunk under and dart past them. But what was going on? There had to be half an hour left until sunrise at best! Why was the demon choosing to attack now?

Despite there being three enemies, the water tendrils attached to them made it clear that a single demon was manipulating the others. Yuichiro’s sword sliced through the tendrils, but they reattached as soon as his sword swung through. So cutting their strings wasn’t an option. He jumped back to avoid another swing and aimed at the neck. Puppet or not, it was still a demon. But as he cut through the neck and the head rolled to the ground, the body kept moving. It slashed at him again, narrowingly missing his haori sleeve as he dodged. Something then burst out of the demon’s neck: a bubble of water in the vague shape of a head, holding a brain inside.

“What the hell?!” Yuichiro hissed and jumped back to put more distance between himself and the puppet demons. Was that the puppet’s brain? Is that why it didn’t die when he cut its head? The demon responsible for this was truly sick.

“Mist Breathing, Sixth Form: Lunar-Dispersing Mist!”

As the demon lunged for him again, Yuichiro leapt over it and swung his sword multiple times. The demon’s arms, chest, and most importantly, its exposed brain, all fell apart and turned to ash. So the brain was the weakness. Yuichiro took a low stance and readied his sword again.

“Mist Breathing, Fifth Form: Sea of Clouds and Haze!”

In an instant, he shot forward and cut through the remaining two puppets before they could lash out at him. He slid to a halt past them, and watched as both demons fell to pieces. One started crumbling, but the other was still twitching as the water tendrils invading its body pulled its parts back together. Yuichiro wasted no time in slashing through the now revealed brain and putting an end to its threat.

A loud splash came from his right, and Yuichiro spun with his blade ready. But to his relief, it was only Giyuu holding onto a coughing Tanjiro. He crawled ashore quickly, and Yuichiro rushed over, stopping briefly to pick up the tsugoku's lost sword.

“What happened?” Yuichiro asked, crouching beside them. Tanjiro was still hacking up lake water, so Giyuu was forced to answer instead.

“There’s demons in the lake. A lot of them.”

“Yeah, I’m aware.”

“Does this mean the attacks were caused by a group of demons working together?” Tanjiro asked once he recovered enough to speak.

Yuichiro shook his head. “No, there’s one demon controlling the others."

The surface of the lake broke again, and more demons leapt out to surround the three slayers, who stood up with their swords drawn and ready. Yuichiro called out, “You have to cut the brains! The demon will try to move them, so cut through multiple spots at once!”

Giyuu and Tanjiro nodded, acknowledging his warning. Then the three broke apart to tackle their foes. It was soon apparent that these were weak demons; the two Hashira cut through their opponents with ease, and even Tanjiro was able to keep up against two or even three at once. Yuichiro couldn’t help but feel that these puppet demons weren’t meant to kill them; rather, they were only meant to slow them down and distract them. But from what?

“Water Breathing-!” Tanjiro jumped as a puppet suddenly charged him with unexpected speed. Yuichiro turned to aid him, but the older boy was already executing another technique as he leapt above the demon’s downward strike.

“Water Breathing, Eighth Form: Waterfall Basin!”

At the same time the demon’s fists struck the ground, Tanjiro’s sword came down in a downward swing that sliced through its head. He and the demon landed heavily, but suddenly the ground started to cave in beneath them. Yuichiro leapt forward and grabbed Tanjiro by the waist, throwing them both to safety just before the ground collapsed, the puppet demon falling with it.

Both boys looked with surprise at the large hole left behind. The sounds of fighting ceased and Giyuu approached, stopping to look down into the pit. “It’s dark, but I can hear water flowing.”

“Is it some sort of underground river?” Yuichiro asked, trying to look without getting too close to the edge in case it crumbled further.

Tanjiro sniffed the air and covered his nose again, grimacing. “The demon’s smell is really strong here! I think this river is going towards the village, too!”

“You think so?” Yuichiro asked. So not only could the demon travel through the waters above ground, but under it as well. “Do you think this tunnel is natural?”

“I doubt it. It’s more likely that the demon dug this tunnel to get around more easily. In which case, this underground tunnel system could travel beneath the whole island.” Giyuu took a stone from the lakeshore and tossed it into the pit. A couple seconds later, they heard a plop as it landed in the water. Low growls came from within.

Yuichiro narrowed his eyes. “More puppets.” How many were there? How had the demon gotten them in the first place? A demon that violated the bodies of other demons just as much as it did humans; just what kind of monster were they dealing with?

Giyuu nodded. “We need to head back to the village. I have a bad feeling about this.”

Yuichiro was about to agree, when he heard the flapping of wings and a caw overhead. Ginko.

Muichiro and Nezuko had found the demon.

—

The peace of the night was broken by the sound of water splashing loudly. The three children looked up, eyes going wide at the sight of two large figures emerging from the pond.

“Demons!” Muichiro hissed. But something seemed off. The demons’ presences felt weak, they moved slowly and awkwardly, and their faces twisted in pain. But then one of them roared and lunged towards Hina. Muichiro pushed the stunned girl behind him, but before he could fight back, Nezuko was suddenly between them. She lashed out with a spinning kick, and the impact of her foot ripped the demon’s head from its body.

Hina finally recovered enough to scream. Muichiro bit back a growl and forced the girl to her feet. “Go, run! We’ll take care of the monsters!”

The human almost lost her balance from how much she was shaking, but thankfully, she steadied herself and did what he said. Muichiro tried to watch her until she was out of sight, but then Nezuko cried out, and he narrowly turned in time to dodge a blow that would have taken his own head off. The second demon attacked again, but Muichiro’s body burst into mist and flowed past it. He noticed water tendrils extending from a hole in the demon’s back to the pond, and suddenly the strange feeling he had made sense. These weak demons were just pawns of something stronger.

He then noticed Nezuko struggling with the first demon. She pushed against it as it tried to grapple her to the ground, still headless but somehow moving the same despite that. Its claws dug into her wrists and drew blood.

Muichiro moved in to help her, his mist surrounding the demon’s head and chest. The puppet’s skin melted, but it didn’t stop its assault. With a shout, Nezuko finally managed to tear her right hand away, taking her opponent’s hand with it, and tossed a spray of her blood at the monster. It hit the mist-engulfed demon’s head and ignited.

Muichiro remembered something Tanjiro had said, that Nezuko developed a Blood Demon Art of her own on their last mission. It was called Exploding Blood, an anti-demon flame that was harmless to humans. The young Hashira had thought it sounded extremely cool and had been eager to see it in action.

It failed to occur to Muichiro until now that anti-demon also meant anti-him. Because the moment Nezuko’s blood exploded, so too did his mist. Like a sudden gas fire, an eruption of pink flame engulfed the demon puppet’s upper half. Nezuko was knocked off her feet, and a phantom pain ripped through Muichiro’s being. For a moment, his mind went blank, awareness seared away in a wave of fire.

Then suddenly, he came to. His reformed body fell to the ground, unable to support itself. Probably because, as he soon realized, he was outright missing a good half of it. His left arm and leg and a chunk of his chest were burnt to nothing, and he couldn’t blink or feel his face either. The night air bit at his exposed muscles and nerves. It hurt. He felt his body regenerating, but it was slower than it should have been.

Nezuko was in front of him, kneeling down with guilt and concern written across her face. “I’m… okay,” he breathed out, his throat screaming. But then he heard the demons still moving behind him, and a different, more familiar fire engulfed him. Pain and fury mixed together to make red.

A roar filled the air, and the demons fell silent. His body began to regenerate faster. Nezuko looked past him with alarm, and he followed her gaze to see that the puppets were gone, a red mist rolling darkly in their place. The beasts in the mist growled, wary of further danger.

Muichiro closed his eyes and forced the Devouring Mist to submit and return to him. “Sorry you had to see that…” He opened his eyes again and looked away in shame. His rage got the better of him. After all this time, he should have had more control. But Nezuko shook her head and helped him to his feet. He noticed her pupils had narrowed to slits, and she was still on guard even as she tended to him.

Muichiro tried to smile for her. “It’s not your fault, so don’t worry. You couldn’t have known.” Both demons then looked warily towards the pond. It was calm now, and Muichiro still couldn’t sense the demon that had controlled those puppets, but he had a bad feeling.

“I’m worried about Hina,” he voiced aloud. “We should look for her.”

But he needn’t have bothered. “Muichiro? Nezuko?”

The two spun around in shock. Muichiro had been so distracted that he hadn’t even felt her approach. But the look Hina gave them was one of pure horror.

“What… what are you…?”

He realized immediately what she meant. Nezuko’s pupils were catlike slits, and a glance at the pond behind him showed his extra eyes had opened up, all six turquoise on teal and glowing brightly. The red mist clung to him, damningly incriminating.

This was bad. Muichiro forced the other eyes to close and swallowed a lump in his throat. He tried to speak, “Hina… wait-”

“No! You’re the monsters, aren’t you?! You were just trying to trick me!” Nezuko shook her head and tried to step closer, but the human girl pointed her rusty pitchfork at her in response. “Don’t get any closer! Just stay away!”

Then she turned and ran.

“Hina!” The two moved to go after her when more sounds came from the pond. More puppet demons crawled out of the water towards them. Muichiro let out a growl, the blood mist rising around him as he and Nezuko turned and prepared for another fight.

—

Hina ran through the dead silent village of Shimizu, no destination in mind. Her house was too close; she had to get as far away from the monsters as possible.

She was so stupid! Why did she trust two strangers wandering outside at night anyway? They probably weren’t even kids, just pretending in order to get close to her!

But then, why did they fight the other monsters? Why did they protect her? She thought they were trying to trick her, but…

Hina stopped running, halting on one of the bridges crossing the many streams flowing through the village. She looked back, hearing the sounds of fighting. No one came out of their houses to investigate. They were all too afraid.

What should she do now? Try to find help? But for who: herself, or those two fighting?

Underneath the bridge, a yellow light glowed, and the water began to rise.

—

Muichiro and Nezuko breathed out to calm their racing hearts as the last of the puppets crumbled away in the Devouring Mist. Muichiro couldn’t understand what the goal here was. These demons were pathetically weak; all they had was numbers with which to stall them. But stall them from what?

The answer came when a sudden chill ran through his body. A heavy presence, drenched in malice, radiated from the direction of the village, the same direction in which Hina had run off. Muichiro hissed, realizing how stupid he’d been. A flap of wings came from overhead, and he looked up to see Ginko flying towards them. “Ginko, find Yui! The demon is here!”

He didn’t wait for her response before he broke into a run, chasing after the girl. He heard Nezuko behind him, barely keeping up, but he couldn’t afford to slow down for her. The demon had shown itself; it was on the hunt, and Hina was all alone. He sniffed the air, and immediately slid to a halt.

Blood. The smell of blood hung in the air. Was he too late?

“Mmmph!” Nezuko tugged at his kimono and pointed ahead. He followed her finger and saw a familiar girl huddled next to one of the buildings.

“Hina!” He almost ran over, but managed to hold himself back. The girl knew they were demons and was probably still scared. “Hina, it’s Muichiro. Please come here; we’re not going to hurt you.”

“Mu…i…chi…ro,” the young girl spoke slowly and quietly. Something didn’t seem right; her voice sounded strange. “Mu…i…chi…ro.”

“Hina?”

She stood up suddenly and started to walk towards him. She moved stiffly, limping and lurching like a…

…like a puppet.

“Mu…i…chi…ro.” Hina stepped closer, and Muichiro took a step back, a warning growl in his throat. He sensed a presence heavy with blood and malice beneath the benign scent of a human. The girl was smiling, but her brown eyes were dark and vacant. His instincts screamed danger.

“You’re not Hina,” he said. A mist sword formed in his hand, and he pointed it towards the girl’s chest to keep her from coming any closer. “Who are you?”

The thing that was not Hina stopped walking, but she didn’t seem threatened. If anything, her unnatural smile grew bigger. She giggled, a haunting sound in the eerie silence. “Mui…chiro… Mui...chiro… Muichiro!”

Six water tentacles erupted from her back and chest, spraying blood and bits of bone from where they punched through. She gave him one more wide smile before her face split apart at the mouth, bones cracking as something forced its way out in a shower of viscera.

Hina’s blood splashed across Muichiro’s face. The heady aroma filled his senses, making him sick to his stomach. But he couldn’t move, paralyzed by the sight before his eyes. A gelatinous bubble in the vague shape of a long neck and head emerged. Inside was a child-sized human skull, a spinal cord and brainstem extending down the neck. The skull’s jaw was forced wide open, a single large eye floating within. The eye glowed yellow, the kanji for “two” crossed out and scarred.

“Muko… Muko has found you!”

It had no mouth, but its voice was high-pitched and muffled, as if speaking underwater. The tentacles moved towards him, but still Muichiro was frozen in horror. Nezuko shouted and shoved him back, standing between them, and the water demon’s eye shook with fury.

“Muko doesn’t care about you! Out of the way!” The tentacles moved almost imperceptibly fast, slamming into Nezuko and knocking her aside.

“Nezuko!” Muichiro finally snapped out of his trance and jumped back as the demon’s tentacles swiped at him next. His mist sword cut through the tendrils, but they simply regenerated and returned to the demon’s side. The monster was still wearing Hina’s corpse like a suit as it limped towards him, and he felt like he might throw up. This was his fault; he promised himself he’d protect her and he failed.

“Muichiro… Muichiro!”

“Stop saying that!” Muichiro snarled with fangs bared. The sound of his own name had never been so revolting before. “Who are you? How do you know me?!”

“How? What a stupid question,” the demon scoffed. “Muko knows you because Muko knows herself. Muko is Muichiro as Muichiro is Muko. We are both Mu. Both nothing.”

Muichiro felt a chill run through him, before his anger returned twicefold. This demon was utterly delusional. Listening to it speak so confidently, like it knew anything about him, made his blood boil.

“What the hell are you talking about?” He couldn’t keep the disgust out of his voice, nor did he want to. “Is that why you killed Hina? To get close to me? You think you have some sort of connection with me just because our names are similar? That’s complete bullshit. And besides, you’re wrong. The Mu in Muichiro means infinite, not nothing.”

“It is the truth,” the demon, Muko, insisted. “Muko has nothing, not even a body. But now Muko’s body has been found! Muko will take her body back and be nothing no longer!”

Muichiro didn’t need to ask what she meant by that. Hina and the puppet demons were evidence enough of this insane creature’s intentions. It was disgusting; that this demon could do such horrible things to her own kind, to a child! Did she even have a heart? Mist rose around him as he held up his sword. “That won’t happen. I'm not going to be a skin suit to some disgraced Lower Moon.”

“Disgraced?!” That seemed to rile Muko up. Her eye shook in its watery container, and suddenly the tentacles were flying towards him again. Muichiro cut through a few and turned to mist to avoid the rest. “Muko is not disgraced!”

“Really? Then why’s that number crossed out?” Muichiro snarked as he reformed behind her. His tone carried mock pity. “Did someone disappoint the Demon King?”

“Shut up, shut up!" the demon raged, tentacles waving wildly. "Muko should have been Lower Moon One! Muko won her blood battle! But the Demon King cast Muko out! He called her too unpredictable, too uncontrolled! But Muko was just teaching Lower Moon One a lesson! It’s not Muko’s fault that he was weak!”

Suddenly water erupted from a nearby stream and shot towards him along with the tentacles. Muichiro darted to the side to avoid the larger attack and swung his sword to cut through the smaller tentacles, but they reformed almost as quickly as he slashed them. Despite his banter, he could sense that this demon was powerful and very, very dangerous. He needed to kill it before it could hurt anyone else.

“Blood Demon Art: Devouring Mist!”

The red mist rose at his command, forming a beastly maw that swept towards the demon. But then Muko retreated into Hina’s body, and Muichiro found himself looking into the girl’s ruined face, eyes wide with agony in her final moments. A memory flashed in his mind. The Lower Moon Four, holding a dying Hayato hostage, and the roaring of the Devouring Mist as he attacked anyway. His breath caught in his throat.

No, stop!

The mist beast stopped in its tracks, jaws inches from Hina’s body. Muichiro shook, the mist wavering in time with his beating heart. What was he doing? Hina was human! Even if a demon was inside her body, that body was human. If his mist touched it…!

“Blood Demon Art: Water Blades!”

Slashes of razor thin water tore through the thinning mist and headed straight for him. Only Nezuko jumping in and throwing them both to the side at the last second saved him from being sliced into pieces.

“Nezuko! Are you okay?”

Nezuko huffed and nodded, but her face was strained. He quickly saw why; the attack had taken off her left leg, and cut deep into the other. A pang of guilt ran through him; Nezuko only got hurt because he hesitated.

Muko laughed as her head re-emerged from Hina’s. Her tentacles lunged forward, but Muichiro summoned a red mist sword in time to counter with an elongated slash. The blade cut through the tentacles and forced Muko back. Before she could retaliate, Nezuko’s blood, splattered across the ground, ignited. A wall of pink flame burst to life, separating them and the demon.

“Huh? What is-” Muko’s eye swiveled to the left, and her head sank back into her human shell as a sword cut through where it had been. The demon’s tentacles launched her body back as Giyuu landed before the wall of fire.

“Tomioka!” Muichiro gasped.

“Muichiro!”

“Nezuko!”

The sounds of their respective brothers calling their names brought an immense relief to the two demons. The flames died down as Yuichiro and Tanjiro ran to stand on opposite sides of the water demon, boxing her in between them and Giyuu. Muko emerged again, and Tanjiro’s face went pale with horror, while Yuichiro just grit his teeth in anger.

Muko’s eye shook. “Cheaters, cheaters! Five against one is so unfair! But it’s fine; Muko can play dirty, too!”

Suddenly multiple geysers erupted around them, leaving large sinkholes in the ground. Sinkholes from which more puppet demons began to crawl out of.

“What? But how?” Muichiro didn’t understand. Where was the water to control them coming from?

“This demon’s smarter than we thought,” Giyuu informed him, voice calm but body tense. “It built an underground river system beneath this whole village.”

“Sensei, look!” Tanjiro shouted suddenly. As far as they could see across the village, more geysers burst upward, and more demons crawled out of the holes left behind. A collective panic ran through the group of slayers.

Muko laughed. “Hurry, hurry! If you don’t, Muko’s toys will kill everyone!”

Suddenly, Muichiro realized that while this demon was delusional, she was not insane. No, she was clever. She had been planning for an encounter like this for a long time.

“Tanjiro, Nezuko, come with me,” Giyuu called suddenly. “We’ll take care of the demons in the village and protect the civilians. You two, focus on defeating this one.”

Muichiro and Yuichiro nodded, acknowledging his command. Muichiro smiled; he couldn’t help but feel more confident now that he was fighting at his twin’s side again. But that confidence fell away as he remembered that as long as the demon wore her human skin, he couldn’t fight at full strength. How could he get her to abandon it?

But he had no time to think, because soon the demon was attacking again, and a battle on two fronts began.

—

Yuichiro watched as Giyuu and the Kamado siblings cut through the closest puppets and ran deeper into the village. So much for being covert. The Master would have his hands full trying to explain this in the morning. He turned his gaze back to the demon they’d come here to kill.

He was no stranger to the gruesome scenes left behind by demons, but even he had to take a step back at the sight before him. That had to be a human girl, no older than twelve, whose body had been mutilated and was now being paraded about by this monster. It made him sick.

The demon’s water tentacles suddenly whipped out at both twins, forcing them to dodge. He cut through one, noting the jelly-like consistency of the tentacles that clung to his sword and slowed his swing. Yuichiro also noticed that something about his brother was off. He was moving but not attacking, his gaze fixed on the demon. Yuichiro wanted to ask him what was wrong, but this demon wasn’t giving him a chance. He ducked under a high swinging tentacle and readied a technique.

“Mist Breathing, Fourth Form: Shifting Flow Slash!”

He shot forward underneath the tendrils, aiming for the demon’s legs. But then the ground in front of it broke as a geyser erupted upward. Yuichiro was forced to stop and dodge as the geyser was redirected towards him. He reminded himself that the demon could control water, and there was an entire tunnel network’s worth of water beneath the village. He grit his teeth. All five of them together should have been more than enough for a former Lower Moon, but they were fighting on the demon’s home turf.

“Yui!” Muichiro shouted. Yuichiro reacted on instinct and brought his blade up as a sharp tendril sliced towards his neck. The demon was in front of him, its single eye glowing menacingly.

“Yui… Yu… Yu means to exist. Yu means to have something. It is the opposite of Mu! How dare you! You don’t deserve that name!”

Yuichiro had no idea what this demon was talking about, but those words struck a cord long since buried. “Shut up,” he hissed, “Don’t talk to us, you disgusting parasite.”

He forced aside the tendril and took a swing at the demon’s exposed skull. It didn’t seem to have a normal neck to cut, but since cutting the brains of the puppet demons killed them, it only made sense that the water demon’s brain would be its weakness as well.

But again, the demon reacted with unexpected speed, tentacles pulling itself back before his sword could make contact. As it landed, a cloud of white mist swept in and engulfed it. The demon seemed unbothered by the mist’s acidic touch, but the cloud still helped to obscure its vision. Yuichiro jumped in for another attack.

The demon retreated inside its shell again, and the remains of the human girl’s head suddenly stared back at him. It was enough to throw off his aim, his sword catching the arm instead of the neck. Said arm went flying as water gushed out of the wound. There wasn’t even blood at this point, just a hollow shell eaten away by the demonic liquid.

Yuichiro grimaced; no demon he’d fought before had ever stopped as low as this. Even if the girl was clearly dead, swinging his sword at a human child was not something his mind could easily reconcile. But of course, that was the demon’s plan; to take advantage of their empathy as fellow humans. No doubt it was why Muichiro still refused to attack.

Water tentacles swung through the mist, forcing Yuichiro back. One grazed his cheek, and a sharp, shallow pain blossomed from the wound. Yuichiro bit his tongue and mentally scolded himself; this demon was too fast and unpredictable for him to hesitate like this. He needed to cut its brain quickly.

Muichiro reformed behind the demon, a furious look on his face. It sensed him and twisted around, only to shriek and recoil as Muichiro’s claws slashed through its single yellow eye. The water tentacles suddenly went limp, and as his twin vanished back into the mist, Yuichiro saw his chance. He leapt forward, sword cutting through the goo-like body and striking the skull inside-

“Blood Demon Art: Water Blades!”

-but the jellish liquid slowed the momentum of his blade, stopping him from cutting through and giving the demon a precious second to react. Yuichiro pulled back his sword and braced himself, preparing for the onslaught of razor water to cut through him. But it never came. Someone else got in the way.

Muichiro clenched his teeth to hold back a scream as the blades tore bloody gashes through his body. He fell back against Yuichiro, who instinctively grabbed him and helped him to stand. Yuichiro shouted his name, but a sudden shrieking from the water demon stopped him from saying any more. Muichiro’s blood had splashed across the demon and its human shield, and where the blood touched its true body, the liquid substance began to melt with a hiss.

“It hurts! It hurts!” the demon screamed, stumbling away from them. “Bad blood! Bad blood!”

Yuichiro didn't know what was going on, and judging from Muichiro’s confused expression, he didn’t either. But it was clear that somehow, his blood was hurting the demon. But it didn’t last long. The monster raged as its body dissolved the blood and regenerated. “You meanies…! You bullies…! How dare you hurt Muko! Muko will teach you a lesson! Muko doesn’t need this village, so Muko will get rid of it!”

Suddenly the ground shook as both twins struggled to keep their footing. The ground started splitting, faster and more severely than before, as water bubbled up through the cracks. All of a sudden, Yuichiro understood what was happening. The demon was going to collapse Shimizu Village into the underground waterways. And if it did, the fall and collapse would kill everyone inside.

Muichiro must have realized the same thing. A determined expression crossed his face, and then he raised his hands and shouted. “Muko! Over here!!”

Yuichiro wanted to ask what he was doing, but the demon stopped, its single eye fixated on him. Muichiro went on. “It’s me you want, right? Well you can have me, but only if you catch me first!”

“You promise? Really promise?!” it gasped, suddenly pleading. It was disgusting, how much it sounded like a child in that moment.

Muichiro nodded. “I promise.”

“Okay! Muko likes a chase, anyway!” Its rage forgotten, the demon launched itself towards him, flailing tentacles forcing Yuichiro back. But Muichiro leapt away and took off running into the forest behind them. The demon laughed maniacally and pursued him.

“Muichiro!” Yuichiro shouted. His brother must have wanted to get the demon away from the village. But what was he doing, using himself as bait? He went to chase after them when he heard footsteps from behind.

Giyuu, Tanjiro, and Nezuko ran up to him, the latter two a little worse for wear while the Hashira looked untouched. “The village is safe,” Giyuu reported. “Where’s the demon?”

“Muichiro led it away into the forest,” Yuichiro explained quickly. His whole body was shaking with worry for his twin. “We have to go after him!”

Nezuko grunted and moved to follow, only for Tanjiro to stop her. “Wait, Nezuko! It’s almost morning! You need to get inside!”

Yuichiro’s blood ran cold. He’d been so focused on the battle that he hadn’t even thought about the time. He looked up and saw the sky above was growing lighter, blue shifting to orange as the first light of the sun crossed the horizon.

His heart beat faster and his mind screamed.

The sun was coming up.

—

Muichiro dashed through the dense forest, keeping his steps light as he wove through foliage that might trip him up. His hope was that he could lure the demon far enough from the village that she wouldn’t be able to control the water there. Her ability had to have a limit to its range, right?

“Don’t run! Muko will find you, Muichiro!” He saw the demon trailing behind him and smirked.

“Good luck! I told you, you have to catch me first!” He continued running, picking up speed as he did so, and Muko vanished amongst the trees. Muichiro knew he was faster than Muko inside her human shell. If she wanted to catch him, she would have to abandon-

His thoughts were interrupted as something crashed into him from behind. He hit the ground hard, a heavy weight on his back, but it vanished a second before a tentacle wrapped around his waist. The tentacle threw him into a nearby tree, his vision going white as his head slammed against the bark. Then it cleared, and he looked up into the face of the water demon. Muko had shed her human skin at last.

Oh, so you do have a heart, Muichiro thought with renewed disgust. Even for a morphed demon, there was barely anything human left of her. He could see a beating heart pumping blood through an immature circulatory system and up to her brain. Her amorphous water body reminded him of a slug as she crawled over him.

“Caught you!” she said in a gleeful, musical tone. One of her tentacles suddenly pierced through his chest, and Muichiro bit back a scream. A sizzling sound came from the wound, but Muko didn’t seem to care. “Now to keep your promise, Muichiro! Muko will bleed every drop of bad blood out of you and take what is hers!”

Muichiro pushed through the pain and flashed a fanged grin.

“Sorry, but that won’t be happening. Because I’m going to kill you, right here, right now.” White mist rose around him and the still bleeding wound. “Blood Demon Art-”

Muko’s eye shook as she realized what he was doing. She reared back. “No! Blood Demon Art-”

“Devouring Mist!”

“Water Blades!”

The two attacks clashed point blank. Red mist and sharp water slashes carved through the surrounding flora and tore up the earth. Trees were reduced to nothing before they could even fall. A thick cloud of dirt filled the air. It was over in an instant, silence falling around them.

Muichiro opened his eyes. All around him was an empty expanse of ruined land, stretching a good fifty feet in every direction. He felt a pang of guilt at the realization that all this destruction was partly his fault. He tried to sit up, but his body wouldn’t move. He felt the familiar tingling of his demonic regeneration all over, and assumed that his body must have been horribly damaged in the attack, but he couldn’t move enough to assess it properly. He couldn’t even feel any pain.

He could do nothing but stare at the sky, a sky he realized was quickly growing lighter. He had cut it far too close. He needed to pull his body into the shade before-

“You…!”

Muichiro’s eyes grew wide. That was the demon’s voice; she was still alive? His body had recovered enough for him to turn his head, and he watched as Muko’s goo-like body slowly reformed around her. Only a fragment of her skull remained, her brain near melted, but she was still able to regenerate. Her scarred eye swiveled with impotent rage.

Muichiro stared in horror. How did she survive the Devouring Mist? He could only assume her own Blood Demon Art had weakened it enough to save her from a direct hit. He cursed himself. He messed up and failed to kill the demon, and now both of them could only try to regenerate as the sunrise quickly approached.

“How dare you…!” Muko regenerated enough to move first, and she loomed over him. “How dare…!”

Voices shouted in the distance, almost going unheard. But Muko turned, and she seemed to realize for the first time the danger that was rising over their heads. Her pupil shrank, then looked towards the ground.

Muichiro felt his breath catch in his throat. Time seemed to slow to a crawl as his mind raced. The sun was coming up. His body had healed to the point that he could run to the shade before it reached them. But if he did that, then Muko would escape. She would dig into the earth and hide, and would probably flee the island entirely. They would never find her again. She would survive to kill countless more humans.

He couldn’t let that happen. A cold calm washed over him, one of realization, and of acceptance.

Yui… Nii-san… I’m sorry.

Time resumed. The sun rose higher, casting its light over the newly made clearing. Muichiro’s mist sword formed in his hand, and he thrust upward, the blade piercing Muko’s eye. Muko roared in pain, and Muichiro dug his claws into the demon’s gelatinous body. With all his strength, he lifted her above him as the sunlight reached them.

Muko burned first. As soon as the sun’s rays made contact, her watery form began to sizzle and evaporate. She screamed, a piercing, agonizing sound that didn’t stop until her skull, her brain, and finally her eye crumbled away. Slowly and yet far too quickly, Muko’s body burned in the sunlight. And then it was gone, and there was nothing to shield Muichiro any longer.

For the first time in two years, Muichiro felt the warmth of the sun, and no pain he had ever felt could have prepared him for it.

Fire consumed him. His clothes, his hair, his flesh, all began to burn, blacken, and crumble beneath the morning sun. Wave after wave of agony coursed through his body, his very cells crying out as the light of life rejected them. Every part of him was burning and burning and burning without end. There was no chance of relief. There was only pain, constant and beyond comprehension. A divine punishment, the gods looking down on him and judging him sinful for what he had done, for what he was.

Someone was screaming, and it took him ages to realize it was him. He couldn’t breathe, couldn’t think; all he felt was pain. The brief peace that he had made with his death turned to ash as primal instinct took over, clawing and clinging to life. He didn't want to die. He didn’t want to die! He didn’t want to die he didn’t want to die I don’t want to die I don’t want to die I don’t want to-!

“-chiro! We’re here, just hang on!”

A voice called out, but he couldn’t understand what it was saying. Then a shadow fell over him and blocked out some of the sunlight. Something green and black was held above his head, stopping the burning. But his arms and legs continued to crumble in the light. Something wrapped around his chest and pulled him up, and a new panic seized him. He screamed and thrashed, even as he no longer had limbs with which to fight back.

“Muichiro! Muichiro, it’s me! It’s Yui! I’m here! Nii-san is here!”

But his mind was still trapped in a primal terror. He couldn’t recognize the words or the voice speaking to him. He looked up into teal eyes filled with tears. More shadows covered him, shielding him from the light. But in his own mind, he was still burning.

“Get him to transform. He needs to make himself smaller.”

“Muichiro, listen to me! You have to transform! Turn into mist, so we can get you somewhere safe!”

He couldn’t understand. He tried to breathe, only to choke on his own ashes sticking to his throat. The voices gasped.

Then the thing holding him suddenly pulled him close. It was warm, and a rhythmic thumping filled his ears. A voice whispered to him, “Don't be scared. Nii-san is here for you. Nii-san is right here. Everything’s going to be okay, I promise…”

He stopped fighting. He clung onto that warmth and that soothing rhythm with all his being. Slowly, the burning stopped. The world gradually returned to him. He saw three figures leaning over him, two of them looking down with worry. But the third, the one holding him tight, the one crying… was his big brother. Tears fell from his brother’s eyes and landed on his cracked cheeks.

Tears of his own, blackened by ash, filled Muichiro’s eyes. “Nii… san.”

—

Yuichiro held his little brother close. His voice calling out to him, deathly soft and hurt beyond imagining, nearly broke him. The urge to just hold him close fought with the need to get him somewhere safe. But he couldn’t bear to move him. Part of him feared that his twin would crumble to ash completely if he did. It was too risky.

But Yuichiro didn’t care. He’d stay here all day if he had to, shielding Muichiro until the sun’s light no longer threatened him. He held him close and continued to whisper words of comfort.

“Yuichiro, look…!”

Tanjiro’s voice snapped him out of a daze he hadn’t even realized he’d fallen into. But he looked, and saw instantly what he meant. Muichiro’s body was starting to shrink. At first, Yuichiro thought he was taking a childish form like Nezuko often did, but the change stopped after a few seconds. He found himself looking down at his twin at the age of eleven, the same age as when he’d first become a demon. The sight of him, skin cracked and blackened by the sun, with ashen tears streaming down his face, would haunt Yuichiro for the rest of his life.

Muichiro pressed his teary face into Yuichiro’s chest and curled up against him. Like this, he seemed even smaller than he already was. Guilt gripped Yuichiro’s heart like a vice. This was his fault. If he had killed the demon sooner, if he hadn’t let his brother run off alone, if he had protected him from becoming a demon in the first place…!

“I’m sorry, Muichiro,” he held his twin close and cried. “I’m so sorry…”

Chapter Text

It was the middle of the day, and the Mist Estate was dark. Heavy curtains were drawn over every window to keep the sunlight out. It had been this way ever since the mission at Shimizu Jima.

Muichiro was all alone with his thoughts, a dangerous combination as of late. The training dummy in front of him was slashed to pieces with one swipe of his claws. It’s head flew into the air, and he lunged again before it could hit the ground. The image of Muko’s scarred yellow eye overlapped the dummy’s head as he split it apart.

Objectively speaking, the Shimizu Jima mission had been a success. The demon was dead, no slayers had been lost, and civilian casualties had been kept to a minimum. Minimum, because there was still one casualty. A girl named Hina, whose only crime had been going out at night to tend to her family’s horses. That girl was dead.

And it was all his fault.

Another training dummy was reduced to sawdust. Originally Muichiro trained with his sword, but that wasn’t sufficient to vent his frustration, so he used his claws instead. But that only helped so much. And seeing the state of the training room, with dozens of destroyed dummies torn apart by his hands, only made him feel worse. It was all too easy to replace the dummies with human corpses, bleeding red instead of dust and splinters. A massacre perpetrated by a monster. He was a monster. That’s why Hina ran away. That’s why he couldn’t protect her.

Muichiro knew he couldn’t save everyone. He’d witnessed the deaths of other slayers and civilians many times. But he had never failed to protect a human whose life was in his hands. Until now. Hina had been right there, right in front of him, and he should have kept her safe. But he failed.

He couldn’t even avenge her properly. His attack against Muko didn’t work, and he had no choice but to hold the demon in the sunlight, knowing he would die with her. And if it wasn’t for his companions, he would have. He would have burned until there was nothing left of him, a penance for his failures. A penance that now went unfulfilled.

Muichiro was alive. Alive and drowning in guilt and regret and anger. Anger at the demons. Anger at himself. The mist in his head pushed to smother those feelings, but Muichiro pushed back, knowing that it would swallow him too if he let it. His claws dug bleeding holes in his palms, the pain grounding him and keeping the fog at bay. He had no more dummies left to take his frustrations out on; no doubt Yuichiro would be upset by his lack of restraint.

Yuichiro.

Muichiro’s anger was doused in cold despair. He wished Yuichiro was here. He needed his big brother with him. He needed someone, anyone, to distract him from his thoughts. Anything would be better than being alone with the fire and the fog battling inside him, fraying his sanity at the threads.

Where was Yuichiro? The mission was only supposed to take a few days; he should have been back by now! Muichiro hadn’t even wanted to let him go alone, but his twin insisted, saying he needed time to recover before going out on missions again. But Muichiro didn’t need time to recover! He needed to know his big brother was safe! Where was he?!

His claws dug in deeper, blood dripping onto the floor. He was so caught up in his own head that he barely heard a door open, and a voice call out, “Muichiro? I’m home!”

That voice! Muichiro rushed out of the room, ignoring the mess he left behind. He ran to the main entrance to see his brother standing in the open doorway, looking around for him. The urge to run up and grab him and never let go was overwhelming, but the sunlight shining behind his twin stopped him cold. Muichiro froze, several feet from the light yet unable to get close, something inside him screaming to stay away, to run, to hide. Yuichiro’s eyes went wide at the sight of him, and he quickly moved to close the door, blocking out the sunlight and throwing them into darkness once more.

It was as if a spell had been broken, and Muichiro was free to move again. No sooner did Yuichiro turn around then he was suddenly enveloped in a tight hug, Muichiro clinging to him as if he could disappear at any moment.

Yuichiro returned the hug after a moment of stunned surprise. “Hey… miss me?”

He sounded so casual, as though he hadn’t left Muichiro all alone for three days straight. “Where were you…?”

“The mission just ran a little long, that’s all,” Yuichiro answered, but Muichiro didn’t think he was being truthful. And he was right, as it was only after he finally let go that Muichiro noticed the bruises and bandages on his face and neck.

“What happened?!” he shouted with alarm, leaning in closer to inspect the damages.

“It’s nothing! I just got… thrown into a wall, once.”

“What?!”

“I told you, it’s nothing. I already had a doctor look at it, and nothing’s broken or bleeding. It’ll heal up in a couple of days. The demon was a weak one; I just got caught by surprise.”

His words did nothing to reduce the horror Muichiro felt; if anything, he felt worse. Yuichiro was caught by surprise because he wasn’t there to watch his back. Yuichiro kept talking, oblivious to his distress.

“I’m sorry for being late. Maybe next time, you can stay at the Butterfly Estate? It can’t have been easy being all alone here.”

Next time?! This time was bad enough! Muichiro wanted to scream, but his voice lodged in his throat. Mist filled his vision, making it hard to see.

He missed the way Yuchiro’s nonchalant expression fell like a crumbling mask, clear concern showing in his eyes. “Mui? Are you okay?” He couldn’t answer, and his brother’s worry grew stronger. “Come on, let’s sit down and talk a bit.”

He grabbed his hand and started to pull him towards the living room, but Muichiro wouldn’t budge. He suddenly didn’t want to be around when Yuichiro discovered the state of said room. It wasn’t as bad as the training arena, but…

…but he couldn’t avoid it, either, so he relented and let Yuichiro drag him along. And just as he expected, his brother froze at the sight of the room. Tattered scraps of countless origami littered the floor, and the table on Muichiro’s side was covered with dozens of nervous claw marks. When Yuichiro still didn’t move after a few seconds of staring, Muichiro softly said, “Sorry about the mess…”

That snapped Yuichiro back to reality, and he shook his head. “Don’t worry about it.”

He led him to the table and they sat down, side by side instead of across from each other as they usually did. Muichiro anxiously traced the gashes he’d left in the table while he waited for Yuichiro to speak. And then after a long moment of silence, he did.

“…I have some good news. Tanjiro and Nezuko are back from their mission.”

At the sound of the two siblings’ names, Muichiro lifted his head, a spark igniting in his chest. Yuichiro continued, “They’re recovering at the Butterfly Estate. I was thinking we could go visit them tonight after the sun goes down.”

“Why not go now?” Muichiro was eager to get out of the manor after being stuck inside so long, and he wanted to thank Tanjiro for helping to protect him from the sun back on Shimizu Jima. Most of all, though, he wanted to see what Yuichiro would say to his question.

But as he expected, his twin’s tentative smile turned into a frown. “Mui, you know why we can’t do that.”

The spark in his chest went out, and he turned his head back down to the ruined table. “Right…”

He had no one to blame but himself, really. What did he expect? He’d gone into a panic from just trying to get on a boat to go back home, so of course Yuichiro wouldn’t trust him to keep himself together long enough to get to the Butterfly Estate. He hadn’t been able to go near the sun for two weeks, so why would that change now?

Coward. You’re a coward.

Yuichiro’s frown deepened. Slowly, he reached a hand towards his brother. “Mui-”

A tapping at the window interrupted him.

—

Now what?

Whatever this was, it had better be important. Yuichiro had had a long three days, and right now, all he wanted to do was spend time with his brother. It was plainly obvious that Muichiro was upset at being left alone for so long, and while Yuichiro hated causing him so much distress, he didn’t know what else to do. Muichiro wasn’t okay, no matter how much he tried to deny it. And it was up to Yuichiro to protect him while he recovered.

Reluctantly, Yuichiro pulled away from his twin and stood up. He moved to the living room window and pushed the curtains aside to see Ginko perched outside. He opened the window to let her in; why was she here?

“New mission! New mission!” Ginko’s announcement answered his question immediately. His frown turned into a scowl. A new mission already? And another one that would take more than a night of traveling to reach in a reasonable time.

But even worse was that Muichiro was right there. Yuichiro saw his eyes light up, a semblance of his usual hopefulness returning to him, and though that should have made him happy, all he felt now was dread.

Ginko kept talking as she flew right up to Muichiro. “New mission! Head west and investigate the disappearances near the village of Hinohara!”

“Oh, I know that place!” Muichiro said, his eyes glowing even brighter. “Mitsuri told me about it! She says that there’s a shop that sells amazing sakura mochi! We could get some for her after the mission!”

“Hey, hold on-!” Yuichiro started.

“That’s a great idea, Muichiro! You’re so kind!” Ginko praised him. Of course she would encourage him. Stupid suck up of a bird...

”Oh, and they sell dango too, Yui! Doesn’t that sound exciting?” Muichiro continued. There was a desperate note to his voice, like he was begging for him to agree.

”That’s great…” Yuichiro growled as he stomped back to the table. He had a feeling Muichiro was trying to guilt him, intentionally or not, into taking him along on this new mission. And it was certainly working in the sense that he felt guilty for what he was going to have to do. But he had no intention of letting his twin force himself into a situation that he wasn't mentally prepared to handle. "But I never said we were going.”

”But we have to! It’s a mission from the Master!” Muichiro insisted, Ginko nodding along beside him.

“I don’t care,” Yuichiro hissed. The anxiety he felt was quickly turning to agitation. “We’re not-”

“When are we leaving? If it’s tonight, we’ll have to-”

“Muichiro!”

Yuichiro’s shout shocked his twin into silence. Ginko too was startled, looking at him with wide eyes. Yuichiro took deep breaths to calm himself before he could get any more wound up. The last thing he wanted to do was crush Muichiro’s hope. But for just a second, he saw his little brother’s face, charred black and crumbling, and his heart squeezed painfully. “I’m going. You’re staying here.”

Muichiro’s cheer shattered like a dropped mirror. He went deathly still, and his snakelike pupils appeared before vanishing a second later. All he could manage was a small “Huh…?”

Yuichiro swallowed a lump in his throat. “Think about this logically. This isn’t a mission that’ll be finished overnight. I’ll have to travel during the daytime. I don’t want to have to put you through that.”

“That’s what you said last time,” Muichiro said, quiet at first but steadily growing louder. “Is that just going to be your excuse from now on? To keep me from doing anything?”

“It’s not like that! I’m trying to keep you safe!”

“Keep me safe? What about you?! You got hurt because I wasn’t there to protect you!”

Yuichiro flinched. His wounds from that battle were superficial, but he should have known Muichiro would blow them out of proportion. He would do the exact same thing if their situations were reversed. “Muichiro, don’t you remember what happened when we left Shimizu Jima? I won’t force-”

“You’re not forcing me to do anything; I want to come with you! What happened there won’t happen again! I’m not scared, and…” Muichiro looked ready to burst into tears. “…and I’m a Hashira, too! I have responsibilities! You can’t just keep me here forever! I have to make up for what I did!”

“What you…” Realization hit Yuichiro, and his anger melted away. He should have known they’d have to talk about this eventually. “…Muichiro, I know you feel guilty about what happened to that girl-”

“Hina.”

“…Hina, but you can’t dwell on it like this. You did-”

“Don’t try to tell me I did everything I could,” Muichiro interrupted him harshly. “I didn’t. I could’ve done better. And if… If I wasn’t like this…” He glared at his claws and clenched them tight, drawing blood. “…then I could have saved her! I know it!”

Tears gathered in his eyes, and Yuichiro felt his heart breaking. “I’m sure Hina wouldn’t blame you for what happened.”

“Are you sure? The last time I saw her alive, she called me a monster. She told me to stay away from her and ran. That’s how the demon got her.” Muichiro’s anger drained away, and he just looked miserable. “If I were human, she wouldn’t have run away. I could’ve protected her.”

Yuichiro’s eyes went wide. Muichiro hadn’t told him that; no wonder he was so upset. But he could see where this was going now, and he didn’t like it. “No, Muichiro, you’re not doing this again. Being a demon does not make you a monster. You’re a good person; the fact that you wanted to protect Hina is proof of that.”

“That doesn’t change the fact that she’s dead because of me.”

“No, she’s dead because of that demon! You’re not to blame!”

“That’s easy for you to say! You’re still human! People aren’t afraid of you! They’re not scared that you’ll hurt them! But me… How can I protect people if…” Muichiro choked back a sob and buried his face in his hands.

“Muichiro…” Yuichiro cautiously reached out a hand, but the moment his fingers touched his twin’s shoulder, he jumped, startling them both. Muichiro uncovered his face and turned away.

“I… I’m sorry. I just need some time alone. I’ll see you tonight.”

Before Yuichiro could say anything, Muichiro burst into mist and fled the room. Yuichiro didn’t even try to stop him. He just sat at the table, cursing his incompetence; he couldn’t even comfort his little brother.

Ginko looked at him regretfully, as if wondering if what had just happened was her fault. Yuichiro reached out a hand and gently smoothed her feathers down.

“It’s not your fault. It's mine. I’m the one who messed up.”

He just didn’t know how to fix it.

—

The walk to the Butterfly Estate was long and quiet. Neither of the twins spoke a word, still upset from their argument earlier. Dark clouds hung overhead, and as the estate came into view, it started to drizzle. Muichiro turned into mist and flew ahead to escape the rain, leaving Yuichiro to walk alone. When he finally made it inside, he couldn’t find his brother anywhere.

After a few minutes, he gave up and found Kiyo to take him to Tanjiro’s room. Talking to him had been the whole reason they’d come here, and he still planned to do it even without Muichiro. Upon reaching the room, he bid Kiyo goodbye and knocked on the door. Tanjiro’s voice called for him to come inside.

He did so, and found Tanjiro lying in bed with various patches and bandages on his face and hands. His toddler-sized sister sat next to him, folding origami.

“Yuichiro! I’m glad you came by!” Tanjiro greeted him happily, beaming like the sun. “Is Muichiro with you?”

Yuichiro shook his head. “No, but I’m sure he’s somewhere around here.”

Tanjiro looked concerned hearing that. Nezuko also grunted, her eyes frowning, before jumping off the bed. She ran up to Yuichiro and held something out in her tiny hand, a little black origami cat whose ears had been painted turquoise. He took it from her and examined it carefully; it wasn’t as good as Muichiro’s, but it was decent.

He nodded. “You did a good job on it.”

Nezuko beamed and then rushed out the door behind him. Yuichiro turned to Tanjiro with a questioning look, and the other boy laughed. “She probably wants to give Muichiro the other one. She’s been waiting to give those to you for days!”

“I see.” A gift like that might help cheer Muichiro up. More than Yuichiro himself could, anyway. He sat down in the chair next to Tanjiro’s bed. “So, you look like you’ve seen better days.”

Tanjiro laughed and waved it off. “Don’t worry, it looks worse than it is! It’s thanks to Tomioka-sensei’s training. Without it, I might not have been able to survive against the Lower Moon.”

“The Lower Moon?” Yuichiro blinked.

Tanjiro nodded. He explained the details of his mission, of how he and Nezuko fought off Lower Moon Five on Mount Natagumo until Giyuu arrived and beheaded it. He also told him about something called the Hinokami Kagura, a dance passed down through his family that made his movements stronger and faster, as if it were a breathing style of its own. Yuichiro had no idea what he was talking about, but it sounded impressive.

“But, it has me thinking… that I might not be fit to be the Water Hashira,” Tanjiro said with a frown. “The Hinokami Kagura feels more natural than Water Breathing ever did. I need to learn more about it.”

Yuichiro didn’t know what to say to that, but it was true that Tanjiro’s nichirin blade was black instead of the blue that Water Breathing users possessed. “So what? Are you going to stop being Tomioka’s tsugoku?”

“I don’t know. But I’ll figure it out.” Tanjiro decided. “Anyway, enough about me. How have you been?”

“I’ve… been better.”

“Have you been getting enough sleep? You don’t look like it.”

Tanjiro was right on the mark there. His head was pounding, but a lack of sleep was something he’d grown used to lately. Rarely a night went by that he didn’t dream of that day, of his twin burning in the sun, writhing and screaming. Sometimes he was able to save him; other times he was left cradling his ashes. When that happened, seeing Muichiro alive was the only thing that could calm him. These past three days, he hadn’t slept for more than minutes at a time, afraid of what he might see in his nightmares.

“No, I haven’t. But I’m used to it, so don’t worry about me. I’ll sleep now that I’m back home.” That wasn’t a total lie, at least. He slept better when he knew Muichiro was safe.

Tanjiro still looked worried, but he didn’t press him. “I see… How about Muichiro? Is he doing better?”

Yuichiro’s troubled look was answer enough. Tanjiro’s frown deepened. “Is it that bad?”

“Yeah. He still won’t go anywhere near sunlight, and he was really upset when I had to go on a mission without him. And now I have to go out again, and he’s not taking it well.”

“Is that why he’s not here?” Yuichiro nodded. “Well, Muichiro’s his own person. Why not let him come with you?”

“Are you serious? Of course he’s his own person, but he’s not ready to be near the sun again. I won’t put him through that.”

“He probably wants to be there to keep you safe, though,” Tanjiro pointed out.

“You think I don’t know that?” Muichiro had said as much, after all. “But I want to keep him safe, too. I couldn’t do that back on the island, so I have to protect him now.”

Tanjiro tilted his head. “What do you mean? You did protect him.”

“No, I didn’t. You did. When I saw Muichiro like that, I was so scared that I froze. But you didn’t even hesitate; you ran right in to help him.” Yuichiro felt tears coming to his eyes, but he didn’t want to start crying, not in front of Tanjiro of all people. “Muichiro might’ve died if it wasn’t for you.”

“That’s not true, though,” Tanjiro said with a gentle, understanding smile. “You were only a second behind me. Even if I hadn’t been there, I know you would have saved him. Please don’t be so hard on yourself; you did everything you could.”

Yuichiro didn’t believe that; there was so much he could have done to prevent what happened. But Tanjiro was too good a person to accept a response like that. He sighed. “Tanjiro… I wanted to thank you for saving Muichiro. I know I haven’t been kind to you, and you did nothing to deserve how I treated you. But you still saved him. So… thank you.”

“Yuichiro…” Tanjiro blinked, stunned, but soon he was smiling again. “You don’t have to thank me. Muichiro is my friend. Both of you are, and I’m happy to help in any way that I can. And there’s no hard feelings either, so don’t worry about it!”

Yuichiro wiped away his tears. He felt relieved to hear that, like a weight had been lifted from him. “You're… a really good friend, Tanjiro.”

Tanjiro laughed. “Thank you! Coming from you, that means a lot!”

Yuichiro tried to ignore the warmth in his face. Tanjiro’s kindness really was very similar to his father’s, but… Tanjiro was Tanjiro. There was no other way to describe it; he was a uniquely kind person. A comfortable silence fell, only to be broken when Tanjiro asked, “So what will you do? About the mission?”

“I… I have to go alone. Muichiro’s not ready.”

“He’s not, or you’re not?”

Yuichiro flinched. How was Tanjiro so good at reading him? That horrible image of Muichiro’s burned face flashed through his mind again, and he felt sick. “…Both of us. I watched him burn alive, Tanjiro. I can’t bear to see that again.”

“I get it. Since that mission, I’ve sometimes imagined Nezuko in Muichiro’s place, and it scares me.” Tanjiro placed a hand over his heart. “But then I think that Nezuko and I are both fighting hard to make her human again. It’s not easy, and we could die without accomplishing that. But you still have to try, even if you’re scared, because you won’t get anywhere by standing still.”

Yuichiro sighed. He knew that Tanjiro was right. He had known from the start. But he’d subconsciously thought that, as a demon, Muichiro couldn’t truly be hurt, so his almost dying had been a horrific shock. He’d become the overprotective big brother again to make up for not being as careful as he should’ve been. He knew that wasn’t healthy for either of them, but he still did it, because he was scared to death of losing his twin, his other half.

“And besides, we’re stronger when we’re together. We protect each other, and give each other the strength to keep fighting. It must be the same for you and Muichiro, right?”

There was no denying the truth of that statement. Yuichiro almost felt angry at how right he was; where did a fifteen year old boy get this kind of wisdom and maturity? But he and Muichiro were indeed at their strongest when they were together. And in the end, Yuichiro hated being separated from his brother just as much as Muichiro did.

But he was still worried. What if Muichiro was still upset with him? What if he tried to apologize, and they just got into another argument?

“I get that, but… I don’t even know how to approach Mui right now. The girl who died called him a monster and it’s really gotten to him. But I don’t know how to make him understand that that isn’t true.”

“If that’s how you feel, then talk to him. Tell him that.”

“But I’m not a demon. I’ve never experienced that. Anything I say will-”

“You don’t have to be able to relate to someone to help them,” Tanjiro interrupted him. “Sometimes, just being there, lending an ear or a shoulder to cry on, is enough. Whatever Muichiro is going through, just show him that you’re there for him.”

“But I tried that, and he brushed me off!”

“Maybe it just wasn’t the right time. No amount of talking will help someone if they’re not in the right mind to accept it. But if you try again, when both of you are ready to talk, then maybe he’ll be ready to listen too.” Tanjiro’s mouth rose in an encouraging smile. “You can’t give up, Yuichiro. You have to keep trying until your feelings reach him.”

Yuichiro didn’t have a response to that. He held his tongue and looked at the ground. The right time? How was he supposed to know when the right time was? Ah, but he was overcomplicating this, wasn’t he? Most likely, there was no answer to that question. He would only know when the time came.

His face steeled into a look of determination. “…Okay. I will. Whatever it takes, I’ll keep trying until he listens.”

Because Yuichiro was still scared, and he didn’t want to see Muichiro hurt like that again, but he couldn’t bear to lose him. To let them drift apart again. Whether they were human or demon didn’t matter. Yuichiro promised himself that he would help his twin, and that he would stay by his side, matter what.

—

A forlorn cloud of mist wandered the halls of the Butterfly Estate. Muichiro was so lost in his head that he didn’t give any concern to his surroundings. Even a high-pitched wailing from one of the patient rooms failed to grab his attention for more than a few seconds. Whatever it was, he would probably make it worse anyway.

He shouldn’t have said what he did to Yuichiro. It wasn’t his brother’s fault that he didn’t understand, and frankly, Muichiro didn’t want him to understand. Because understanding would mean becoming a demon, and he would never wish that fate for his twin.

Eventually he floated past an open door, and something did catch his attention. Because outside the door was the garden, the rain falling heavily by now, and there was someone standing out in the storm. Muichiro reformed himself and peered closer, easily making out a mismatched haori. Of course, if his tsugoku was here, it only made sense for Tomioka to be here as well. But what was he doing out in the rain?

Then he remembered that the Water Hashira had helped to protect him from the sun on Shimizu Jima, and he still needed to thank him for that. And so, after a brief moment of reluctance, he stepped out into the pouring rain and approached the man.

“Tomioka?” he called, not wanting to startle him.

A second passed before Giyuu turned around. He seemed like he might have been surprised to see him, but Muichiro couldn’t read him well enough to be sure. “…Oh, Tokito. It’s you.”

Muichiro nodded. “Why are you standing out in the rain?”

They were both thoroughly soaked by now, though neither seemed bothered. As a demon, Muichiro wasn’t affected by the cold, though he couldn’t understand how Giyuu wasn’t even shivering. The Water Hashira took a moment to think before responding to his question. “I like the rain.”

Muichiro waited for him to elaborate, but he didn’t. For a moment, they were both silent until Giyuu suddenly asked, “How are you holding up?”

“Huh?” Muichiro blinked, not expecting the sudden switch in topic. “What do you mean?”

“Well, you almost died on our last mission. I haven’t seen you since then, so I was wondering how you were doing…”

Giyuu trailed off awkwardly, as if not sure how to finish his explanation. But Muichiro was surprised to hear him express his concern so openly. “Well… I…”

Should he say anything? The last time he did, he lashed out at Yuichiro and drove a wedge between them. But Tomioka was older, calmer, and despite his awkwardness, he had more worldly experience. And besides, what damage could talking do that hadn’t already been done? “I’m… not doing well.”

Giyuu raised an eyebrow, but he didn’t speak. Muichiro watched him for a few seconds, then went on, slowly finding his words. “I did almost die, but… I don’t really remember it well. There’s a thick mist over my memories when I think back on it. But whenever I see sunlight, I get this intense fear, worse than it’s ever been before, and I don’t want to go anywhere near it.”

“Ah,” Giyuu nodded. “That’s probably your subconscious remembering the fear you felt. Kocho told me about it before; it’s normal.”

“But it’s debilitating! It’s keeping me from doing what I need to be doing!” Muichiro felt that familiar fire building up again.

“Have you been seeing anyone for it? You might need to-”

“No, I haven’t! I’ve been stuck at home for two weeks because Yui doesn’t trust me to go anywhere!” And though it went unsaid, he himself had refused to see anyone. Who could - or would - help a demon? “And anyway, I don’t have time for something like that! I need to get back out there, to make up for what I did!”

“Hm? What did you do?” Giyuu looked confused now.

“Don’t pretend you don’t know,” Muichiro scowled. “I’m talking about Hina, the girl who died. I couldn’t protect her.”

“Oh…” A look of understanding dawned in the Water Hashira’s dark eyes. “And you blame yourself?”

“How could I not? I promised myself I’d keep her safe, but she saw I was a monster and ran away, and that water demon killed her!” The fire burned stronger, searing his insides. “She was just a child! I can’t even imagine how painful it must have been, how terrified she must have felt! But instead of doing anything to make up for her death, I’ve just been wasting away here, stuck in my own fears!”

“Tokito, you’re being too hard on yourself,” Giyuu said, an edge of steel lining his voice. “You’re acting like you made a choice to let her die, but if she really died because of you being a demon, that’s not something you could have changed. You can’t help being what you are.”

“But I still could have kept her safe!” Muichiro insisted. “Humans have been scared of me before, but I’ve always kept them safe! I wasted time fighting those puppets when I should’ve detected the real threat sooner!”

“We all failed to find the demon. It was smart and dug tunnels and streams in order to move undetected. No one could predict what it would do.”

“But-”

“It’s easy to look back and think about what you could have changed. But you can’t change the past.” The look in Giyuu’s eyes was far-away, looking at something only he could see. “The dead won’t come back, no matter how much regret you have.”

Muichiro flinched. Logically, he understood that. But his heart wouldn’t accept it. “…So what then? Am I just supposed to accept that her death was fate? That there was nothing I could have done?” He felt tears come to his eyes and mix with the rain. “That’s too cruel…”

“Some things are out of our control. For one reason or another, there are tragedies we can’t prevent, even as Hashira.” Giyuu’s voice grew soft and was almost lost in the rain if not for Muichiro’s keen hearing. He stepped closer and placed a hand on the younger’s shoulder, an awkward but comforting gesture. “You’re not a monster. Monsters don’t feel guilt. They don’t regret those they couldn’t save. So don’t blame yourself; you did everything right.”

Muichiro wanted to believe him. But if he had done everything right, then Hina would still be alive. His voice sounded pitiful, choked with tears. “No, you’re wrong… I… I almost died. I should have died! The sun gives light and life to the world and it nearly killed me! Only a monster would burn in the sun, so how can I be anything but a monster?”

“Demons burn in the sun. That’s just how it is.”

“Demons are mon-”

He stopped; he almost missed the pitter patter of tiny feet through the rain, but the presence was easy to detect. Muichiro turned to see Nezuko run out onto the engawa. Her eyes lit up at the sight of him, but she stopped at the edge, looking nervously at the rain. He could see something cupped in her hands.

“Are they?” He turned back to Tomioka, who had his head tilted, as if genuinely curious. He glanced to the side, and Muichiro followed his gaze back to Nezuko. Slowly, his overwhelming emotions ebbed away as he approached her.

“What do you have there?” he asked. Nezuko took a step back and held out her hands, opening them to reveal a white origami cat with turquoise ears.

“Did you make this?” Muichiro’s claws were still wet, so he didn’t take it, but he admired her craftsmanship from afar. Nezuko nodded. “It’s good. You’ve really improved.”

Nezuko beamed and sat down on the engawa. Muichiro sat beside her, careful not to get her wet. He couldn’t help but smile as he looked at her.

“Tokito,” Giyuu came closer, but stayed in the rain. “Tell me, is Nezuko a monster too?”

Muichiro hadn’t expected a question like that; the shock of it turned the fire in his veins to ice instantly. “What? No, of course not! Why…”

Giyuu looked at him knowingly, and Muichiro realized he’d fallen right into his trap. He looked down at the girl in question, who stared back at him curiously. Her pink eyes were bright with innocence. Such innocence… he couldn’t explain why he blamed himself but not Nezuko, who also failed to save Hina. But Nezuko just seemed… pure, in his eyes. She had never hurt anyone; she wasn’t a scary, dangerous demon. Not like him.

But you would burn in the sun, too.

The thought came unbidden to his mind. Immediately, a wave of guilt and revulsion wracked through him for daring to think something so awful. And yet, it brought him a peace of mind he hadn’t had before. This sweet, kind girl would also burn under the life-giving sun. The gods would judge her for something she couldn’t control. In that case, had he really done anything wrong? Even if he had saved Hina, would the sun have still rejected him?

Tomioka was right. Whether we’re good or bad demons, we’re condemned all the same.

The gods, the Demon King, even life itself, were truly cruel. What did they do to deserve this? They were only children.

“…It’s not fair. It’s not fair that we have to live with this curse. It’s not fair that innocent people have to suffer because demons exist!” The fire roared to life in his veins once more. “It makes me angry; so angry that I can’t stand it!”

“If you feel that way, then fight. Put that anger into your claws and sword, and wield it against the demons. Fight so that her death was not in vain.”

Muichiro looked up in surprise. He looked at Giyuu, and saw anger in his eyes. Anger much like his own. He had expected more placating words of comfort, but it seemed that perhaps Giyuu understood his feelings after all.

Tomioka… what have you suffered?

“But… Nii-san…”

He stopped. Yuichiro had tried to tell him the same things. That he wasn’t a monster. That he wasn’t to blame. And yet he’d rejected his words and yelled at him. Yuichiro was only concerned for his safety and well-being. But he never considered how Yuichiro was also suffering the scars of that night, that he was also afraid and coping in any way he could. He’d been too wrapped up in his own pain to see that.

"I... I'm going to find Nii-san now."

Muichiro stood up. He was still scared, but he didn’t want his fear to keep him from doing what needed to be done. His anger fueled him and gave strength to his conviction. He would continue to fight. There were still evil demons to kill, and innocent humans to save.

And he had a big brother to talk to. To really talk to, at last.

As he prepared to leave, he suddenly remembered the reason why he came out here in the first place. “Tomioka?”

The Water Hashira looked at him, and he continued. “Thank you for saving me on the island. And… Thank you for talking to me. I appreciate it.”

“Oh…” Giyuu looked away. “You don’t have to thank me… but, you’re welcome.”

Muichiro chuckled; Giyuu was surprisingly wise, but it was clear he was not used to being praised. It made him seem more approachable, though. He waved goodbye to him and Nezuko, but before he could go, Nezuko grunted and held out the white cat.

"Oh, right. Thank you!" Muichiro smiled as he took the cat. It wasn't perfect, some edges were folded unevenly, but she had tried her best, and that's what counted.

Maybe the same could be said of him. He wasn't perfect either; he'd made mistakes that he regretted. But he had tried his best. Maybe, someday, he could believe that.

—

The rain stopped after a few hours. Muichiro stood outside the gates to the Butterfly Estate, waiting for his brother. After an uncertain amount of time, he heard the doors open and a pair of footsteps walking down the path. He looked and spotted Yuichiro heading towards him. Yuichiro’s eyes went wide upon seeing him, and he hurried to catch up to his twin.

They looked at each other without saying a word. Muichiro was suddenly nervous, and he knew his brother was too. But he swallowed his fear and spoke, not wanting to miss this chance. “Nii-san, I-”

“Muichiro.” He froze at the sound of his name. Yuichiro reached out and took his hands in his own, and looked into his eyes. Muichiro wanted to divert his gaze, but something told him not to look away.

“Nii-san?”

“Mui, I… I want you to know that, whatever you’re going through… that it’s okay, and I’m here for you! It’s okay if you’re scared of the sun, because I’m going to be right here to help you through it. And whenever you start to think that you’re a monster, or that you’re less than human, I’ll be here to tell you that that isn’t true. And…”

His confident speech started to falter, the nervousness beneath showing itself. “…I hope you can forgive me for leaving you alone. I’m sorry; I was scared, too. I didn’t want to see you get hurt again. But now, what I really want is… is… ugh…”

He groaned and finally broke eye contact, fighting off the fog, but he didn’t let go of Muichiro’s hands. The young demon struggled to find his words, his own planned speech now in shambles. Why was Yui apologizing? Muichiro was the one who should be saying he was sorry!

“N-No, you don’t have to apologize! You did nothing wrong! I was only thinking of myself, and I never considered how you were feeling. I was just… so angry. Not at you, but at myself. For not saving Hina, for being scared of the sun, and… just for being what I am. A demon.” He curled his fingers around Yuichiro’s and squeezed. “But I don’t want to be scared anymore, and I want to use that anger for something good. I want to fight at your side, and I want you to fight at my side. Together, like we always have.”

Yuichiro looked at him with surprise. He seemed at a loss for words. But then, he closed his eyes, breathed in and out, and opened them again.

“Muichiro, you’re going to be human again, one day. You and I will make that happen, and we won’t stop fighting until we do.” He smiled, trying to look confident, even if he didn’t quite succeed. “And I want to fight alongside you too, the whole way. So, if you still want to come on that mission… well, I’d feel a lot better having you with me.”

“Yui…!” Muichiro pulled his brother into a tight hug, ignoring the surprised squeak he let out. Relief flooded through him. “Yes! Of course I’ll come with you!”

“That’s great… but…!” Yuichiro gasped as something cracked. “Too tight…! Mui!”

Muichiro blushed and let go, letting his brother gasp for air and bend his spine back into place. He quietly berated himself; he needed to be more aware of his strength as a demon. Humans were fragile, after all. But Yuichiro was soon grinning again, showing there were no hard feelings.

Muichiro grinned back. Even if he was a demon, at least he would always have his brother by his side. They began the walk back to their home, taking in the quiet night and the smell of fallen rain.

“Hey, Mui?” Muichiro looked at his brother, waiting for him to continue. “Before we leave… do you want to watch the sunrise? We’ll play it safe, of course. We’ll stay by the door so you can get inside quickly, and we’ll keep blankets around, and-”

Muichiro’s eyes widened as Yuichiro went on. He hadn’t seen the sunrise since Shimizu Jima. He’d been too scared and angry at himself to try. But with Yuichiro at his side, he felt like he might be able to do it. He took his twin’s hand, putting a stop to his brotherly worrying.

“Yeah, I’d like that…” His smile turned into a smirk. “…after you get some sleep! You look awful!”

Yuichiro was caught off guard, but as soon as the shock passed, he burst into laughter. “Yeah, I guess I should… Do I really look that bad?”

Muichiro nodded. His older brother looked like he hadn’t slept in three days, dark bags under his eyes and face pale as a ghost.

“…Oh, one more thing…!” Yuichiro shrugged off his haori and held it out to his twin.

“Huh? What are you…?”

“If you get scared tomorrow, you can wear this. It’ll shield you from the sun, and…” Yuichiro suddenly hesitated, his face turning red. “…and, well, it has my scent, so I thought…”

But Muichiro understood. He took the haori and put it on. It was warm, and did indeed smell like his brother. “…Thank you, Yui.”

He moved to give it back, but Yuichiro stopped him. “Just keep it for now. You’re soaking wet. Were you just standing out in the rain this whole time or what?”

Muichiro chuckled. “Yeah, you got me.”

Yuichiro shook his head. “You’re lucky demons can’t catch colds.”

Muichiro laughed lightly. Truthfully, he would happily deal with a cold if it meant being able to walk in the sun again. But it was as his brother said; they would make it happen together. One day.

As long as he had Yuichiro by his side, he would be okay.

Chapter Text

Yuichiro was proud of his brother. Well, he was always proud of him, but lately he had reason to feel especially proud. Muichiro had been making great strides with going outside during the daytime again. Holding onto his twin’s haori helped him to get through most trips, and with time, traveling in the sunlight became easier and easier. With each successful mission, they were returning to a sense of normalcy.

Another night passed, and Yuichiro was heading to the Ubuyashiki Estate to deliver their latest results. The demon had been killed, but its dying words suggested it was working under orders from another demon. Since they were close to the estate, Yuichiro decided he could report his findings to the Master and ask for further investigation in person. And it would be a good chance to see the Ubuyashikis again, which was always enjoyable.

As the Mist Hashira walked onto the Ubuyashiki Estate grounds, however, he spotted a familiar face leaving through the gates. “Kyojuro?”

The Flame Hashira was unmistakable in his fiery attire. He looked up, his contemplative expression changing to a bright smile. “Yuichiro, my boy!”

“What are you doing here?” Yuichiro tilted his head.

“The Master has assigned me a new mission, and I must leave soon if I am to make it on time!” Kyojuro explained. “Ah, but I still have time to talk! How have you and your brother been?”

“We’re doing fine,” Yuichiro answered. “Muichiro’s sleeping right now, but he’s doing better with being out during the day.”

“I’m glad to hear it! And how are you faring?”

“I’m doing better, too; the nightmares are less frequent. We’re being a little more careful now, and seeing him alive puts me at ease. So, I’m okay.”

He still worried for Muichiro, but that was just his natural duty as an older brother. Kyojuro understood that, which was why he could be honest with him. The Flame Hashira grinned proudly and nodded. “I’m very pleased to hear about your progress! I know how you feel as an older brother, but I’m glad you’re giving Muichiro the chance to grow! Perhaps you could pay Senjuro a visit? He might find your story inspiring!”

Kyojuro broke into a laugh, but Yuichiro wasn’t so keen on that. He found the younger Rengoku brother to be too meek and soft-spoken for his liking. It got on his nerves, and made him feel like a villain for getting impatient with the boy. But he didn’t want to admit that, so he decided to change the subject instead.

“So, what kind of mission are you going on?”

“Ah, that! There have been increasing reports of civilian disappearances aboard the Mugen Train. As of this time, over forty people have gone missing. It must be the work of a demon!”

“So they’re sending you alone?” Yuichiro knew full well how capable Kyojuro was, but the idea still made him hesitant. If one demon was responsible for the disappearances of over forty people, it could be a Lower Moon or, as unlikely as it was, even an Upper Moon.

Kyojuro shook his head. “Not at all! Young Kamado, as well as his sister and two friends, will be accompanying me as well!”

“Huh? But Tanjiro is Tomioka’s tsugoku, right?”

“Officially, yes, but Kamado has expressed an interest in Flame Breathing. Thus, the Master is allowing him to accompany me on this mission.”

“I see… hold on, who are these other friends of Tanjiro’s?”

“They are two Mizunoto who were on the Mount Natagamo mission! You may have seen them around the Butterfly Estate! Agatsuma has yellow hair and a yellow haori, while Hashibira wears a boar head mask!”

“…What?!” Yuichiro’s eyes went wide as realization hit him like a brick. He knew exactly who Kyojuro was talking about. Tanjiro had befriended the two boys during his recovery, and they worked well together in training. But from his brief interactions with them, he knew Agatsuma was a cowardly pervert who screamed far too much (and who had once mistaken him for a girl), while Hashibira was a half-feral lunatic who wore a boar’s head as a mask.

In other words, they were total idiots.

“You can’t be serious!” he continued, unable to believe what he was hearing. “Tanjiro is one thing, but those losers?! Why would the Master send them?!”

“Do not be so quick to dismiss them,” Kyojuro chuckled. “Kocho tells me that they’ve mastered Total Concentration Breathing Constant! Furthermore, Kocho herself recommended to the Master that they accompany me!”

“Why the hell would she do that?” Yuichiro asked. But he soon decided that wasn’t important. The issue was that Kyojuro’s “backup” was a bunch of unproven newbies. Tanjiro was the only one he had faith in; he didn’t trust the blond idiot or the boar boy to protect a henhouse, let alone human lives.

Kyojuro laughed and clapped a hand on his shoulder. “Do not fear! I am more than capable of handling this mission on my own; the backup is simply extra assurance!”

“Then take us with you!” Yuichiro shoved his hand off and glared. “Better safe than sorry, right? Muichiro and I will be way more useful than those guys!”

“That is not possible. You two have your own territory to protect, and I cannot take you away from that.” Kyojuro was still smiling, but his eyes were softer. “Do not worry so much! Focus on your own duties! When I return, we’ll have a meal at my estate to celebrate!”

Despite his insistence, Yuichiro still worried. But he knew he couldn’t stop Kyojuro from doing what he wanted, so he reluctantly backed down. “…Fine. But you’ve promised us a meal now, so you better keep that promise!”

“Of course!” Kyojuro laughed. “But I must be going if I am to make it to the train on time. Farewell!”

He walked off, and Yuichiro watched him go. Why was he so concerned, anyway? Maybe Muichiro’s brush with death had left his nerves on edge and made him more aware of how easily any of them could die. But he reminded himself that Kyojuro was strong, and that whatever demon was threatening the train, he could handle it.

He turned around and headed into the estate to greet the Master.

—

The meeting with the Master went well. Muichiro woke up to say hi, and Amane and her daughters even packed some snacks for the twins to take with them. As Yuichiro walked towards the gates to leave, a voice called out to him.

“Heyyy, Tokito!”

Yuichiro looked up, and the harsh light of the afternoon sun flashed directly in his face. “Gah! Fuck!”

“Language!” Muichiro shouted.

“Shut up! And you still can’t-”

“Hey Tokito, don’t ignore me!” Yuichiro stopped and squinted as Uzui walked up to him. His diamond-studded headband shined, blinding in the sunlight. “That’s so unflashy!”

“Tengen…” Yuichiro groaned. “What are you doing here?”

“Reporting to the Master. I… gotta report a failure on my part.” Uzui let out a disappointed sigh. “The Lower Moon I was investigating seems to have disappeared off the face of the earth. Don't know if someone else killed it first, but it’s gone. Weird, huh?”

Yuichiro didn’t say it aloud, but he agreed that it was strange. As annoying as he found Uzui, he was a skilled shinobi with excellent tracking skills, so for him to completely lose track of a demon was unusual. Now that he thought about it, the last he’d heard of a Lower Moon was the one Tanjiro fought on Mount Natagumo, more than two months ago.

“Buuut, enough about that! I’m glad I caught you two!” Uzui suddenly declared, startling Yuichiro out of his thoughts.

“Huh? Why?”

“Why? Well, today’s your lucky day! The guys and I are having a night out on the town tonight, and you’re invited! And it’s all on me, so feel free to go wild and be as flashy as possible!”

“…Huh?” Yuichiro said again, still lost. “Invited? Like, to a party?”

“Something like that! We’re gonna enjoy the nightlife and eat and drink until we pass out!”

Yuichiro wasn’t sure about this; partying with Uzui of all people seemed like a recipe for disaster. “Who else is gonna be there?”

“Besides you two and me, Iguro and Shinazugawa are coming too.”

“Shinazugawa’s gonna be there?” Yuichiro sneered and turned up his nose. “Pass.”

“Aw come on, don’t be like that! It’ll be great!” Tengen patted him on the shoulder. “We’ll have lots of good food, get drunk-”

“We’re fourteen.”

“We’ll get you some milk then.”

“I said fourteen, not four!”

“It’s a Hashira guy’s night out, kid, opportunities like this don’t happen often!” Tengen shook him around. “You gotta come!”

“Are Himejima and Tomioka coming?” he asked as he shoved the Hashira’s hand off and steadied himself.

“Nah, Himejima’s away on a mission, and I already asked Tomioka, but he just walked off. So unflashy.”

“Wait, so why does he get to refuse but I don’t?!”

“Because I can do this to you.” Tengen suddenly wrapped his muscular arm around Yuichiro’s waist and hoisted him into the air. He twisted him around so he was hanging off his shoulder.

“What the hell?! Let go of me, you bastard!” Yuichiro kicked and flailed, but Tengen just laughed.

“You gotta get some meat on your bones, kid. It’s like you weigh nothing at all!”

“Not all of us can be built like gorillas, you gaudy ape!”

“Gaudy? Man, you really know how to hit a guy where it hurts…”

“I’ll hit you where it hurts, you-!”

—

Inside his basket, Muichiro silently listened to the argument raging outside. He sighed. Uzui was able to anger his twin without even trying, and Yuichiro was too easily riled up. They made an unsuitable pair.

Muichiro wrapped his brother’s haori around himself and let the mist rise in his mind. He felt the warm sunlight just outside his basket and wanted a distraction from it. The yelling faded out, granting him a measure of peace.

Until the basket jumped unexpectedly, knocking the demon from his reverie. He heard Uzui laugh as Yuichiro cursed the Sound Hashira’s bloodline.

Muichiro sighed again. This was going to be a long afternoon.

—

Yuichiro wouldn’t stop scowling as he followed Uzui through the crowded streets. Most people walking by noticed his sour expression and gave him a wide berth, but there were still too many people out for his liking. And despite the sun having just set, he’d managed to pass by three men who were so drunk they could barely stay on their feet. He hated it.

In contrast, Muichiro walked cheerfully beside him, happy to be out of the basket at long last. He still wore Yuichiro’s haori, and his human-looking eyes jumped around, taking in the evening revelry.

Uzui was out of uniform, dressed in a casual but still clearly expensive red kimono. He’d forced Yuichiro to change clothes as well, putting him in a blue and white striped yukata and dark blue hakama pants. Yuichiro questioned why Uzui even had clothes in his size at his estate in the first place. Muichiro didn't wear human clothing, but he had shifted his outfit to a pale blue and white striped yukata with a misty teal hakama to match his twin.

“Are you going to give that back?” Yuichiro grumbled as they walked, eyeing his haori. “It’s not daytime anymore.”

“Aw, but I like it!” Muichiro grinned. “I want one!”

“Make your own, then! That one’s mine!” Yuichiro tried to grab it, but Muichiro laughed and danced out of his reach. Before he could chase after him, Uzui grabbed his arm and pulled him forward.

“Stay close, kid! Don’t wanna lose ya!” Yuichiro growled and seriously considered biting his hand to make him let go before Uzui did so all on his own. “Hey guys, over here!”

He waved at something ahead, and Yuichiro followed to see Obanai and Sanemi walking through the crowd. His mood soured even further at the sight of the Wind Hashira. Muichiro came close and stood slightly behind him as he directed his own glare towards Shinazugawa.

As they walked up, he saw the two were dressed casually as well, Obanai in a dark blue kimono while Sanemi wore a green yukata and tan hakama. Sanemi’s face twisted with annoyance at the sight of the twins. “Seriously? You brought the brats? They’re not even old enough to drink!”

“So what? A little alcohol’s no big deal! It’ll be a learning experience!” Uzui waved him off.

But Yuichiro was quick to shoot him down. “Like hell we’re drinking any of that crap!” He’d seen what alcohol did to people and he wanted nothing to do with that.

“We should get going before all the shops fill up,” Obanai raised his soft voice to be heard over the crowd.

“Right you are, and I know just the place to start! Come on, kid!” Uzui grabbed Yuichiro’s arm and dragged him along again, leaving Muichiro to look awkwardly between the other two Hashira before running after him. Sanemi and Obanai exchanged exasperated looks, then followed behind.

Uzui led them to a ramen shop, and the smell of freshly prepared noodles and broth helped Yuichiro to forget some of his irritation. They managed to grab five seats together, Uzui at the rightmost end and Obanai at the left end, with the twins and Sanemi seated in the middle. Uzui ordered for all of them, and soon three bowls of ramen and two plates of sashimi, along with quite a few bottles of sake (and milk, to Yuichiro’s annoyance), were spread out before them.

“You gonna eat?” Sanemi asked Obanai between bites of noodles.

The Snake Hashira placed a few pieces of fish on his plate. “I’m not hungry, but if I decide to drink, I’ll eat something.”

Sanemi nodded in understanding and returned to his food. On the other side, Uzui poured himself a cup of sake while Muichiro observed curiously. He watched the Sound Hashira down the cup in one gulp, then turned to his twin.

“Nii-san-”

“No.”

Muichiro’s hopeful expression turned into a pout. “Why not? It’s not like it’ll hurt me.”

“Can demons even get drunk?” Obanai asked. Sanemi shrugged.

“I don’t know, and I’m not about to find out!” Yuichiro put his foot down. “No drinking, Mui, period. And if you try anything-!” He directed a scathing glare at Uzui, who raised his hands in the air.

“Hey, relax! What kinda guy do you take me for?”

“An irresponsible, idiotic, oaf-”

“Nii-san, please…!” Muichiro intervened, frantic to stop a fight from breaking out. “We’re here to have fun, remember?”

He held out a piece of tuna to his brother, who sighed and accepted the peace offering. “Fine, but Mui, don’t listen to a word that guy says.”

“Yeah, yeah…”

“Well, so much for that,” Uzui chuckled. “But I gotta say, kiddo, I’m glad you finally figured out the shapeshifting thing so we can hang out like this!”

Muichiro put on a smile that didn’t reach his eyes. “Yeah, me too. People are less scared of me this way.”

Yuichiro narrowed his eyes and was about to say something when he heard Sanemi scoff. “What? You got something to say?”

Sanemi matched his annoyed glare with one of his own. He leaned back and put his hands behind his head. “Yeah, I do. What are you being all overprotective for? So what if he wants to drink? He’s a demon, let him.”

Yuichiro blinked, then set down his chopsticks and turned to fully face the Wind Hashira. “Excuse me? It’s not being overprotective; it’s common sense! He’s too young to drink! Would you let your little brother drink knowing that he’s too young to handle it?”

“Tch,” Sanemi growled and averted his gaze. He grabbed his sake cup and took a sip. “What does it matter what I would do? I don’t have any brothers anymore; you know that.”

Yuichiro almost backed down at that. He did know that Sanemi had lost his little siblings, and no good would come of antagonizing him for it. And even though he was confident he could put up a better fight than when he first became a Hashira, he had told Muichiro he wouldn’t get into a brawl for no reason. But he couldn't just say nothing; his pride wouldn't allow it.

“Hmph… well, I do have my brother, and I’m going to be a good role model for him.”

Sanemi was halfway through a gulp of sake when he suddenly choked on it. He avoided spitting it out and swallowed it down with some difficulty, but once he recovered, he started grinning. “You? A good role model?”

“Yeah…?”

“Tokito, you swear almost as much as I do. You hold grudges, and you’re rude for no reason. The fact that your brother turned out as good as he did with you as his hero is a fucking miracle.”

“You…!” He stopped, something Sanemi said catching up to him. Yuichiro leaned in and whispered, “He thinks I’m his hero?”

“Duh,” Sanemi rolled his eyes. “The kid looks up to you like you’re the goddamn sun.”

Yuichiro wondered how apt that comparison was, given recent experiences with the sun. But hearing someone else say that Muichiro looked up to him left him a little self-conscious, but also giddy-feeling.

On Sanemi’s other side, Kaburamaru lifted his head and looked at something down the table. Obanai also looked that way, his eyes going wide before glancing at Yuichiro. But the older twin didn’t notice as he grinned smugly at the Wind Hashira. “See? Then I must be a good role model, after all.”

“Hardly. Didn’t you two live in the middle of nowhere? You were probably his only option.”

Okay, screw his promise to Muichiro; this guy needed another broken nose. “You wanna fight, asshole?”

Obanai started to sweat all of a sudden. Even Kaburamaru looked nervous.

“Oh? You really think that’s a good idea? I kicked your ass last time, remember?”

“I’ve been training, and I’m bigger and taller now. This time I’ll-” he stopped as he finally noticed Obanai and his snake silently and frantically shaking their heads towards him. “What are-”

Muichiro suddenly started coughing violently. A sake cup flew out of his grip, sailed across the room, and smashed to pieces against a wall. Uzui burst out into raucous laughter, heedless of the glares the store owner and multiple patrons were shooting his way.

“S-So… b-bitter…!” Muichiro gagged with tears in his eyes. Even worse, his eyes had reverted back to normal and were glowing brighter than usual. Uzui’s laughter turned to panic, and he flailed around before slapping his hands over Muichiro’s face to keep anyone from noticing. The younger Mist Hashira yelled out in bewilderment and tried to push his hands away, almost falling off his chair in the process.

“What the hell?!” Yuichiro watched the chaos before him in disbelief. “Are you kidding me, Muichiro?! What did I just say?!”

“I-I’m s-sor…!” Muichiro was sobbing in between coughs, making his words near unintelligible. Yuichiro couldn’t help but wince; even compared to other human foods, Muichiro was not handling the sake well. He was torn between sympathy for his twin and anger for not listening to him, so he directed that anger towards Uzui instead.

“You gaudy bastard, why did you let him drink it?!”

“I thought it’d be funny,” Uzui shrugged, completely unrepentant. “And I was right! That was one flashy reaction!”

“How much did you give him?”

“Just a cup. But man, you should have seen it! Kid downed that whole thing in one gulp!”

“You goddamn-!”

Finally, Sanemi couldn’t hold his laughter anymore. He started cackling like a madman, redirecting Yuichiro’s ire towards him once again.

“You’re involved in this, aren’t you?!” he yelled. “You distracted me so I wouldn’t notice what the sound bastard was doing!”

Sanemi’s laughter quickly stopped, his usual glare returning to his face. “Please, like I’d involve myself in any of Tengen’s stupid pranks. I’m laughing because it’s fucking funny. Genya reacted the same way when he first tried alcohol. Well, maybe not as bad, but-”

“Huh? Who’s Genya?”

Sanemi stopped talking, his face and body going tense. After a long while, he finally spoke. “…No one. Forget it.”

Muichiro finally quieted down at that point. Uzui lifted his hands and gestured to his eyes, and the young demon blinked before opening human teal irises. He looked ill as he grabbed a salmon and put it in his mouth, only to look even more miserable after swallowing. “I can still taste it…!”

“It’ll go away, don’t worry,” Uzui chuckled. “Anyway, since your brother got his first taste of alcohol, you might as well try it yourself, eh Tokito?”

Yuichiro said nothing, appalled at his brazen offer. Was Uzui completely lacking in shame? Admittedly, a traitorous part of him was curious, if only to see what awful taste could make his brother react so violently. But he shoved that curiosity into the back of his mind where it belonged. There was no way he was trying that stuff!

“Ah, don’t waste your breath, Tengen,” Sanemi chuckled. “I don’t think the brat even knows how to have fun.”

“Huh? What’s that supposed to mean?”

“What do you think? It means you’re a boring rule-stickler who’s too stuck in the mud to just sit back and enjoy life. Do you even have any friends?”

“I…” Yuichiro was honestly a little stunned. He hadn’t expected the discussion to take this kind of turn. “I have friends!”

“Like who? And don’t say your brother.”

“I wasn’t going to!” Yuichiro snapped, even though he didn’t have an answer otherwise. He almost said Kyojuro, but he knew Sanemi would dismiss him on account of the Flame Hashira being much older. But that’s when an answer Sanemi couldn’t deny hit him. “I have Tanjiro!”

“Tanjiro?” Sanemi repeated. “You mean the Kamado brat?”

“Yeah, I do! Tanjiro’s my friend! Him and Nezuko!” There was a time months ago when Yuichiro wouldn’t be caught dead calling Tanjiro his friend, but after so long, he was finally able to say so and mean it. Granted, it was for the purpose of proving Sanemi wrong, but it still counted!

“…Hmph, well, congratulations on finding two whole friends.” Sanemi said mockingly. “Doesn’t change the fact that you’re still boring.”

“I’m not boring…!” Yuichiro growled. This guy was really pissing him off.

“Yeah, you are. The fact that you’re being so difficult is proof of that. Come on, it’s just one drink! Live a little!”

Sanemi practically shoved the sake cup in his hands, which Yuichiro grabbed only to keep it from splashing all over him. “Shove off, I know what you’re doing! You’re trying to goad me into doing what you want, but it’s not going to work! I’m not drinking this crap!”

“Man, you really know how to spoil a good time. I feel sorry for your twin, having such a boring big brother.”

Yuichiro growled and squeezed the sake cup so hard that any more force might shatter it. But then Uzui spoke up. “You know, he’s got a point, Tokito.”

“What the hell are you talking about?” Yuichiro turned towards the Sound Hashira.

“I’m saying that Shinazugawa is right about one thing. You’ve gotta live while you can. You’re fourteen, yeah? Are you gonna wait until you’re an adult to drink? This job is dangerous, you know. You might not live to get that chance.”

A somber silence fell. Yuichiro looked away and stared into the sake cup still clasped in his hands. Uzui was an idiot, but he was right that any mission could be their last. The Shimizu Jima mission had very nearly proven that. And Yuichiro, being so young compared to the other Hashira, was at even greater risk. There was a real chance he could die before ever reaching adulthood.

He tore his eyes away from the sake in the cup and caught a look of distress on Muichiro’s face. His twin must have been thinking the same thing he was. Yuichiro grabbed his hand and squeezed.

“Don’t worry, Muichiro, I don’t plan on dying anytime soon. We still need to make you human again, remember?” Still, he knew that wasn’t a guarantee, so he added, “And besides, no demon’s going to get me when I have you to watch my back, right?”

Muichiro nodded and managed to smile. “Right…!”

“Man, you two are adorable!” Uzui’s laughter ruined the mood instantly, and Yuichiro scowled as he pulled his hand back. He glared into the sake cup as though the liquid had personally offended him. That wasn’t too much of an exaggeration; just the smell of the drink made him queasy. But everyone was looking at him now, even Obanai and Kaburamaru, all waiting to see what he would do.

“…Fine, I’ll try it! But only to get you two jerks off my back!” But as he looked at the sake, Yuichiro found himself hesitating again. Why was it that he could throw himself at man-eating demons without fear but this was too much?

Don’t overthink it. Just drink it all down in one gulp. You’ll barely taste it that way.

Throwing caution to the wind, Yuichiro closed his eyes and brought the cup to his mouth, drinking it all in one motion.

Or at least, he tried to. Because he did taste it; he tasted it very strongly. A harsh, bitter flavor assaulted his tongue, and he immediately felt the urge to spit it out. But Yuichiro refused to show weakness in front of Shinazugawa, and so he choked on his gag reflex and forced the sake down. It burned his throat like fire, and he started coughing up a violent storm as soon as it was all down.

Tengen cheered him on, while Obanai just sighed and put a hand to his face. Muichiro slid his chair closer and patted him on the back as Yuichiro kept coughing. The awful taste lingered in his mouth and made him want to throw up. How the hell did adults drink this stuff and enjoy it?!

Sanemi wasn’t laughing, but when Yuichiro finally looked up, he was met with a smug grin from the Wind Hashira. “So, how was it?”

“How the hell…!” Yuichiro started coughing again. “You actually like this?!”

“It’s an acquired taste,” he said as the Mist Hashira groaned and bent over the counter, clutching his empty cup. Muichiro reached for a piece of tuna as Sanemi patted Yuichiro on the back and added, “Hey, cheer up. At least you proved you're not boring - just gullible!” He chuckled as Yuichiro’s grip on his cup tightened.

“Sanemi-” Obanai started to say.

Yuichiro lifted his head and threw the empty sake cup at Sanemi’s face. Despite literally sitting right next to him, however, the Wind Hashira still dodged the throw, which flew past him and shattered against the back of a man’s head. Silence fell as the large, tattooed man turned around and glared at the group of demon slayers.

No one said anything. Yuichiro pointed at Sanemi, and the Hashira looked at him with an offended expression.

“Oh boy…” Uzui muttered.

—

In the end, they were all kicked out of the shop for property damage and assault. Uzui wasn’t very bothered by it, however, as he led them to an actual bar with musicians playing classical tones as the patrons drank the night away.

Muichiro sat on the sidelines with his brother, watching as Uzui and Sanemi engaged in a drinking contest with some of the other customers. The amount of alcohol they were imbibing was both fascinating and horrifying.

Muichiro couldn’t understand how they were able to drink that stuff so easily. The revolting taste of the sake lingered in his mouth even now. He had half a mind to rip out his tongue and regenerate a new one, but that would be a bad idea for a number of reasons, so he suffered in silence.

Yuichiro, however, made his suffering very noticeable. He groaned miserably as he rested his head on the table.

“Nii-san, are you okay?”

“No. My face feels hot and my head hurts. I don’t like it.” He banged his fist on the table. “This is all that gaudy bastard’s fault. Him and Shinazugawa!”

Muichiro could only smile sympathetically. It seemed there was a good reason why they shouldn’t be drinking alcohol at their age.

“Hey, Tokito,” Obanai called as he walked up and sat down at their table, a plate of takoyaki in his hand. “Have something to eat. Alcohol is harder on an empty stomach.”

Yuichiro groaned again but complied, taking the plate and popping one of the breaded treats in his mouth. As he ate, Muichiro looked at Obanai and asked, “Aren’t you going to join them?”

The Snake Hashira closed his eyes and sighed. “I’d rather not. Alcohol and I don’t get on well. And someone has to keep their wits about them once those two can’t tell up from down.”

A roaring cheer came from the crowd as another patron fell before Uzui’s godly alcohol tolerance. Yuichiro groaned and clutched his head again. “Ugh, it’s too noisy in here. I’m going outside.”

“Oh, I’ll go with you!” Muichiro offered, but Yuichiro shook his head.

“Thanks, but you don’t have to. I’ll be right outside the door. I just need a bit of quiet.” With that, he took the rest of the takoyaki and left the bar. Muichiro watched him go, but another round of cheering drew him back to the main attraction.

“Does it taste better to humans?” he asked Obanai, who shrugged.

“Like Sanemi said, it’s an acquired taste. But all human food tastes awful to you, right?”

Muichiro nodded. “Yeah. It all tastes... I don’t know, rotten? Like it’s been left out to spoil.”

“That must be rough.”

“Yeah, it is.” Muichiro hated not being able to eat human foods. All the new places they’ve visited in their travels, all the new and exciting foods they’ve never seen before, and he couldn’t eat any of it.

“Why do it then?” Obanai asked. “You must have known you couldn’t stomach sake, but you drank it anyway. Why do that to yourself?”

“Why?” Muichiro blinked. His brow furrowed in thought. “Well, people bond over food. They make memories by eating together and sharing their experiences over a good meal. Even if I’m a demon, I still want to be a part of that.”

“Surely you don’t have to hurt yourself to do that, though,” Obanai pointed.

Muichiro shrugged. “It doesn’t hurt me for long, though. I just don’t like sitting around while everyone else is eating and enjoying themselves. It makes me feel separated from everyone. I’ll take a little pain if it helps me feel more human.”

“I see.” Obanai closed his eyes and reopened them, his gaze softening. “That’s understandable; food is indeed important to humans, so it must be hard to be unable to eat like humans do. I’m sorry for bringing it up.”

“No, don’t be sorry! You showed me that I could still eat fish, remember? It’s thanks to you that I’m able to eat with Nii-san and everyone else!” Muichiro smiled, recalling that precious memory.

Underneath his bandages, Obanai’s cheeks turned red. “Ah, right. I’d forgotten about that... Well, I’m glad I could help.”

Kaburamaru flicked his tongue and stuck his head out towards Muichiro. The little demon reached out to stroke the snake’s head. After a few minutes of peacefully ignoring the noise nearby, Yuichiro stormed back in.

“It’s too loud even outside, and there’s drunkard bastards everywhere, too! I can’t fucking take this anymore!”

He immediately collapsed back into his chair, and Muichiro suppressed a guilty laugh. He really did feel bad for his twin. Yuichiro seemed on the verge of tears from frustration, and while Muichiro doubted he was actually drunk off one cup of sake, the alcohol was probably making him feel even more overwhelmed by everything going on. At the same time, though, it was kind of funny, in the way that one laughed at something that was happening to someone else and not them.

“Maybe you two should head home,” Obanai suggested, looking at Yuichiro with sympathy.

“Really? But don’t you need help…?” Muichiro looked to the drinking contest that was still going. How had Uzui not blacked out? Even Sanemi was face down on the table by now.

Obanai shook his head. “I can handle these two on my own. I’ve done it before. Go and get some rest.”

Muichiro nodded and gave him his thanks before tapping Yuichiro on the shoulder. “Nii-san, it’s time to go.”

Yuichiro groaned miserably and slowly stood up while clutching his head. They started heading towards the door when the older twin suddenly stopped.

“Nii-san?” Muichiro looked at him, confused.

It was several seconds before Yuichiro spoke. “…We should go out the back.”

“Huh? Why?”

“I… might have punched some guy out cold and pissed off all his friends out there.”

“…Huh?!”

—

The morning after was a beautiful day with a clear sky. Muichiro had suggested they do something outside, and Yuichiro had no objections. He was glad that his twin felt comfortable enough to be out of the basket during the day again. And he needed a quiet break after the chaos of last night.

Of course, they still needed somewhere with shade, so they were currently wandering through a dense bamboo forest located a couple hours from their estate. Yuichiro had packed food for himself, and he would have liked the idea of having a picnic with his brother, just the two of them. But that was another thing that would have to wait until Muichiro was human again.

Even if they couldn’t eat together, though, he still appreciated having this quiet time where it was just him and his brother. Eventually, he found a densely shaded spot where Muichiro would still have some room to move around, and set the basket down. He tapped on the lid and sat down to eat his early lunch as Muichiro poked his head out. Deeming it safe, he hopped out and sat next to him.

“How are you doing?” Yuichiro asked.

Muichiro smiled. “I’m doing fine. There’s enough shade here that I’m not worried.” After a moment, he asked. “Do you want your haori back?”

“You can keep it for now. I’ll take it back later,” he shrugged.

“Last night was fun, wasn’t it?”

Yuichiro’s mood immediately soured. “Hmph. Hardly.”

“Well, I thought it was fun.”

“Of course you did. You didn’t throw up when we got home.”

Muichiro laughed and slid closer to him as Yuichiro took out his bento to eat. The younger twin leaned his head on his brother’s shoulder, looking peaceful. He closed his eyes, but he wasn’t sleeping, just listening to the sounds around them. The faint buzzing of insects and moving water from a nearby stream were soothing to both twins.

“This is nice…”

“Mm-hm,” Yuichiro nodded, his mouth full. These quiet moments, where it was just the two of them enjoying the beauty of nature, were truly precious.

But the peace didn’t last. A flap of wings came from overhead, and Yuichiro looked up to see Ginko flying towards them. Muichiro reluctantly lifted his head, though his mood improved slightly upon seeing the crow.

“What now? Another mission?” Yuichiro muttered.

But then Ginko landed before them, and the distraught look on her face told him immediately that this was not a mission. Something had happened. And Ginko’s next words confirmed that.

“Kyojuro Rengoku has died! He fought against Upper Moon Three and died!”

Yuichiro felt the world around him grind to a halt. A sudden chill swept over him in spite of the warm weather. Muichiro gasped, but all Yuichiro could utter was a quiet “Huh…?”

Kyojuro Rengoku… died?

No, that couldn’t be right. Kyojuro was one of the strongest people he knew. He was a Hashira, a true chosen one. He couldn’t just die…!

But, Ginko wouldn’t lie. Not about this. Slowly, her words sunk in.

Kyojuro…

Kyojuro Rengoku was dead.

“When I return, we’ll have a meal at my estate to celebrate!”

That would never happen.

“Yui…?”

Muichiro’s voice snapped him back to reality. He looked at his little brother’ face, tears gathering in his eyes as he sniffled and tried not to cry. His eyes seemed to glaze over, growing foggier by the second. A chill ran down Yuichiro’s spine and he reached out, holding his hands tight and giving Muichiro something to ground himself with.

“Hey, it’s okay. You don’t have to hide how you feel. It’s okay to feel sad,” he said quietly, but even those words sounded too loud to his ears right now.

Muichiro nodded slowly. His tears started to run down his cheeks. “But, aren’t you sad, too…?”

Yuichiro didn’t answer. He wanted to be sad. Kyojuro had done so much for them. Without him, neither of them would be here right now. He felt tears of his own building, but they didn’t fall. He wanted to feel sad, but above all, there was a vile, ugly feeling in his heart. One of bitterness and betrayal. One of anger.

But the feeling of being lied to and having his heart broken was nothing new.

“Don’t worry about me. Take care of your brother. I’ll be back when I’ve found the herbs.”

In the end, it was just one more empty promise.

Chapter Text

Yuichiro watched as Muichiro lit the incense in front of Kyojuro’s grave. The young demon had his eyes closed in a silent prayer. His older brother stood behind him, eyes tracing the smoke as it curled and weaved through the night air.

The funeral for Kyojuro Rengoku, the Flame Hashira, was a short and somber affair. Death was all too common amongst the demon slayers, and even for a Hashira, duty could not wait. Yuichiro scarcely remembered anything of the funeral itself. His mind had been far away at the time, lost in memories, while his heart drowned in a torrent of emotions he didn’t have the strength to identify. Even now, all he could be sure of was a feeling of bitterness, of indignation.

How dare he die, when he promised to come back? How dare he leave them behind?

But this was a time for remembrance, and so he swallowed his bitterness and held his tongue. Soon, Muichiro finished his prayer and stood up to face his twin. “Do you want to say anything?”

He had a soft smile on his face, quietly encouraging him. Yuichiro looked down at the stick of incense in his hand, gripped so hard that it was in danger of breaking in two. He was about to speak when a timid voice beat him to it.

“Um… do you two want some tea?” Senjuro walked up to them with a tray in his hands.

Muichiro smiled gratefully but declined. It wouldn’t be appropriate for him to try choking down tea in front of the Rengoku family’s gravesite. Yuichiro just shook his head and said, “No thanks.”

Senjuro nodded and looked away. “T-Thank you for coming to visit. We really appreciate it.”

Yuichiro questioned that. It was obvious how nervous Senjuro was, and the most they had seen of his father, Shinjuro, was the old man giving them a dismissive glare and scoff before retreating into the house.

“Um, will you-”

“No, we were actually just about to leave,” Yuichiro interrupted him. He wasn’t in any mood to deal with the younger Rengoku’s timidity tonight. “Come on, Muichiro.”

“Huh? But…” Muichiro started, but the stern look his twin gave him quieted him instantly. He nodded. “…Okay.”

They left the Rengoku Estate quickly, and Yuichiro didn’t relax until they were out of Senjuro’s sight. He let out a sigh and loosened the death grip he had on the unused incense stick.

“…Nii-san, are you okay?” Muichiro ventured, knowing he wasn’t but having no other way to broach the subject.

“…I’m sorry, Mui. I’m not in the mood to talk about it.” He didn’t even know what he would say. The words that came to mind were too cruel to speak of the deceased.

Muichiro nodded and walked closer to him, brushing their shoulders together. “It’s okay to miss him. I miss him too.”

If only it were that simple. Yuichiro knew he could confide in Muichiro about anything, but some things were better left unsaid. He didn’t want to burden his twin with his uglier feelings. Better for him to just think that he missed Kyojuro and nothing more.

“…Muichiro, will you spar with me when we get home?” Muichiro looked at him, and he elaborated, “Another Upper Moon has shown itself, and we can’t afford to be complacent anymore. We need to be stronger.” And though it went unsaid, he needed the distraction from his thoughts and emotions.

His twin glanced away, looking guilty, before he turned back and put on a smile. “Of course. Whatever you need, I’ll be here for you.”

Yuichiro smiled back. He was truly lucky to have Muichiro by his side.

—

Four months passed. The Upper Moon that killed Kyojuro hadn’t shown its face since. But another one did.

The news of Upper Moon Six’s defeat at the hands of Uzui Tengen and three lower-rank slayers spread like wildfire amongst the Demon Slayer Corps. It came at the cost of the Sound Hashira’s eye and hand, forcing him into retirement, but an Upper Moon hadn’t been killed in over a century. This was big, a change that surely heralded more to come.

And at the center of it seemed to be one Tanjiro Kamado. He was there for Kyojuro’s death at the hands of Upper Moon Three, and he had been one of the slayers who killed Upper Moon Six. Yuichiro wanted to ask him about it, but the boy had been in a coma ever since that battle, almost two months ago.

Yuichiro regretted the time he spent avoiding Tanjiro before he left for the mission with Uzui. He just couldn’t handle being around him, knowing that Tanjiro had accompanied Kyojuro on that fatal mission, that he’d been the one to hear the Flame Hashira’s last words. And he couldn’t help but think about how things could have been different, if only he and Muichiro had gone on that train instead. But now Yuichiro just wanted Tanjiro to wake up.

The two Mist Hashira were spending their time in between missions at the Butterfly Estate, a frequent occurrence as of late. Muichiro was teaching Nezuko more sword techniques, to give the young demon something to distract from her worries. Though somewhat clumsy, and unable to grasp Total Concentration Breathing no matter how Muichiro tried to teach her, she was improving in the forms. Yuichiro watched idly from the sidelines. He was just about to get up and find a quiet place to train on his own when someone called to him. “Yuichiro?”

The boy looked up to see Shinobu approaching. She looked out at the two demons training in the courtyard with a smile on her face. Yuichiro shifted to make room even though it wasn’t necessary, but the Insect Hashira shook her head. “Thank you, but I’m afraid I can’t stay long.”

Yuichiro nodded in understanding. “How have you been? We haven’t seen you in a while…”

“Yes, that’s true. You two come over here quite a bit, but lately we always seem to miss each other,” Shinobu agreed. “My work has kept me busy, but I’ve been well. And I think I should be asking how you’ve been.”

“Me? Why would you be worried about me?” Yuichiro raised an eyebrow, confused and slightly offended. “I’m fine. There’s nothing to worry about.”

“I see…” It was clear she didn’t believe him, but she chose not to pursue the matter. Instead, she said, “Yuichiro, I have a favor to ask.”

A favor? He looked at her curiously.

“I’m leaving for a mission tomorrow night, and I would like for you and Muichiro to join me.”

“Us? What about Kanao?”

Shinobu shook her head. “I’ve already sent Kanao to handle another mission. And… this isn’t something I want her involved in. I can give you the details later, if you agree. Please consider it. I would very much appreciate your help.”

Yuichiro raised an eyebrow. While Shinobu was usually polite, she didn’t usually sound this timid. Like she was pleading for their help. And not wanting her own tsugoku involved… she was hiding something.

But he had known Shinobu for a long time now. He knew how dedicated she was to her responsibilities, and to her family and friends. She must have her reasons to be so secretive. “There’s no need to act so demure; it doesn’t suit you. If you need help, then we’ll help you.”

Shinobu’s smile turned more genuine. “Thank you, Yuichiro.”

“Oh, Shinobu!” Muichiro’s voice called out, the young demon only just taking notice of her. He ran up with Nezuko close behind, a grin on his face. “It’s good to see you again!”

“And you as well, Muichiro.”

“What are you two talking about?”

“We’re talking about a new mission,” Yuichiro answered. “We’re going with Shinobu to…”

He realized he still didn’t know anything about this mission, and turned to the older girl for answers. Shinobu giggled.

“Of course, I should explain, shouldn’t I? We’re going to Shibuya.”

—

Yuichiro didn’t often visit the big city for many reasons. Growing up in the mountains with only his family for company, he preferred quiet places with a lot of nature and very few people. The big city was none of those things. But a promise was a promise, so he and Muichiro were now making their way through the crowded streets of Shibuya in the morning, looking for the building Shinobu instructed them to meet up at.

They were looking for some sort of hotel, but despite the map he was carrying, Yuichiro was completely lost. The city was just too big, and the morning rush meant people were constantly walking past or even pushing him out of the way. It took all his self-restraint to not verbally rip into these people, and his mood was souring by the second.

“Maybe we should ask someone for help…” Muichiro suggested from inside the basket. Yuichiro could barely hear him over all the noise.

But Yuichiro was not ready to give up yet. As stupid as it sounded, he didn’t want to admit the city had bested him by asking for directions. “We don’t need anyone’s help. We can find it on our own.”

“We’ve been wandering around for an hour, though. At least stop and get something to eat since you didn’t do that before we left.”

“I’m not hungry, so I don’t need…” Yuichiro trailed off as a strong scent hit his nose. It was sweet, bringing to mind fresh-baked desserts. He turned towards where the smell was coming from, and indeed, a sweets shop laid just a little ways ahead, its entrance crowded with eager customers. As he stared, his stomach growled, and Muichiro burst into laughter inside the basket.

Yuichiro blushed and stomped towards the sweets shop. “Fine, we’ll take a break!”

The line moved quickly despite the large crowd, and soon Yuichiro stepped inside the shop. The inside was surprisingly dim, but the smell was more mouthwatering than ever. Desserts and candies filled the display counter and Yuichiro pondered what to get. Though it was early in the day, the mitarashi dango called to him, and he knew he’d end up caving even as he scanned the other items. But he should probably get something for Shinobu, too. He wasn’t entirely sure what she’d like, though, and the line behind him was only getting longer, so he decided to play it safe with some strawberry mochi.

Yuichiro paid and rushed to leave the crowded shop, only to nearly run head-first into one of the workers. “Woah, slow down! What’s the rush?”

Yuichiro looked up at a girl around Shinobu’s age, with black hair tied in a bun and wearing a flowery red kimono. Her green eyes looked amused, which only made the Mist Hashira feel more annoyed. “Sorry for running into you, but I’m in a hurry.”

“Is that so? Are you late for school?”

School? “N-No, I’m-”

“Oh, I get it! You’re skipping!” the girl chuckled. “Well, I know how kids your age are! I won’t say anything!”

“Wait, I’m not-”

“Anyway, before you go, would you like to try one of our free mochi samples?”

She held out a tray, and Yuichiro looked at the pale purple desserts stacked on it. He shrugged and grabbed one, folding it up in its paper wrap and putting it in his pocket for later. “Um, thanks…”

“Thank you! Have fun skipping school!”

“I’m not…!” Yuichiro bit his tongue and turned away. There was no point in wasting his breath arguing. He probably did look like he belonged in school, wearing the yukata and hakama Uzui had gifted him months ago instead of his usual uniform. But Shinobu had insisted they dress out of uniform for this mission. He grumbled to himself and walked out of the shop, ready to go look for the hotel once more.

“Yoohoo! Yuichiro! Over here!”

Shinobu’s voice was like an angel sent from Heaven. Yuichiro breathed a sigh of relief, grateful that he wouldn’t have to sacrifice his dignity for directions to the hotel after all.

“Shinobu,” he nodded as the Insect Hashira walked up to him. “You look… pretty.”

“Oh, thank you! You look handsome as well!” Shinobu giggled. The Hashira wore a purple knee-length dress and heeled shoes, along with a handbag and hat in place of her butterfly hair clip. It was a stark departure from her usual attire, and Yuichiro had to wonder why. And where was her weapon? Yuichiro kept his sword concealed in his haori, the one part of his uniform he refused to do without, but Shinobu’s clothes wouldn’t hide anything. She was carrying an umbrella even though it wasn’t raining; was it hidden inside? Before he could ask, Shinobu spoke again. “You just came out of that shop, right? I haven’t been there myself yet, but it seems to be popular. Did you get anything?”

Yuichiro nodded and handed her the box with the strawberry mochi. “Yeah. Here, this one’s for you.”

“Oh my, thank you! Let’s eat in the room, okay? Please, follow me.”

Yuichiro complied, and she led the way to the hotel, which turned out to be just around the corner and down the road, to his annoyance. He silently cursed the vast labyrinth of a city while Shinobu brought him to a room on the third floor and opened the door. The inside was distinctly western in style, with two beds, a bathroom, and a large window overlooking the city street below.

Yuichiro set Muichiro’s basket on the floor and closed the curtains, blocking out the sunlight. He sat on the bed closest to the window, and a few seconds later, his twin peeked his head out and then popped out to happily sit beside him. Shinobu sat on the bed across from them and opened up the box of mochi, her eyes lighting up with delight.

“These look lovely! Thank you, Yuichiro!”

Yuichiro kept his expression even, but inwardly, he breathed a sigh of relief that she seemed to like what he picked. “You’re welcome.” He opened up his own box and pulled out a stick of dango, only to see Muichiro looking at him longingly out the corner of his eye. It was then that he remembered the mochi sample in his pocket, and took that out.

“Oh yeah, I forgot about this…” Now that he thought about it, he didn’t even know what flavor it was. Taro, perhaps, to fit the color? But Muichiro’s eyes glowed with excitement, and he plucked the sweet from Yuichiro’s hand.

“Thank you, Nii-san!”

“Hey wait, don’t-”

But Muichiro didn’t listen, as usual, and popped the whole thing in his mouth. Predictably, his face went pale and he started choking a second later. Yuichiro sighed; he understood why Muichiro insisted on doing this to himself over and over again, and he was resigned to just let him ride out the sickness. But seconds passed as his twin continued to try and swallow the small treat, biting back gags and wretches, and slowly his concern grew. He didn’t usually have this much trouble eating human food…

“Muichiro, are you okay?” Shinobu asked, looking quite worried herself.

Despite all the evidence showing otherwise, the younger twin nodded. He finally swallowed it down, but he still looked moments away from throwing it back up. The hotel room was silent but for his labored breathing that soon returned to normal. “I’m… okay.”

“Are you sure?” Yuichiro asked.

“Yeah, my body just didn’t agree with it.”

“That sounds like a warning that maybe you shouldn’t be doing it, then.”

Muichiro laughed sheepishly. “Yeah, you’re probably right. But I’m okay, really! Maybe it was the texture; I did bite down on something crunchy…”

Something crunchy? In mochi? “Gross.”

His brother laughed again, then groaned and clutched at his stomach. He fell back against the pillows and curled up on his side in a sad fetal position. Yuichiro sighed again and looked at Shinobu. “Give him ten minutes, he’ll be fine.”

“I see…” Shinobu still looked worried, but she didn’t comment. “In that case, let’s discuss the details of this mission.”

Yuichiro sat at attention, and Muichiro tried to listen as he moaned in pain. “Now, we’re here to investigate the disappearances that have been going on in this area. So far, there have been fifteen disappearances in the past two months. I believe it to be the work of a demon.”

“What makes you think that it’s a demon and not just some human?” He knew that big cities were full of unsavory people, and these victims could have just run afoul of a human killer or even a gang of criminals before encountering a demon.

“The disappearances are too clean to be the work of a human. There’s no evidence of a struggle, suggesting the victims were caught without a fight. But there’s something else that’s even more suspicious. On the nights of the past disappearances, people have reported peculiar smells around this area.”

“Peculiar smells? Like what?”

“That’s just the thing. Everyone smells something different. The only commonality seems to be that the scent is nostalgic, bringing to mind happier times of whoever smells it.”

That was… interesting. But it also wasn’t much to go off of. “You said you didn’t want Kanao involved in this. Why is that?”

“Ah, that.” Shinobu smiled guiltily. “Well, you got me, though I wasn’t planning on keeping this a secret. But I also believe this demon knows who I am, and that it has a grudge against me.”

That got both twins’ attention; even Muichiro lifted his head up to listen better. Shinobu opened her handbag and pulled out a piece of paper, which she handed to Yuichiro. Muichiro sniffed the air, then immediately balked and buried his face back in the pillow.

Yuichiro could see why; the paper reeked of wisteria. A note was written in delicate handwriting: ‘Come and find me, butterfly’.

Shinobu continued. “This was left at my first hotel room. I don’t know how the writer found out where I was staying, but needless to say, I changed hotels soon after.”

That was more than understandable. Just the thought of a demon knowing where she was staying, possibly even watching her sleep, gave Yuichiro chills. “Is that why you asked for our help?”

“Indeed. If the demon knows who I am, it will be that much more difficult for me to track it down and lure it away from any civilians. In addition, if the strange smells are related to the demon, then Muichiro’s nose will be our best chance of following them.”

Yuichiro looked at his brother, who was still pale and clearly in pain. What the hell was in that mochi? Whatever it was, he hoped it would wear off by nightfall.

“Anyway, there’s not much to be done but wait until tonight to find the demon before it strikes again.” Shinobu continued. “We do have time until then, so feel free to do whatever you want until evening. I’m going to do a little shopping; you’re welcome to join me.”

Yuichiro nodded but didn’t take his eyes off his brother. He couldn’t help but worry; Muichiro’s demon body would break down whatever was affecting him eventually, but he still hated seeing his twin suffer. “Thanks, but I think I’ll stay here until Muichiro feels better.”

“You… you don’t have to do that, Nii-san,” Muichiro muttered, turning his head and cracking open one eye. “I’ll be fine on my own here. You should… go and hang out with Shinobu.”

“Mui, you don’t look good. Someone should-”

“I told you, I’ll be fine. I’m a demon, remember? I wanna rest, anyway. Just… come get me when the sun sets, okay?”

“….Fine. You stay here and sleep it off. We’ll be back before nightfall.”

Muichiro smiled gratefully and closed his eyes. Yuichiro pulled the blanket over him and made sure he was comfortable before following Shinobu out.

Muichiro would be okay, he assured himself. He had to be.

—

“Is there anything you want here, Yuichiro?”

Yuichiro followed beside Shinobu as they made their way through Shibuya’s shopping district. Hours had passed, and it was now mid-afternoon. They’d spent the whole time browsing through stores and even a big shopping center, buying supplies to send back to the Butterfly Estate before doing some leisurely shopping for clothes and gifts. There was still a while until sunset, and Yuichiro had to admit that he was getting antsy being away from Muichiro for so long. He distracted himself by listening to Shinobu’s stories, of which she had a lot. Life at the Butterfly Estate had been pretty exciting as of late.

In fact, he was so engrossed in her story that the sudden question didn’t register at first. Then it did, and he quickly shook his head.

“I’m okay. I don’t really need anything.”

“…Well, you’ve just been listening to me go on this whole time without saying much yourself. That’s not very fair; what have you been doing lately?”

“Just the usual. Missions take up most of our time, and when we’re not on missions, we’re training or visiting Nezuko.”

“That’s very kind of you to do that.”

“It’s mostly Muichiro spending time with her,” Yuichiro clarified. Even if he did consider Nezuko a friend, it was hard for him to understand her, so they didn’t hang out much. “I don’t mind, but I wish he wouldn’t neglect his own training so much to do it.”

“Why do you say that?” Shinobu asked.

“Well, it’s obvious, isn’t it? Our enemies are starting to show their true strength. At first it was just Upper Moon One, and he’s… complicated, but now Upper Moons Three and Six showed themselves as well. And only Six, the weakest of them, is dead. We need to start training more seriously, otherwise we’ll get caught unprepared.”

Yuichiro would always remember the cold winter day on which Kokushibo appeared at their home. He was an impossibly strong opponent who he and Muichiro had no chance of defeating back then. If it wasn’t for Gyomei and the rising sun, Yuichiro would have been made a demon as well, both twins forced to serve under Muzan’s will. A fate worse than death.

Even now, he wasn’t sure if they could beat Upper Moon One. He didn’t even know if they could beat Upper Moon Three. Kyojuro couldn’t, and the Flame Hashira had always been stronger than him.

But maybe if we fought together, things could have been different.

“Caught unprepared… are you thinking about Rengoku?”

Shinobu’s question jolted him from his thoughts like a rush of cold water. He stared at her, mouth agape. “What?”

The Insect Hashira smiled sympathetically. “Yuichiro, I’m sure you think you’re good at hiding your feelings, but you’re really not. It’s obvious how upset you’ve been since his death.”

“I’m not- I mean, I’m not any more upset than anyone else is! Kyojuro was friends with everybody!”

“He was, but he was especially close to you and Muichiro. And I know you were close to him,” Shinobu said. “It doesn’t matter what everyone else feels; it matters what you feel. Everyone grieves differently-”

“This has nothing to do with my feelings!” Yuichiro snapped, feeling a defensive anger rise up inside him. “I’m being realistic! Kyojuro was a chosen one, but he still died against Upper Moon Three! That means the rest of us need to get even stronger, and we can’t be making stupid decisions like choosing to go alone on dangerous missions!”

“What do you mean? Rengoku wasn’t alone-”

“Tanjiro and those idiots don’t count! Maybe they’re strong enough now to take on an Upper Moon, but back then, they weren’t! But Muichiro and I could have come instead; I begged Kyojuro to take us instead! But he wouldn’t listen, and now he’s dead because of it!”

Just like Mother. Just like Father. Why didn’t anyone ever listen to him? Just because he was a child, it didn’t mean he was stupid. But the adults in his life just ignored him and made empty promises that they would be okay, so don’t worry…!

Shinobu looked at him sadly. “Yuichiro, I understand what you’re saying, but you shouldn’t blame yourself or Kyojuro. No one knew that the Upper Moon was going to show up. It’s a risk we take with every mission that our next opponent could be too powerful to overcome.”

“But if we were there, he could have lived! We could have held out until sunrise!”

“Forgive me for being blunt, but you don’t know that. You don’t know that it would have turned out any better had you been there.”

“So it’s better that he went without us so that only he had to die?!”

“That’s not what I said. I’m saying it’s not fair to-”

“I don’t care!” Yuichiro yelled, repressed bitterness rising up in full force. “I’m sick of people telling me they’ll be okay and then dying! What good is sacrificing yourself for other people when everyone you leave behind is worse off for it?”

“We’re Hashira, Yuichiro. Our duty requires us to put the lives of others before our own. You, me, Muichiro, Kyojuro… We all accepted that. It’s not fair, but it’s what we chose when we took up this position. Rengoku likely knew he would die, but he fought anyway to protect the people under his care. We have to respect that.”

Her tone was firm yet patient and understanding, and it just pissed Yuichiro off more. “Please, like you’re any better than me. I’ve seen how angry you are when you think no one’s watching. You’re gonna tell me you’re not the least bit mad at Kanae for leaving you behind?”

Shinobu’s eyes went wide, then narrowed. Though her voice was even, an inner anger shined through. “No, I’m not. Because I know it wasn’t her fault, and I couldn’t have stopped it. The only one to blame is the demon that killed her.”

“Well, good on you for accepting how weak you are,” Yuichiro hissed. Shinobu reeled back, the hurt in her eyes evident, but the regret he felt was buried in his mounting anger. He turned away. “I’m done talking about this. Just leave me alone.”

He walked away, and Shinobu didn’t follow him. He felt her eyes on him for a while before he finally got far enough to take a breath. And then his heated anger died down, cold guilt taking its place. Why did he say that? He knew Shinobu wasn’t strong enough to cut a demon’s neck, and though she worked around it, that weakness still haunted her. Why did he think it was in any way okay to mock her about it?

But of course, he knew exactly why. It was because he was angry, and when he got angry, he said hurtful things to people trying to help him. That had never changed, even after all these years.

Yuichiro kept walking. He had no real destination in mind, and decided to just go back to the hotel. He’d left Muichiro alone long enough, and there was no other reason to be out here.

That is, until a familiarly sweet smell drew his attention. There was that sweets shop, the one that gave him the mochi that made Muichiro so sick. Maybe he could find out what was inside of it that would cause that. Even at this time of day, the shop was crowded with customers, and as he waited to go inside, he heard a group of men talking.

“Mmm, do you smell those cakes? Reminds me of home; I can’t wait to get one!”

“Huh? Cakes? Don’t know what you’re smelling, but that’s clearly pie dough baking in there.”

“It’s a bakery, stupid, they sell both. But also, you’re both wrong; that’s the smell of chocolate!”

Yuichiro tilted his head. He sniffed the air, the scent seeming sweet and also savory, like mitarashi dango. Certainly not like any of those other things. Either these guys had no idea what they were talking about, or the smell was different for everyone. Just like the scents surrounding the recent disappearances…

Soon the entrance cleared enough for him to go inside, and almost immediately, he saw a familiar red kimono. The sampler girl turned and spotted him, a smile coming to her face.

“Well, look who’s back! I hope you don’t skip school like this everyday. People will start thinking you’re a delinquent.” She laughed at her own joke. Yuichiro rolled his eyes.

“What was in that mochi sample you gave me this morning?” he asked, very much not in the mood for joking around.

“Hm? Um, let me think… taro, lavender, a hint of wisteria-”

Yuichiro’s eyes went wide. “Wisteria?!” His horrified shout drew more than a few curious stares.

“Um… yeah? Why? Are you allergic? Should I have mentioned that?”

“Yes!”

“Eep! B-But, the amount of wisteria shouldn’t have been harmful to humans… oh, I knew I was forgetting something important!”

Was she serious?! A wisteria mochi?! Yuichiro felt the urge to scream, but yelling at her would do more harm than good. She didn’t make the treats, probably, and Yuichiro himself had just taken the sample with no questions. But how the hell did Muichiro eat wisteria without realizing that something was wrong?!

“What about the crunchy thing inside?” he asked, remembering the other thing Muichiro had mentioned.

“Crunchy? Oh, that must have been the nougat!”

What the hell was a nougat? Was this even still a mochi at this point?

“I’m really, really sorry about this! How about another treat as an apology?” She held out the tray she was carrying. “This one’s toffee with an almond center; nothing else, I promise!”

Yuichiro looked between the girl and the samples warily. He already had his suspicions about this place, and now they had only grown stronger. But maybe these desserts were somehow related to the demon’s activities; in which case, he should take one to examine later. He grabbed a toffee and just held it in his hand.

“Thank you, but I should be going now.”

“Sure, no problem!” The girl just looked relieved that he wasn’t angrier. “Have a nice day!”

Yuichiro didn’t bother with more than a nod. He left the shop and walked until he found a small park without many people around and sat on a shaded bench. He looked at the toffee in his hands. At first glance, it seemed entirely ordinary. But then he pulled it apart, and his eyes narrowed.

“What the…?”

A brown seed rested in the center of the toffee. He pulled it out and turned it over in his palm to examine it. Whatever this was, it was certainly not an almond. It was too big and gnarled. Maybe it was some sort of Blood Demon Art, but if it was, he couldn’t expose it to sunlight before Shinobu had a chance to see it. A new surge of guilt ran through him as he remembered his parting words to her. He would have to apologize for the awful things he said. He just hoped she would be willing to listen.

Just as Yuchiro was thinking of leaving, the seed split open. What-

The seed hissed and sprayed a cloud of gas right in his face. Yuichiro gasped and sputtered, trying to wave it away, only to scream as an agonizing pain shot through his left hand. The seed had sprouted thorny tendrils and burrowed into his palm, rooting itself firmly in his flesh. Ripples of pain ran unceasingly up his arm like nothing he had felt before.

Within seconds, the world began to blur and spin. He couldn’t focus, couldn’t concentrate on anything around him. Everything seemed to move in slow motion. There must have been some sort of poison in the gas, or the seed itself. The noxious scent of the gas turned into something else, something smokey but comforting. It reminded him of a warm fire, reminded him of-

“Young man, are you okay?” A voice broke through the haze. Yuichiro clenched his hand shut and hid it in his sleeve, which only caused more pain to shoot through his arm like lightning. He looked up into the concerned face of an elderly woman. “You look quite pale. Are you sick?”

He heard her words, but they moved like sludge through his brain. His mouth felt dry and he struggled to answer. “N-No, I…”

“Where do you live? I can take you there-”

“No!” The world sped up again, moving too fast this time. Yuichiro shot to his feet and almost tipped over from the sudden dizziness, but he managed to stay standing. “I… I’m fine! I don’t need help…!”

He ran off before the old woman could respond. Normally, he might feel bad for snapping at her, but right now, he just needed to get away. Sights and sounds assaulted his senses, and he retreated into a quiet alley to try to calm down.

Slowly, Yuichiro became able to think again. He gingerly uncurled his hand and tried to grab the part of the seed still exposed, but just touching it sent a horrible wave of pain up his arm. He felt it twitch and dig deeper, causing his fingers to involuntarily close around it, and he couldn’t unclench them again.

Where was Shinobu? If anyone could get it out, it’d be her. But Shinobu wasn’t here. He’d yelled at her, drove her away. He was all alone now, and he had no one to blame for that but himself.

The world was still spinning around him, and a sudden bout of nausea almost had him throwing up his meager breakfast. The smoke smell was all around him, suffocating, disorientating, but he couldn’t help but get pulled into his own thoughts. The smell seemed so familiar. Shinobu had said something about this, right? Peculiar smells that reminded people of the past… but he didn’t have any significant memories of smoke or fire, nothing except…

“Know that, though we may be comrades and equals now, you can always come to me for anything! Whatever you need, you can always count on me to help!”

…Ah. Of all the things to be reminded of… Was it because his argument with Shinobu had brought Kyojuro to the forefront of his mind? Or had the late Hashira always been there, and he’d just tried his hardest to ignore him? To have that wound exploited by the demon he was hunting; what a cruel joke.

“Then take us with you! Better safe than sorry, right? Muichiro and I will be way more helpful than those guys!”

“That is not possible. You two have your own territory to protect, and I cannot take you away from that.”

What a worthless excuse. While Kyojuro was fighting, he and Muichiro had been with the other Hashira, getting drunk and partying without a care in the world. Why didn’t Kyojuro take them with him? They could have… he could have…

Yuichiro started walking. He didn’t know where he was going, nor did he care; he just needed to get away. But the memories wouldn’t leave him alone.

“Do not worry so much! Focus on your own duties! When I return, we’ll have a meal at my estate to celebrate!”

Liar.

The smoke filled his head, blocking out everything else. He couldn’t breathe properly. He couldn’t…

…

“Yuichiro!”

The flapping of wings reached his ears, and suddenly Ginko was in front of him, squawking frantically. Yuichiro blinked and tried to push through the haze in his mind, his eyes drifting to the sky. It was orange; the sun was setting. How long had he been out here? He didn’t recognize his surroundings.

“Yuichiro, look at me! Tell me what’s wrong!” The crow beat her wings in his face to get his attention.

“Ginko… find… find Shinobu…” It was hard to focus. His hand hurt horribly, and the smoke smell still overwhelmed his senses.

“Okay, I will! Wait here, don’t move!” Yuichiro blinked, and when he opened his eyes, Ginko was gone. He was alone again.

The sun was sinking lower, and soon it would be night. He was going to break his promise to Muichiro, wasn’t he? What cruel karma that would be, to get so mad at Kyojuro for lying and then end up doing the same thing. He was sure now the demon was hunting him. If he survived this, he would never leave his twin’s side again.

Sorry, Mui… I hope… you find me first.

—

Muichiro wasn’t sure how much time had passed. It was the afternoon now, maybe? It was hard to tell with the curtains drawn and he didn’t feel like getting up to check. However long it was, it was too long for this sickness to be persisting.

For some cruel, unknown reason, sweets were always hardest for Muichiro to eat. His body just didn’t digest human food, and so it always sat uselessly in his stomach. But this time felt different. Usually human food just made him nauseous, but the mochi was causing him physical pain. He was cold and feverish at the same time, which was strange in and of itself, and it felt like something sharp was digging into his stomach.

This sickness… was the mochi poisoned? But normal human poisons wouldn’t affect him. The only thing that could hurt him would be…

…Oh. Now that he thought about it, he never did ask what was in the mochi. But who would put wisteria in mochi anyway? His body should have broken the poison down by now, but maybe the dessert mixed in was getting in the way?

Whatever the reason, Muichiro needed to get it out of him now. But how? Should he try to throw it up? But before he could try that, a rather… embarrassing memory came to mind. He’d once forced down tea and then transformed into his Haze form, which resulted in a mess on the floor when the undigested tea simply fell out of him. He tried to refrain from transforming after eating following that incident, but maybe…

He willed his cells to split apart, and his body burst into mist. And it worked; the sharp pain disappeared as something dropped onto the bed. He quickly changed back and inspected the mushy but still mostly intact remains of the mochi, noticing something else mixed in, too. A seed of some sort, cracked where he’d bit it, with thorny roots extending from its base.

Muichiro regarded the seed suspiciously and dragged a claw down his palm. Red mist bubbled from the wound, forming a misty snake that opened its jaws and bit down on the seed. Almost immediately, it crumbled and he tasted the faintest hint of a demon’s blood on his tongue.

Muichiro’s eyes widened as realization hit him. The seed was a Blood Demon Art hidden inside the mochi. But the mochi hadn’t been meant for him; it had been given to his brother. He didn’t know what eating the seed would do to a human, but it couldn’t be good.

The young demon rushed to the window and pulled back the curtain. Sunlight spilled into the room, and his anxiety only increased further. It was still daytime; he couldn’t go out. He couldn’t warn Yuichiro and Shinobu of what he discovered.

Muichiro closed the curtain and curled back up on the bed. All he could do now was wait. Wait, and hope that they would come back for him soon.

Chapter Text

Yuichiro didn't know how much time had passed since Ginko left to find help. He sat where she left him, his mind fading in and out of reality, until one time he opened his eyes and realized night had fallen. His hand pulsed painfully and he smelled smoke again, the scent threatening to pull him under once more.

He’d been lost in a haze of fragmented memories, all revolving around the late Flame Hashira. Their first meeting, their first mission, even bits and pieces he’d only heard once like his favorite color - red, of course - filled his head and muddled his mind. At this point, he could barely bring himself to feel angry. He was just tired; he didn’t want to remember any of this. Each unwilling memory only made the loss hurt more.

Yuichiro knew this was the work of a Blood Demon Art. What a cruel joke, taunting him with the very thing he’d spent all this time trying to ignore. Taking mission after mission, training to the point of exhaustion, all to not have to think about the pain he felt remembering that Kyojuro was gone. What a cruel, sick joke. If he found the demon responsible…

…well, in his current state, he doubted he could even wield a sword. Even without the poison, his breathing techniques needed both hands to use properly, and he could barely move his left, only able to open his fist for a second before his fingers locked up again. It occurred to him that the seed was meant to be eaten, and he wondered what it would have done to him if he had.

The wind blew past him, cold and lonely, and the smoke smell grew stronger. Much stronger. He looked up, and though he didn’t see anything, his eyes were drawn in a certain direction.

No, there was something. It was hard to focus, but standing on the other side of the street was a figure with bright orange hair and a fiery cape blowing behind him. Yuichiro’s eyes went wide.

Kyojuro?

The Flame Hashira watched him from afar, not moving or saying anything. Then after several seconds, he simply turned and walked away. Yuichiro’s heart leapt into his throat, a sudden panic overtaking him. His rational mind knew this couldn’t be real. It had to be a trick by the demon. Ginko had told him to stay here!

But…

…but he couldn’t bear to ignore it. The thought of not going after him, of letting him leave again, was unthinkable. The pain in his hand pulsed in time with his quickening heartbeat.

He couldn’t lose sight of him. He couldn’t lose him again.

“Wait! Kyojuro!”

With the smell of smoke guiding him, Yuichiro climbed to his feet and ran after his lost friend.

—

Night fell, and neither Yuichiro nor Shinobu were back yet. Muichiro’s claws were digging holes in the bedsheets as he anxiously peered through the curtains and watched the sun set bit by bit. But it finally dipped below the horizon after what felt like an eternity of waiting, and Muichiro leapt to his feet.

What should he do? He needed to find them! If the demon seed was found in human food, then that meant the demon had hidden itself amongst the humans here. Yuichiro and Shinobu could both be in danger! Muichiro paused only long enough to make sure he looked human himself before racing for the door.

But as he reached for the handle, he heard a click on the other side, and the door swung open to reveal Shinobu. The Insect Hashira had an uncharacteristic look of panic on her face that made Muichiro’s blood run cold. “Is Yuichiro here?!”

“N-No, he isn’t…” Muichiro felt his heart beat faster. “Wasn’t he with you…?”

A frantic pecking at the window interrupted any response she might have had. Ginko flapped around outside, and Muichiro bolted over, almost breaking the window’s hinges as he ripped it open to let the crow in.

“Come quickly! Yuichiro is sick! He needs help!” She raced between the two Hashira, like she couldn’t decide who needed to hear the message more.

Sick? But he seemed fine earlier- Muichiro suddenly remembered the wisteria mochi and the strange seed inside. Did Yuichiro go back to that shop? He turned to Shinobu. “Shinobu, that mochi I ate, there was a seed hidden inside - a Blood Demon Art!”

“What? But how?” she asked.

“I don’t know, but the demon must have been at that shop!” Muichiro turned back to Ginko. “Where’s Yui now?”

“West, towards the city’s outskirts! Follow-”

But before she could even finish, the room was engulfed in mist that swept out the open window and into the nighttime air. Muichiro didn’t care about being seen by humans; they wouldn’t even know what they were looking at, anyway. Right now, he just needed to find his brother. He didn’t need Ginko to guide him. He knew Yuichiro’s scent. No matter where he was, he would find him. He had to.

Hang on, Yui! I’m on my way!

—

Yuichiro followed after Kyojuro for a long time. The Flame Hashira didn’t speak; he simply walked, and Yuichiro tailed behind. Several times, he thought about breaking the silence, but his words failed him every time. He struggled to keep up, the poison making it hard to stay steady on his feet or even to breathe right. His surroundings were still a dizzying blur, but Kyojuro was clear, something he could focus on, and so he couldn’t look anywhere but his deceased friend.

Finally, Kyojuro came to a stop in front of an empty alley framed by two rundown buildings. There weren’t any other people nearby. He stepped into the alley, and Yuichiro’s trepidation grew. He wasn’t stupid; he knew he’d be all too easy to kill in this enclosed, isolated location. But at this point, his body was hardly his own; the seed pulsed, spurring him to move, and the smell of smoke called him forward. All he could do was grip the hilt of his sword and follow.

Kyojuro stood inside the alley, cloaked in darkness but still smiling that damned smile. Yuichiro’s head spun and he blinked, and suddenly the Hashira was gone. A sound came from behind him, and he turned. Kyojuro was behind him now, blocking the way out. The two stared at each other, utterly silent.

“…Why?” Yuichiro asked quietly. “Why did you have to die?”

Kyojuro didn’t answer. Yuichiro knew that this was just an illusion, but for some reason his muddled mind couldn’t understand, it felt real. Like someone was really standing in front of him.

“...Well? Answer me!” he yelled, his anger rising up again and giving strength to his words. “You knew the mission was dangerous! You knew Tanjiro and the others weren’t as strong as you! So why did you choose them over us-!”

His words were cut off by a hacking cough. He’d overexerted himself, and his lungs were struggling to draw in air. But Kyojuro still said nothing. Yuichiro looked into his eyes, shining with warmth, and he couldn’t keep his anger up. Kyojuro had done so much for him and Muichiro. He owed him so much. And the longing to see him, to talk to him again, was so much stronger than his resentment.

“Why… why didn’t you take us with you?” His voice fell, meek and lost between haggard breaths. Then a horrible thought hit him, worming its way into his mind and refusing to let go. “Is it because you didn’t trust us? Did you think you’d have to protect us? Because we… because I was too weak?”

The problem couldn’t have been Muichiro; he was a demon who could kill a Lower Moon with ease, and who could stand without fear against the strongest of the Upper Moons. So the problem had to be Yuichiro, right? He was the weak one.

But his questions went unanswered still. Yuichiro fought back tears; he felt like he was drowning in the silence. “…Come on, say something! Anything!”

He never did get to hear Kyojuro’s last words. Tanjiro would have told him, but he’d been too upset to ask. He just wanted to hear that booming, confident voice again. But that would never happen.

“…You poor thing. How you must have suffered.”

Yuichiro froze. That… wasn’t Kyojuro’s voice.

An overwhelming feeling of danger swept over him, and Yuichiro drew his sword purely on instinct. His swing felt heavy and clumsy, but it struck true, and something fell to the ground. It was some kind of plant, much larger than normal, with thin spindly leaves like teeth and a bright red “mouth”. Yuichiro recognized it from a botany book: a Venus flytrap.

“Oh, you sensed that. You’re no ordinary Demon Slayer, are you?” the voice said again, sounding familiar.

Yuichiro blinked through the haze to focus on his attacker. The image of Kyojuro was still there, but the strong smoke smell was suddenly thinning, and the illusion wavered, another form showing itself underneath. A form just as familiar as the voice coming from it. Yuichiro grit his teeth and glared. “You…!”

The girl in the red kimono smirked. “Yep, me. Surprised?” She stepped forward, and her appearance shifted. Her skin turned a pale green, and her mouth split at the ends into a wide grin, long spiny teeth sprouting from her lips like that of the flytrap he’d just cut. Yuichiro didn’t respond, and she giggled softly.

“My name’s Akane, by the way. I figured I’d let you know, since we’re so well acquainted now,” she said, twisted smile growing bigger. “You’re a Hashira, aren’t you? Wonderful! If I eat you, then I’ll surely become strong enough to kill that wretched butterfly!”

“What are you… talking about?” Yuichiro struggled to keep his breathing steady. He was in really bad shape; he’d only swung his sword once!

“Well, you’ll be dead soon, so it’s nothing you need to concern yourself with,” Akane chuckled. “Ah, but you really surprised me; a human and a demon, together. Is that demon your brother, by any chance?”

Yuichiro’s eyes went wide, then his anger returned twicefold and he growled. “You stay away from him…!”

“Relax, I’m not interested in him. In fact, I’m rather annoyed that he ate the mochi I gifted you. That spell wasn’t designed to work on demons.”

“And what kind of spell is that...?” It seemed that Muichiro’s insistence on eating inedible foods had inadvertently saved his life. Well, maybe; he was still in a very bad situation. But the more the demon talked, the more Yuichiro’s head started to clear. He needed to keep her distracted until he had an opportunity to attack or escape.

“It's simple, really. Humans eat the seeds my plants create, and they fall under my spell. They evoke memories and emotions through the smells they produce, and lure my prey right to me.”

“And the wisteria?”

“My own personal touch; you could say I have a fascination with it. Though I must admit, it's a coincidence that worked out in my favor. It would have been much harder to lure you away with him around. But even then, you were oddly suspicious of a simple sample from a professional bakery. I had to get creative.”

Yuichiro glared down at his hand where the seed rested. He tried to open it again, only to feel a jolt of paralyzing pain. Even his sword in his other hand shook and it took all his willpower to hold onto it.

“Don’t bother. As long as that seed is in you, there’s not much you can do to fight back.” Akane stepped forward, and Yuichiro stepped back, intent on keeping distance between them. He glanced around; the building walls were high, but he could climb them. Or at least, he could if the damned seed wasn’t likely to lock up his whole body if he tried to run. He had to get it out, but how?

His eyes moved to his sword. The obvious solution. The painful solution. And most likely, his only solution.

“Ah, but we’re getting off topic!" Akane clapped her hands together. "You and I are very similar, you know?”

“I highly doubt that.”

“Oh, but we are! You see, I had a sibling, too. An older sister, who meant everything to me. And like your brother, she too was made to become a demon. But Onee-san was a kind person, even as a demon. She only ate criminals and corrupt men who used their wealth and power to hurt others.”

“Sounds like a real saint-!” Yuichiro bit back a scream as the seed dug in further.

“Watch your tongue, little fly, before I rip it out,” Akane snarled. "Don't you dare insult Onee-san!"

“Ugh… So where is this sister of yours…?” he asked through shuddering breaths, trying to keep the demon talking. Anything to distract her and keep her from realizing what he was about to do. “Does she know what you’re doing…? Surely a demon who only kills bad people… wouldn’t approve of you eating a kid?”

“Hm, you’re probably right. She wouldn’t.” Akane’s voice was soft but thick with bitterness. “But it’s not like I can ask her. She died long ago, killed by that wretched butterfly.”

“So you’re after revenge? What will you do… if you get it? Will you just… keep killing innocent humans, even if your sister wouldn’t have wanted that?”

“I’m not sure,” Akane shrugged. “I’ll think about that when I get there.”

Yuichiro resisted the urge to make another sarcastic retort, if only to spare himself more pain. This one was yet another demon that couldn’t be reasoned with. He couldn’t blame Muichiro for feeling insecure when all but a handful of his kind really were unrepentant monsters. But then again, Yuichiro didn’t really care if the demon had any remorse or not. All he needed was for her to let her guard down.

Akane sighed. “Well, I was having fun talking to you, but now your questions are starting to piss me off. So I think it’s time I ended this. Be a good little fly and fall into a happy memory while I kill you, okay?”

The smoke smell returned, and Yuichiro’s head throbbed. Akane’s figure blurred and was once again replaced with the image of Kyojuro. The Flame Hashira, the man who was like an older brother to him, smiled bright and nostalgic. The sense of longing he felt was undeniable; Yuichiro missed him. He missed him so much.

And like hell he was going to let this monster keep using his memory against him.

“Fuck you, you don’t control me.”

With all his will, Yuichiro forced his fingers open to expose the seed. Then he shifted his grip on his sword and stabbed it through his left hand. He screamed; the pain was almost too much to bear. But a tiny, shrill shriek rang out as his blade ran through the back and out his palm, tearing out the seed and its thorny roots. Impaled on the blade, it wriggled and writhed before going still.

The smoke smell grew faint. Through the pain, Yuichiro felt his head clear and control return to his body. Control he needed to leap back as Akane’s claws lashed out. He jumped back and tried to pull out his sword, only to gasp and fall to one knee. If the pain of stabbing his own hand was excruciating, trying to pull it out was infinitely worse. Even though the tip of the sword protruded only a few inches through his palm, trying to slide it back through his muscles and nerves was agonizing.

“Well, well, you’re not as weak as I thought you were.” Akane snarled, stalking closer. “But what does it matter? You’ve wrecked the hand you need to wield that sword effectively, and for what? So you can die fully aware? Fine then; I’ll make it slow and painful!”

She raised her claws to strike. Yuichiro grit his teeth and-

“Mist Breathing, First Form: Low Clouds, Hanging Mist…”

That voice…!

A red mist sword stabbed through Akane’s chest.

“…Devour!”

The sword convulsed, as if alive, and burst into a cloud that began to engulf the demon. Her eyes went wide in panic. “No!”

Something moved under her kimono, and Muichiro transformed a split second before the fabric was ripped to shreds by dozens of flytraps bursting from her back, jaws snapping at his gaseous form. The blood mist faded away as he blew past her and reformed in front of Yuichiro, fangs bared and a white mist sword in his hands.

Yuichiro smiled, relief flooding him. “Muichiro...!”

Akane looked shocked to see him. She raised a hand to her chest, melted to expose her ribs and beating heart, but as it regenerated, her surprise turned to fury. “You little brat! Stop getting in my way!”

Muichiro didn’t say anything. He only snarled, snake-like pupils glaring furiously and cracks forming along his face. He clenched his fists and the mist sword turned red as he lunged at the demon.

Akane’s eyes narrowed. She pulled something from her sleeve and tossed it at the younger demon. Muichiro’s body moved on instinct, slashing through the object, only for it to burst into a cloud of purple dust right in his face. He gasped, inhaling the dust, and immediately broke into a fit of violent coughing. His hands flew to his throat as his breathing became rough and strangled. He stumbled back and fell to his knees, hacking up blood with each desperate breath.

“Muichiro!” Yuichiro shouted. Protective fury rushed through him, and with a cry he finally pulled his sword free. White-hot agony flooded in, but Yuichiro pushed through to run forward and put himself between his brother and the demon. He clenched the hilt of his sword with both hands, trying to ignore the burning in his injured hand.

Akane’s mouth turned in a cruel smirk. “Aw, poor thing. Wisteria poison’s no fun, is it? I would know.”

“You…!” Yuichiro felt himself shaking with anger.

“Now, now! Better worry about yourself, first! My plants can do more than just lure in prey, after all!” Akane grinned, and her flytraps pointed towards them, opening their mouths. Yuichiro braced himself for an attack.

“Blood Demon Art: Entrapping Scent of Terror!”

Sickly green gas poured from the mouths of the plants and washed over the two Hashira. Yuichiro barely managed to hold his breath in time as his vision became obscured. He gathered the air he had left and readied his sword.

Mist Breathing, Third Form: Scattering Mist Splash!

His swing blew the gas back, though his poor position and injured hand failed to clear it entirely. Almost immediately, a series of coughs ravaged his lungs, still weakened from the poison. But he pushed through the pain as he turned back to check on his twin. “Mui, are you-!”

A flash of claws inches from his face cut him off. Muichiro scrambled back, staring through his big brother with a distant gaze filled with terror. “St-Stay away! You can’t be here! I got rid of you!”

“Mui? Mui, it’s me!” But his words were useless. Muichiro didn’t acknowledge him at all; his breathing was fast, too fast, and punctuated by hacking coughs from the wisteria powder. He crawled further away before curling in on himself, shaking his head and covering his ears, claws drawing blood from where they dug in too hard.

“Don’t bother; he can’t hear you, not in a memory that powerful.” Akane chuckled. Yuichiro felt his rage toward the demon grow stronger; how dare she torment his brother! But before he could act on his anger, Akane’s flytraps opened their mouths again. The demon grinned maliciously. “Your turn now; be sure to scream for me!”

The green gas poured forth again. Yuichiro tried to hold his breath again, but his lungs chose that moment to seize up and send him into a fit of coughs that let the gas into his body. It clouded his senses and he felt dizzy as a new smell hit him. The smell of a forest on a hot summer night, and the smell of blood-

Yuichiro froze. He wasn’t in the alley anymore. He was… he was at home, their old home. It was dark but for the light of the moon. And gazing down at him was a tall, terrifyingly majestic demon, six eyes glowing in the darkness. Upper Moon One.

A sudden terror seized him, stronger than any he had felt since seeing this demon for the first time. He was paralyzed, unable to even lift his sword as Kokushibo slowly drew his blade. Yuichiro’s conscious mind screamed at him that this was wrong, that he’d never even seen the Upper Moon that summer night. But his body was still frozen in fear. Kokushibo lifted his sword-

“Insect Breathing, Dance of the Dragonfly: Compound Eye Hexagon!”

A sudden gust of wind scattered the gas surrounding the twins, cracking the illusion. The paralyzing terror abated, and Yuichiro was able to move again. The illusion started to fall apart, revealing Shinobu standing before him. Her hat had fallen off to reveal her butterfly hairpin beneath. She knelt down, her eyes going wide at the sight of his bloodied palm, but she recovered quickly and pulled something from her handbag.

Yuichiro almost backed away, the remnants of the gas evoking an unnatural fear, but he managed to resist the compulsion. A second later, he felt a sharp prick in his other arm. Shinobu pulled away and revealed an empty syringe.

“There. It won’t do anything for your injury, but it’ll help to purge the poison from your body. It’s wisteria-based, though, so I can’t give it to Muichiro. I’m sorry.”

Slowly, Yuichiro felt his body become lighter, his breathing easier to control. The last of the illusion faded away, and he was able to see and think clearly. Shinobu stood up and turned to face Akane. The demon stared at the Insect Hashira with barely contained fury, shreds of her flytraps laying all around her.

“You…!”

A somber look crossed Shinobu’s face. “So, it is you.”

Akane snarled, more flytraps sprouting from her back. “I've been waiting for this; I’ll make you suffer for what you did!”

“Will you now?” Shinobu spun her sword in her hand. Then she leapt forward, faster than the eye can blink, and stabbed through Akane’s chest. The flytraps shrieked and lashed out, but Shinobu leapt back just as quickly, returning to Yuichiro’s side. “You should know that flytraps are meant to lure in and surprise unsuspecting prey; they’re not very good at catching quick-moving insects.”

The demon gasped and slumped forward, but then she lifted her head, a wicked grin on her face. “Ha, you think your little tricks will work? I’ve altered my body to be immune to wisteria poison. Without the strength to cut my head, there’s nothing you can do to kill me!”

Shinobu was silent for a moment. Then she smirked, a soft chuckle escaping her. “Oh, you poor girl, is that what you think?”

“Huh?” A second later, the demon’s body tensed up. The flytraps withered, and a diseased purple bloomed from her stab wound. “W-what…! How…?”

“Did you think I’ve been using the same poison all this time? I’ve developed many different wisteria-based poisons. It’s simply a matter of finding one that works on you.”

“You… You smug little…! It doesn’t matter! If it’s wisteria poison, I’ll break it down! I won’t let you kill me! Not before I’ve had my revenge!” The purple color stopped spreading, and more flytraps sprouted from all over her body, ready to continue the fight.

But then the air shifted. It felt familiar, and Yuichiro spun to face his twin. Muichiro had gone deathly still, and a white mist billowed up around him. It cradled him and brushed against the blood running down his face. And then the remnants of the fear gas were blown away by a rush of burning red. The Devouring Mist rose high into the air, roaring with fury.

Panic filled Yuichiro, his mind flashing back to the incident on Mount Takao. Just as it had back then, the blood mist was responding to Muichiro’s fear and going out of control. Shinobu backed away cautiously, and even Akane shrunk back in trepidation. And as much as he wanted to take a sick pleasure in her cowering before Muichiro’s power, that same power in a populated area would soon spell disaster if left unchecked.

“Yuichiro! Listen to me!” Shinobu commanded, drawing his focus. “I’ll stall the demon; you calm Muichiro down, now!”

Before he could even respond, she shot forward to engage Akane. The flytraps lunged for her, but she expertly danced around each one and delivered another quick stab at the demon. For a second, Yuichiro was in awe of her speed and skill, but then he remembered himself, and looked back to Muichiro. He could barely see him through the swirling mist.

Calm him down? How? But there wasn’t any time to think; the blood mist was getting bigger. Mist beasts roared and lashed out, scoring gashes through the brick walls around them. Yuichiro had no idea if these buildings were inhabited or not; if they were, then this bad situation was suddenly even worse.

“Damn it… Hold on, Mui…!” With no time to plan, Yuichiro resorted to doing the same thing he’d done on Mount Takao: push through the mist and hope for the best.

Except once again he seemed to forget that burning mist and a grievous stab wound did not mix. The pain in his palm flared, and Yuichiro screamed. But at the center of the raging storm, Muichiro jumped, his head shooting up to look directly at his brother. For a moment, his eyes regained clarity. “Yui?! No… no, stay away! I’ll hurt you! I’ll-”

But Yuichiro didn’t let him finish as he drew his little brother into a tight hug. This was agonizingly familiar, like he was reliving the horrible memory just as Muichiro was. Except this time, holding him like this, he now knew what to do.

“It’s okay, I’m here for you. I’m not going anywhere,” he said softly, running his fingers down his twin’s back to soothe him. “I know you’re scared, but this is all in the past. We already lived through and overcame this. So just breathe.”

“I… I can’t…!”

“You can. You’re strong, Muichiro. You have infinite strength, remember? You can beat this. Don’t let that damned demon control you!”

Muichiro let out a quiet gasp. For a moment, there was nothing but the roaring of the mist. But this time, Yuichiro's words reached him. Muichiro raised his arms and hugged him back, his head resting against his shoulder.

The blood mist slowed and thinned, its furious howls dying down. Then Muichiro gently pushed his twin away, and the mist converged on him, forming some sort of shell. His panicked breaths evened out into the full, rhythmic motions of Total Concentration Breathing.

Yuichiro sighed in relief. A relief that soon shattered when he heard Shinobu cry out. His head snapped towards the fight in time to see her stumble back, a flytrap biting into her wrist holding her sword. Akane snarled, a sound full of hatred. “I’ve had enough of this! It’s time you suffered like I did!”

“Shinobu!” Moving on instinct, Yuichiro grabbed his sword and shot forward. He leapt in front of the Insect Hashira and slashed through the flytrap holding her just as the other plants opened their mouths.

“Blood Demon Art: Entrapping Scent of Tragedy!”

A dark blue gas poured forth, engulfing the whole alley. There was no time to dodge or hold his breath; Yuichiro braced himself for what he would see as the gas filled his lungs. The world turned and tilted, and a new smell filled the air. The smell of heavy rain, bringing to mind a fierce storm-

No.

Yuichiro saw the inside of his home. The small house shuddered against the pouring rain and howling wind outside. Lightning flashed and thunder boomed beyond the walls.

“Yuichiro.”

No. Please, no.

He looked towards the entrance, and there was his father, wearing a thick straw mantle and wide-brimmed hat. He had a hand on the door, ready to slide it open to face the storm outside.

“Don’t worry about me. Take care of your brother.”

Not this. Anything but this...!

In the corner of his eye, something moved. Urgency clawed at the edges of his reeling mind. Snap out of it! This is just an illusion! It isn’t real!

But his heart wouldn’t listen. Despair flooded in, drowning out all rationality. In that moment, he forgot himself, lost in the memory. He was a child again, watching his father get ready to leave and never come back. He was a child who was about to lose both his parents in a single night.

“I’ll be back when I’ve found the herbs.”

“No, don’t go! Mother’s a lost cause! Muichiro and I need you here!”

But his father turned away, his words unheard. No… no…! He was going to leave! He was going to die! Nothing was going to change!

His hands clenched around something, and pain lanced up his left arm. But the pain grounded him, and the vision before his eyes flickered. The image of his father blurred, a figure in a red kimono taking his place before the vision reasserted itself. Yuichiro gasped and looked down, a white blade appearing in his mind’s eye.

His father opened the door, letting in the storm outside, and something in Yuichiro snapped and saw red.

His sword stabbed through his father’s chest. The two of them crashed through the half open door and into the pouring rain, slamming against a tree. The illusion fell apart, his home replaced with the run-down alley, the tree with a brick wall. And instead of his father, Akane’s furious face stared back at him. Shock chilled him as reality flooded back in.

“You-”

Yuichiro’s fist slamming into her cheek cut her off. Her spiny teeth sliced the flesh of his knuckles, but the pain didn’t even register. Even the screaming in his hand upon impact was ignored. The shock turned into a fire that seared him from the inside out. He pushed his sword further into her chest and twisted it.

“How dare you… How dare you wear his face…!”

He wretched the sword out violently, metal sliding against bone. The flytraps raised their heads, but Yuichiro was faster. He swung, and his blade slashed through the demon’s neck and slammed against the brick wall behind her.

A snap rang out as Akane’s head and the end of his sword both hit the ground. Yuichiro was left holding half of a blade, breathing heavily, adrenaline surging through his body. He heard something behind him, and he spun around with his broken sword raised to strike.

“No need to worry, it’s just me,” Shinobu’s sweet voice broke through the haze of red. Her hands were raised in surrender, though she still held her sword. She came to stand beside him, looking down at the head of Akane, who stared up in wide-eyed disbelief.

“I… lost?” she breathed. “No… No, I can’t have lost! I can’t die here! Not until I’ve avenged Onee-san!”

“Akane…” Shinobu sighed, a somber look in her eyes. “You don’t even remember what really happened that night, do you?”

“What are you-”

“I did come to kill your sister that night, yes. As a Hashira, it was my duty. But she surrendered without a fight. She wanted to die. She didn’t want to hurt anyone else, and she didn’t want you to have to live with what she’d done.”

Yuichiro looked at her, shocked, then back at the demon. Akane’s face was one of horror, of one that learned a truth too awful to be real. “No… no, you’re lying! Onee-san would never do that! She’d never leave me alone!”

“It’s the truth. Your sister loved you, and she wanted you to live a good life. She never-”

“Shut up! Don’t tell me what she would have wanted! You don’t know anything! Onee-san… Onee-san!”

Even though she was already crumbling, a sound came from her headless body. It stumbled away, skin rippling and convulsing. Yuichiro and Shinobu prepared themselves as dozens upon dozens of flytraps erupted out-

A roar filled the air, and the massive maw of a red mist beast chomped down on the demon’s body. More joined in, slamming down in a frenzy that swallowed Akane's head along with it. Shinobu gasped as she and Yuichiro backed away to avoid touching the mist.

The beasts roared and faded away, revealing Muichiro behind the sanguine fog. His chest heaved with rage, but as the mist returned to him, his breathing evened out. Silence fell. The demon took a few steps forward, then launched himself into Yuichiro’s arms. He clung to him and buried his face in his chest.

“I’m glad you’re okay…” Muichiro mumbled against his yukata.

“…Yeah, me too.” Yuichiro tried to smile, but his attempts felt hollow. The anger and adrenaline drained from his body, leaving him empty. Only the pain in his hand, worsening with each second he was aware of it, reminded him that he was still alive.

“Yuichiro, let me see your hand,” Shinobu instructed. Yuichiro sheathed his broken sword and raised his hand for her to look. It was also the first time he was looking at it properly, and it was not pretty. The stab through the back was bad enough, but on the other side, a large chunk of his palm had been torn out when he ripped out the demon seed. Even with Recovery Breathing, it was still bleeding.

Muichiro gasped, eyes wide with horror. Shinobu also looked worried. She took a roll of bandages from her bag and started to wrap it up tight.

“…Shinobu, that demon…” Yuichiro started as she worked.

Shinobu grimaced, then sighed. “It’s my fault. I didn’t know she was there, and seeing her crying over her sister reminded me so much of Kanae and myself. Even though it was her sister’s last wish, I couldn’t bring myself to comfort her. I let her run away and become like this. All the blood she spilt, all the humans who died, are on my hands.”

Yuichiro frowned. “No, it’s not. She was human back then, right? You aren’t to blame for what other people choose to do.” Akane had brought this on herself. She chose to be a monster and tarnish her sister’s memory in the name of a revenge she wouldn’t have wanted. He had no sympathy for her.

“...Hmph, you should listen to your own advice, Yuichiro.” Shinobu smirked.

Yuichiro blinked, confused. Then he realized the hypocrisy of his words. But this was different… right? He had been with Kyojuro; he could have done more to convince him. But maybe he couldn't have. Maybe he was always too weak to change anything.

“To think things would turn out like this…” Shinobu went on, more to herself than anyone else. “I hoped to bring her some comfort, but… well, I guess there’s no point in dwelling on it now.”

He knew what she was saying. The demon was dead; there was no point wondering what could have been. If only Yuichiro could take that lesson to heart. “…Shinobu? You think that… I shouldn’t blame myself or Kyojuro, but the demon that killed him, right?”

Shinobu blinked and looked at him, as if searching for something, then steeled her expression and nodded. “I do.”

Yuichiro could only nod back. Could he really just accept that, though? Couldn't he have done something different? He wasn't sure anymore.

Shinobu finished dressing his hand, but it wasn’t long before red started bleeding through. “You need treatment. There’s a hospital close by; we’ll go there.”

She turned to go, but Yuichiro stopped her. “Wait!” She looked back, and he continued. “I… I’m sorry about what I said earlier. About Kanae, and about you being weak. I shouldn’t have said that.”

Shinobu blinked, then sighed and turned to face him fully. “Yuichiro… I can’t say that I wasn’t upset, but I'm quite familiar with people who lash out when they’re in pain. And… I crossed a line as well, by pressuring you to talk about Rengoku when you weren’t ready. I should have known better.”

Yuichiro shook his head. “No, you didn’t do anything wrong. If you didn’t say anything, then I would have just kept going without ever talking about how I really felt.”

“Nii-san?” Muichiro looked confused, lacking context, but that didn’t stop him from being concerned for his twin.

Yuichiro continued speaking. “Shinobu, you’re not the weak one… I am. I always have been.”

“What are you talking about, Nii-san?” Muichiro’s concern only grew. “You’re not weak.”

“I am, though. If it weren’t for you two, I probably would have died to that demon. I fell right into her trap and let her manipulate me.” All because he couldn’t face his feelings about Kyojuro’s death. The sorrow and the fear that he wasn’t strong enough to change anything. “I’m not a strong person at heart. I can’t lose the people I care about and keep moving forward. It hurts too much.”

And when Yuichiro felt hurt, he got angry. Because when he was mad, at his mother, at his father, at Kyojuro for dying, he could hide behind that anger and ignore his other emotions. It was easier to be bitter and resentful than it was to admit that he missed them. The grief and the guilt saying that he hadn’t been good enough, that he could have done better, were too painful to bear. Anger was the armor protecting his weak, fragile heart.

Yuichiro hadn’t even realized he’d started crying until he felt tears running down his cheeks. He closed his eyes and tried to wipe them away in a futile effort to keep more from falling. Muichiro leaned his head against his shoulder.

“Nii-san, this isn’t just about Kyojuro, is it?”

Yuichiro felt like he’d been struck. Though it wasn't Muichiro's intention, his words brought the full weight of what he’d done crashing down on top of him. He’d run a sword through his own father. Maybe his mind knew it was an illusion created by a demon, but he couldn’t deny that his heart had driven his hands too, cut open and bleeding with anger and resentment.

But even as he grasped the horrible weight of his sin, Yuichiro couldn’t bring himself to feel guilty. His mind and heart were at war with each other.

He stabbed their father who raised them and loved them.

He stabbed their father who died and left them with nothing.

Yuichiro felt faint, both from the blood loss and his own growing distress. Muichiro and Shinobu were both looking at him, as if waiting for an answer. But he couldn’t… he couldn’t say anything. Not here. Not now. Maybe not ever.

He shook his head and huffed. Anger returned to shield his heart. “…Come on, let’s go. I feel awful.”

Neither of his companions looked happy with leaving things as they were, but Shinobu relented to his silent plea to not push any further. “Follow me.”

Yuichiro nodded and followed behind. But Muichiro ran forward and wrapped their arms together, holding him close, as if desperate to give him any comfort he could. “You’re not weak,” he repeated, holding back tears. “You saved me tonight, remember? You’re strong too, Yui.”

Yuichiro didn’t, couldn’t respond to that. Because Muichiro was wrong. He wasn’t strong. He just had no choice but to put what strength he did have into protecting the only family he had left. Because he would truly break if he lost Muichiro, too.

They continued on, and Yuichiro looked up at the sky, at the stars. He imagined his parents and Kyojuro looking down at him, and felt ashamed.

Chapter Text

“Muichiro, are you still awake?”

Shinobu’s soft voice and the quiet closing of the door behind her broke the stillness pervading the hospital room. Muichiro looked away from where he’d been watching the rhythmic rise and fall of his sleeping brother’s chest to face the Insect Hashira.

“Yeah, I’m awake.” There was no way he could sleep right now. He tried to smile. “Those pills really did their job. I haven’t seen him this peaceful-looking in a while.”

The injury to Yuichiro’s hand had been severe enough that a skin grafting surgery was needed to repair it. Though he’d protested staying at the hospital, Shinobu had insisted he stay at least one night to make sure there were no complications after. But the pills prescribed for his pain had a sedating effect on the young Hashira, and he was now in a deep sleep.

Shinobu took a seat in the chair beside Muichiro and set his basket on the floor. “We’ll leave tomorrow. I can take care of the rest of his treatment at the Butterfly Estate.”

Muichiro nodded. “Thank you.”

“How are you feeling?” she asked. With all the stress of getting Yuichiro the care he needed as quickly as possible, this was the first quiet moment they’d had all night.

“I’m fine, really,” Muichiro looked back at his brother. “The Devouring Mist protected me from that demon’s last attack, so I wasn’t affected by whatever it was.”

“What were you doing? It looked like you were wrapping the mist around yourself.”

“Oh, um, I was using it to get rid of the demon’s blood art. By breathing in the mist, I was able to get rid of its effects.”

“I see. That sounds quite useful.”

Muichiro nodded in agreement. “What about you?”

“I was able to hold my breath in time, so I wasn’t affected either,” Shinobu explained. “But I was only able to do that because Yuichiro put himself between me and Akane. You could say he saved me at his own expense.”

“That sounds like Nii-san, alright,” Muichiro sighed. “He’s always putting himself in danger for my sake, even when it’s not necessary. I wish he would take more care of himself before worrying so much about me.”

“Hmph, you’d have more success asking the sun to not rise,” Shinobu smirked.

Muichiro glanced her way, unsure of how to broach the topic on his mind. “…Shinobu, what were you two talking about? About him calling you weak?”

Shinobu’s smile fell. “That’s not for me to answer. It’s in the past, anyway. I’m not angry anymore.”

“But why would Nii-san say that he was weak?” Distress crept into Muichiro’s voice. He remembered Yuichiro saying he felt that way long ago, back when it was just the two of them living in their childhood home. He’d thought they’d moved past that, but it seemed that wasn’t the case. But Yuichiro never liked talking about his own feelings, and maybe Muichiro had been too passive in supporting his brother. He should have done more to help.

Shinobu closed her eyes. “Perhaps what happened tonight has reopened some old wounds. I’m… truly sorry for how this mission turned out. It was my idea to bring you two along, after all. I can’t help but feel responsible for both of you.”

“Don’t blame yourself, Shinobu. We’re Hashira, too,” Muichiro shook his head. “And besides, I think Nii-san will be happy that he was able to protect you. We weren’t able to help Kyojuro, so we’re both happy that we could help you.”

Surely Yuichiro had seen the same parallels. If the demon was truly immune to all wisteria poisons, Shinobu would not have been able to win. But she couldn’t run away and abandon the humans under her protection, either. His big brother considered Shinobu a friend, too; if she had died in such circumstances, it would have hurt him even more.

“Perhaps you’re right,” Shinobu said, a small but genuine smile coming to her face. Then it slipped, and she gave him a serious look. “Muichiro, will you tell me what you saw tonight?”

Muichiro’s eyes went wide. He looked past Shinobu; in the corner of the darkened room, he almost thought he could see a shadow, six turquoise eyes watching him. Its words echoed in his head.

Why do you still pretend to be something you’re not?

Do you know how strong you could be, if only you would cast aside this useless obsession with humanity?

You are a demon. Accept your nature.

Muichiro blinked and the shadow disappeared. He looked away.

“…It’s… not something I want to talk about.”

Shinobu nodded, understanding. “You and your brother are alike in many ways.”

Muichiro knew what she meant by that, but he didn’t say anything. He decided to change the subject by pulling out his brother’s sword hidden in his haori, which Muichiro himself was wearing for now. He unsheathed the half blade and frowned.

“Nii-san’s sword broke in the fight.” He had never seen Yuichiro strike so fiercely and so recklessly before. He wondered what the demon had forced him to see; it must have been awful.

“Yes, I’m afraid he’ll have to wait for a new one to be delivered,” Shinobu said. “Ah, but Yuichiro’s swordsmith passed away recently, didn’t he?”

“Yeah. Mr. Tetsuido died of heart disease two weeks ago.” Muichiro felt a pang of sadness at the thought of the man. He was always kind to him and his brother whenever he came to visit.

“Perhaps you should go to the Swordsmith Village yourselves, then.”

“Huh? Go to the Swordsmith Village?”

Shinobu nodded. “Indeed. It would be a good idea for Yuichiro to meet with his new swordsmith personally. Not to mention, the village is home to a hot springs that is said to have wonderful healing properties.”

“You think it would help Nii-san’s hand?” Muichiro asked hopefully.

“I would advise against exposing his wound to hot water until it’s fully healed,” Shinobu gently reined in his excitement. “But it’s still good for all sorts of aches and pains. I highly recommend it.”

Muichiro nodded, already anticipating the trip with glee. It would be like a vacation; they were both long overdue for one, and Yuichiro especially could use the break after such an awful mission. And it would give them some time on their own for Muichiro to talk to his brother about what was plaguing him. Simply waiting for Yuichiro to speak up wasn’t enough; he would have to be more assertive himself.

It was a golden opportunity; Muichiro wouldn’t let it go to waste.

—

“Go to the Swordsmith Village?”

The next morning, Yuichiro listened as his twin relayed Shinobu’s suggestion. It was a sensible idea; he needed a new sword, and with his left hand in its current condition, the amount of training he could do would be limited. There was really no reason not to go, as he’d be stuck resting at home or the Butterfly Estate anyway. And after last night’s battle, it might do him well to go somewhere new, someplace not so entrenched in memories he didn’t want to think about.

It would be a good, if temporary, distraction from all his worries.

And so it was that, a week later, the twins found themselves being transported to the enigmatic Swordsmith Village. Transported was really the only word Yuichiro could use to describe it, because what else could describe being blindfolded and carried on the back of a Kakushi - several Kakushi - the entire way? Muichiro had it even worse; despite being in his basket and unable to see anything, he still had to wear a blindfold and nose plugs so he wouldn’t smell anything that could expose the village’s location. It was an insane amount of precaution, but both twins understood the need for secrecy, so they obliged with minimal complaining.

Upon arriving at the village, Yuichiro was taken to meet with the chief first. The tiny chief told him his new swordsmith was a man named Kanamori, who was currently out of the village but would be back within the week. Thus, the twins were left with an abundance of free time to do whatever they wanted.

Yuichiro spent the first day exploring the village, which was small and quaint to help preserve its secrecy. Despite the peacefulness of the village, he couldn’t help but feel frustrated. He had all this free time, but couldn’t train or do anything productive. He felt useless, just waiting for his sword to be repaired and his left hand to heal enough to grip a hilt without shooting pain running up his arm.

But eventually night fell, and Muichiro was able to come out of his basket. They re-explored the village, Yuichiro giving his twin a tour of where everything notable was, such as the chief’s house and where they were staying. And of course, Muichiro was eager to find the hot springs and take a relaxing soak. So after asking for directions, the twins went on their way.

As they reached a set of steps going up a hill, Muichiro gasped in excitement. “I smell the hot springs!”

Yuichiro sniffed the air, picking up a faint sulfur smell that grew stronger as they traveled upwards. He felt a discomfort building in the pit of his stomach; ever since their last mission, strong smells tended to make him feel dizzy and nauseous. But he pushed through it and followed behind Muichiro until the village’s famous hot springs finally came into view.

Muichiro jumped right into the steaming water, not even bothering with taking off his clothes first. Not that he needed to, as they were made from his own cells anyway. Yuichiro took his time getting in, tying his hair up and keeping to the edges of the spring, careful to keep his left arm resting on dry land.

Up to his chest in the hot spring, Yuichiro finally allowed himself to relax. The steaming water soothed his tired muscles and even the strong sulfur smell wasn’t quite so bothersome anymore. Muichiro swam up to him, lightly splashing the water and laughing.

“Isn’t this great, Nii-san? We haven’t been to a hot spring in so long!”

Yuichiro nodded. It had been a while, and he had to admit it felt nice to relax like this. He lowered himself in as much as he could while keeping his hand dry, and just basked in the moment.

Then a sound startled him from his reverie. He looked up, and noticed that they weren’t alone. At the far end of the hot spring was a tall teen with dark hair shaved at the sides. He had his back turned to them, seeming preoccupied with something, and it was unclear if he even knew they were there.

“Oh, hi there!” Muichiro called cheerfully, swimming over to greet the teen before Yuichiro could stop him.

The older boy froze, pointedly keeping his back turned to Muichiro. As the young demon swam up to his side, he turned away, again keeping him from seeing his face. Yuichiro watched this with confusion and suspicion; what was he so focused on hiding? He seemed familiar, but he couldn’t quite place where he’d seen him before.

“My name’s Muichiro, and over there is my brother, Yuichiro!” Muichiro introduced them, trying to look around the boy and see his face. “What’s your name?”

“…Genya,” the teen said curtly, still not facing him. “Now go away.”

“Genya… Genya…” Muichiro ignored the order, looking thoughtful with a hand on his chin, before suddenly lighting up in recognition. “Oh, I know you! I’ve seen you at the Butterfly Estate!”

As soon as his brother said that, realization struck Yuichiro as well. That’s right, he had seen Genya at the Butterfly Estate before. Aoi complained about him sometimes, saying he was too abrasive but that he also acted weirdly timid around girls.

Wait… was that why he wasn’t looking at Muichiro? Because he thought he was a girl?

Muichiro tilted his head and tried swimming around the other side of Genya, but he turned away from him again. “I told you to go away! I came here to be alone, so stop bothering me!”

“But why?” Muichiro asked, confused. “We’re all guys, so there’s nothing to worry about!”

“Plus, this is a public spring. We have just as much right to be here as you do,” Yuichiro added. This guy’s attitude was starting to annoy him.

Genya growled and finally turned to face them. And then his eyes went wide and his anger turned to fear. “Oh fuck, you’re the two Mist Hashira…!”

Yuichiro gave an irritated glare; this guy had a mouth on him. But Muichiro didn’t seem to mind, smiling brightly and showing off his fangs. “Yeah, we are!”

“Shit…” Genya nervously cursed again. “Look, I’m sorry for being rude, okay? Please don’t tell my brother about this!”

“Huh? Who’s-” and then Yuichiro remembered: Genya’s surname was Shinazugawa. He’d thought it might have been a coincidence that he shared a name with the Wind Hashira, but now it was clear that wasn’t the case. “Wait, is Shinazugawa your brother?”

“…Yeah, he is…” Genya looked like he had let a little too much slip and was regretting it. “I… guess he never told you about me, huh?”

Yuichiro shook his head. Genya looked surprisingly pitiful, a disappointed expression on his face. And then Muichiro spoke up, oblivious to the somber atmosphere.

“Genya, why do you have fangs?”

Genya froze, his sadness vanishing as he quickly looked away. “I don’t. You must be seeing things.”

“No, I definitely saw them,” Muichiro insisted, half-turning to mist and floating around to peer directly at Genya’s face. “Open your mouth.”

“Wha- Don’t try to look in people’s mouths, you weirdo!” Genya snapped and pushed him away.

“Hey, don’t call Muichiro a weirdo!” Yuichiro yelled, ready to jump right to his twin’s defense.

“Shut up! If he’s being weird then I’ll call him a weirdo!” Genya shouted back, now hiding his mouth with one hand while he used the other to shove Muichiro away again. “And you, get away from me! Don’t you have anything better to do than bother strangers?!”

“No, not really,” Muichiro answered honestly. Nevertheless, he complied and settled back in the water. “Normally we’d spar, but Nii-san can’t do that right now. We’re here on leave, but we’re not really sure what there is to do. Do you have any ideas, Genya?”

“Why are you asking me that?” the older boy grumbled.

“I don’t know, you just seem like you’ve been here longer than us so you would know more,” Muichiro shrugged. “Plus, if it’s something we can all do together then-”

“Hey, don’t include me like we’re friends!” Genya interrupted, face red and fuming at the ears. “If you really want something to do, then how about you go spar with the training doll here?”

“Training doll?” Yuichiro sat up to listen better.

“Yeah, it’s some sort of life-sized doll that can move and fight like a human swordsman. It’s really old, apparently, but it still works, and you can use it as a training partner to improve your swordsmanship.”

“That’s so cool!” Muichiro beamed, eyes sparkling. “Nii-san, let’s go look for this doll tomorrow!”

“Shinobu said I need to wait a few more days before I can wield a sword again,” Yuichiro reminded him. But he had to admit he was interested in seeing this training doll for himself.

“Okay, we’ll go look for it then!”

“Great, you do that. I’m gonna head out now,” Genya grumbled, moving to leave the springs. “You two have fun doing whatever.”

“Oh, okay! Bye, Genya! We’ll see you later!” Muichiro waved the boy off as he hurriedly grabbed his clothes and left, his face still red. Yuichiro watched him go, then let out a huff.

“What’s his problem?”

Muichiro shrugged, empty eyes still looking in the direction Genya had gone. “I don’t know, but… he had a strange smell.”

Yuichiro tilted his head. “What did he smell like?”

“I’m not sure. Like a human but… not.”

Well that was unhelpful. “Speaking of strange, did he really have fangs?”

Muichiro shrugged again. “I thought he did, but I’m not sure now.”

Yuichiro frowned, stumped. What could it mean? Demons had fangs, but Genya couldn’t have become a demon. Yuichiro had seen him in the sun before, and news like that would surely have reached the Corps by now. But he didn’t sense anything dangerous, beyond the rudeness that seemed to be a Shinazugawa family trait. “Well, whatever. We don’t need to be worrying about jerks like that, anyway.”

Muichiro hummed, his face still blank. Yuichiro had no idea what he was thinking. “…Mui? Are you okay?”

“Huh?” His twin blinked, then smiled. “Yeah, I’m fine! Sorry, I was just thinking!”

“About Genya?”

“Yeah, but it’s nothing to worry about,” Muichiro leaned back in the hot water and idly splashed around. “Anyway, you’re right; we should relax and enjoy ourselves while we’re here! After that last mission, we’ve really earned it!”

“Hmph, got that right…” Yuichiro’s mood soured again thinking of that mission. Muichiro noticed and frowned. He swam closer to Yuichiro and looked into his eyes.

“Nii-san, I know our last mission didn’t go… well,” he glanced away, then looked back and smiled. “But we won. It’s over, so you should just focus on recovering. And if you want to talk about what happened, then I’m here for you. Whatever it is, I’ll listen.”

Yuichiro felt his heart rate pick up under his twin’s gaze. He appreciated Muichiro’s concern, he really did, but he just wasn’t ready to talk about what really happened during that battle. The sulfur smell of the hot spring was suddenly bothering him again, and he stood up.

“Let’s head back. We’ll miss dinner if we stay here too much longer.”

He tried to ignore the way his heart ached upon seeing his brother’s smile fall, a dejected frown taking its place. But Muichiro didn’t say anything; he only nodded and followed behind, the words unsaid left hanging between them.

—

Three days later, Yuichiro went searching for the mysterious training doll. His hand was healing well thanks to his Recovery Breathing, even if it still ached from time to time, and he could start training with a sword again. As long as he didn’t overdo it, anyway.

The day after their arrival, their fellow Hashira Mitsuri also showed up at the village. She was there to make adjustments to her own sword, though of course she was just as happy to spend time with the twins as Muichiro was. Yuichiro wasn’t quite as excited, but at least her endless, overwhelming energy served as a way to make time move faster.

They hadn’t seen Genya since the first night. Last they heard, he was in his room and refused to come out. Someone else had also shown up yesterday, but Yuichiro hadn’t cared to find out who, retiring early to rest and eat dinner with Muichiro in their room.

Over the past few days, Yuichiro had asked around the village about the doll, and apparently it belonged to one of the families here whose head of house had passed away, leaving custody of the doll to his young son. But the boy, Kotetsu, hadn’t been seen recently. He’d last been spotted entering this part of the forest early this morning, so it was the best place to search.

“Do you smell anything, Mui?” he asked.

“Not really. That hot spring smell is still sticking to my nose,” Muichiro laughed softly. Even though the trees provided some welcome shade, there was still too much sunlight for him to come out.

Yuichiro nodded. It was up to him to find Kotetsu, then. But luckily, he didn’t have to search much longer, as soon his ears picked up a childish voice.

“What am I going to do… it won’t last much longer like this…”

He followed the voice and peeked through the trees, finally spotting a young boy wearing a red vest and one of those Hyottoko masks the other smiths wore. He was fussing over something, a tall figure with long hair in-

Yuichiro’s breath caught in his throat. For a moment, his blood chilled and his heart raced. Three pairs of bright yellow eyes flashed through his mind.

No… it can’t be…!

But then he looked closer, and the fear slipped away. The figure had long, wild hair in a ponytail, but it was brown, not black, with a tinge of red. The clothes were different, and most importantly, it had six arms, doll-like joints showing it wasn’t alive. Even its face was doll-like and cracked with one of its two eyes on the verge of falling out.

So this was the training doll? Its resemblance to Kokushibo was disquieting. Yuichiro stepped out from behind the trees to approach the boy who had yet to notice him.

“You there, are you Kotetsu?”

The boy yelped and jumped up, spinning around and staring at him in shock. “Wah! Wh-Who are you?”

“Yuichiro Tokito, the Mist Hashira,” he introduced himself, standing tall. He still didn’t answer his question, so he repeated, “Are you Kotetsu?”

“Y-Yeah, I am,” the boy finally responded. “What do you want? I’m busy.”

Yuichiro felt his eye twitch; he didn’t like this kid’s tone. “That thing behind you, is that the training doll that can fight like a swordsman?”

“Ugh, they told you about that…” Kotetsu grumbled, lowering his head. “Yeah, it is… but you can’t use it!”

“Excuse me?”

“It… it’s going to break if someone like you uses it!” Kotetsu explained, sounding on the verge of tears behind his mask. “So I won’t let you! I won’t give you the key!”

Key? So the doll was operated by a key? But more than that, the boy’s explanation made no sense. “That’s what you’re worried about? It’s just a piece of training equipment. So what if it breaks? That's what it's there for. Just fix it afterwards.”

“No, it’s not! It’s not just a piece of equipment! But I don’t expect someone like you to understand!”

What the hell was that supposed to mean? Yuichiro was definitely getting angry now. For the next several minutes, the two argued back and forth, Yuichiro trying to get the key and Kotetsu adamantly refusing. Throughout it all, the Hashira’s temper built up more and more.

“Just go away! I told you, I won’t let anyone use it!”

But Yuichiro had had enough. He did not just go through one of the worst missions of his life for some brat to try and tell him what to do! He reached out and grabbed the kid by his shirt, pulling him off his feet and holding him up face to face. Kotetsu yelped in surprise and fear.

“Yui?” Muichiro spoke up, no doubt worried about the noise, but Yuichiro didn’t answer. He glared into the eyes of the mask.

“Listen here, you little-”

“Stop it! What are you doing?!”

A familiar voice shocked Yuichiro to his core, and he dropped the boy. Kotetsu landed hard on the ground, and Tanjiro ran up to help him to his feet.

Yuichiro stared in disbelief. “Tanjiro, you’re awake…?”

The last he’d heard, the boy had still been in a coma. Yuichiro felt relieved to see him awake, but also mortified that Tanjiro had seen him lose his temper in such a way.

Tanjiro stood up, looking at him with worried eyes. “Yuichiro, what’s going on?”

Yuichiro glanced towards the training doll. Tanjiro followed his gaze, and his eyes went wide, a gasp leaving him. “What’s that?”

“A training doll. It’s used as a sparring partner for improving swordsmanship,” Yuichiro explained. “Except this kid’s not letting anyone use it.”

He eyed Kotetsu, who looked away with a huff. “I’m not some kid; my name’s Kotetsu! And I told you, it’s going to break if you use it!”

“And I told you to just fix it if it does! Or what, are you not good enough to-”

“Alright, that’s enough,” Tanjiro put himself between the two of them, hands raised in a placating gesture. “Let’s all just calm down and talk this out. Kotetsu, Yuichiro might have been a little mean about it-”

“Hey!”

“-but he does have a point. If the doll breaks, can’t you fix it?”

Kotetsu didn’t respond. His body was tense as he looked away, but both slayers could see that he was shaking.

“Kotetsu?” Tanjiro asked again. “Why are you so worried about it breaking?”

“…Because… because you’re right. I can’t fix it if it breaks; I don’t know how.” Kotetsu admitted in a voice choked with tears. “My dad could fix it, but he’s…”

“I see…” Tanjiro said with an empathetic expression. Yuichiro looked away, suddenly feeling bad about giving the kid such a hard time. He stopped listening as Tanjiro continued to talk to the boy, lost in his own thoughts. Why was it so hard for him to just be nice to people? The fact that he had gotten so angry at and even threatened a ten year old kid was shameful.

As Yuichiro dwelled on his actions, Tanjiro and Kotetsu seemed to come to an understanding. “So, how about it?”

“O-Okay…” Kotetsu finally relented and took something from his vest pocket, handing it to Tanjiro. The older boy smiled gratefully.

“Thank you!” He stood up and turned to Yuichiro, holding the key out with a smile. “See? Here you go!”

“Um, thanks…” Yuichiro took the key, trying and failing to meet Tanjiro’s gaze. Shame burned his face; why couldn’t he be more like Tanjiro, kind and patient? Instead of being like himself… Yuichiro shook his head to drive away those thoughts. “So what are you doing here, Tanjiro?”

“Oh, me? I’m here to see Mr. Haganezuka about my new sword.”

“That’s the swordsmith who tries to stab you whenever you break your swords, right?”

“Haha, yeah…” Tanjiro laughed sheepishly.

“So did he decide he had enough of you, then?”

“Um, well, I hope not… But besides that, I also came here to ask a favor of him.” Tanjiro reached into his haori and pulled something out. In his hand was a tsuba shaped like an orange flame. “I want him to put this on my new sword.”

Yuichiro suddenly felt like he’d been struck by lightning. His breath caught in his throat as he stared numbly at the familiar tsuba. “Why… Why do you have that?”

“Huh?”

“That’s Kyojuro’s… Why do you have it?!” Yuichiro’s voice rose higher, ending in a snarl as he demanded an answer.

“I… Rengoku gave it to me, when he…” Tanjiro trailed off, seeming to realize that explaining would only worsen the situation. And he was right. Yuichiro felt his anger rising again, a fire that blocked out everything else.

“Give it to me…!” he said with a hiss.

“Yuichi-”

“I said, give it to me!” Yuichiro reached for the tsuba, but Tanjiro stepped back. “You don’t deserve it; you couldn’t even keep him safe!”

“Yuichiro, I-”

“Shut up!” The Mist Hashira lunged forward, left hand wrapping around the sword guard. But Tanjiro held firm, not letting go, and a brief tug of war took place as Yuichiro tried to wrest it away. A part of him knew he was being unreasonable, but the greater part didn’t care. The sight of the tsuba brought a bitter jealousy surging up from the depths of his soul. But amidst the struggle, a sudden pain ran through Yuichiro’s arm, and he cried out.

“Huh? Yuichiro, are you hurt?!” Tanjiro let go of the tsuba in his surprise, stepping closer to check on the younger boy. “Please, let me-!” And then a hand collided with his neck, and he fell over, hitting the ground with a thud.

Yuichiro breathed heavily as he clutched the tsuba in his left hand and stared down at his right. He hadn’t even consciously done it; he just saw red and lashed out. Lashed out and hurt one of the only people he could consider a friend. What the hell was wrong with him?

He looked down at the tsuba again, his hand shaking. Kyojuro… is this how Kyojuro would have wanted him to act?

“Yui? What’s going on out there?” Muichiro called out, sounding worried.

Yuichiro couldn’t answer. He looked at the unconscious Tanjiro, then turned his gaze to Kotetsu, who flinched back as if expecting to be struck next.

“I…” He couldn’t do this. The tsuba was too heavy in his hand. He tossed the guard at Kotetsu, who fumbled a bit before catching it.

“…Take it, I don’t need it.” He didn’t deserve it either, not with how he was acting. Kyojuro would be ashamed of him. Anger boiled ineffectually with no outlet. None except…

Key in hand, Yuichiro approached the doll. Tanjiro had gotten this key for him; the very least he could do was use it.

—

In the end, Yuichiro found the training doll underwhelming, which only made him angrier and guiltier that he had acted the way he did to get it. As night fell, he returned to their room at the inn to rest, dropped Muichiro’s basket in the corner, and went to lie down on his futon. A cloud of mist drifted towards him, and Muichiro reformed to look down at his big brother with worried eyes.

“Yui, what happened today?”

Yuichiro looked away, not saying anything. “Yui? Please, look at me. You can’t keep everything inside like this. Talk to me. Tell me what you’re feeling…!”

Nervously, Yuichiro looked back. Muichiro’s eyes had changed to teal irises and round pupils, a mirror of his own filled with tears. He swallowed the lump in his throat.

“I… I’m not a good person.”

Muichiro was silent for a moment. He laid down beside his twin and wrapped an arm around his chest.“You are,” he whispered. “You’re just in pain.”

“That’s not an excuse, and you of all people know that.” Muichiro flinched, and Yuichiro looked away, the guilt growing stronger. “I hit Tanjiro. He didn’t do anything to deserve it, but he had Kyojuro’s tsuba, and I…”

Muichiro looked surprised at the mention of the tsuba, but soon a determined expression crossed his face. “Yui, look at me.”

Yuichiro grimaced and reluctantly turned over, both twins laying side by side and facing each other. Muichiro’s frown deepened, and he pulled himself closer with the arm draped over his brother. “Why are you always so hard on yourself?”

Yuichiro sighed. He knew a conversation like this would come sooner or later. “I have to be. I’m not strong the way you are, Muichiro. I have to make myself keep going however I can.”

Even if it meant training until he was too exhausted to dream. Even if it meant burying his fear and grief deep down in his heart. He had only one goal: to make Muichiro human again. Everything else, including himself, was secondary to that.

“There you go about being strong again. You’re plenty strong, Yui. You wouldn’t be a Hashira if you weren’t, and I don’t just mean physically. Someone with a weak mind and heart wouldn’t be able to handle the things we see. The things demons do to humans.” Muichiro’s eyes darkened. Yuichiro could think of a number of horrific missions he might be recalling, gruesome scenes that haunted their nightmares.

“I can handle those because I have you with me,” Yuichiro said, grabbing Muichiro’s other hand and squeezing lightly.

Muichiro smiled sadly and chuckled. “You think so? I could say the same to you; having you at my side gives me the strength to keep fighting. You’ve trained so hard and fought so many awful demons for my sake. You make me want to keep working hard, too!”

“You really think that…?” Yuichiro asked, feeling his face heat up. He suddenly remembered what Sanemi had said months ago, about him being Muichiro’s hero. A part of him felt happy to hear his twin say that, but another part kept trying to squash that feeling. He was the older brother; he should be the one comforting and cheering up Muichiro, not the other way around.

“I do think that, with all my heart!” Muichiro nodded, his smile becoming wider as if just talking about his big brother made him happier. “You always support me, and as your twin, I want to support you too! Because we’re two halves of a whole, and we’re at our strongest together.”

Yuichiro looked wide-eyed at his brother. That was true, wasn’t it? He even remembered believing that himself once. But at some point, he had forgotten that. When did his heart begin to waver? When did all these old insecurities rise back up to strangle his faith in himself? He wanted to feel like an equal to Muichiro, but it was so hard for him to believe that he was.

“I'll always be by your side. Whenever you think you’re weak, I’m going to be right here to tell you that you’re strong,” Muichiro assured him, eyes shining with resolve.

Yuichiro couldn’t find the word to speak. He’d said something like that himself, hadn’t he? Another reversal of their positions.

But he was ashamed to find that Muichiro’s attempts to support him were only making him feel less worthy of that support. Because Muichiro’s heart held such boundless kindness and understanding, in a way that Yuichiro’s heart just couldn’t. Physically, they were stronger together, but mentally and emotionally, Yuichiro couldn’t compare. He couldn’t help a sardonic chuckle at the realization. “You really are something, Mui. A true chosen one.”

“Eh?” Muichiro tilted his head. “Chosen one?”

“I mean you’re blessed by the gods. You have the strength and kindness to save people, to make a difference. You’re like the hero in a story, destined to do great things.”

“Well, that can’t be true,” Muichiro frowned. “If I was blessed by the gods, then why did they let me become a demon? No one would write a story where a demon is the hero…”

“Muichiro…” Yuichiro felt a chill. He was only being truthful, but he worried now that he’d said the wrong thing. But then Muichiro spoke up again.

“No, that sounds much more like Nii-san,” Muichiro continued with a fanged grin. “A human who fights evil demons to save his brother, who’s become a demon himself; that would be an amazing story!”

Yuichiro was again rendered speechless. He’d never thought of it that way before. But Muichiro made him sound like someone special when he… wasn’t. He was only doing what he had to do. Any older brother would do the same… right?

“That’s what I think, anyway,” Muichiro finished, looking slightly embarrassed now. “Maybe you don’t think that, but I promise you, Yui, you’re strong enough just the way you are. You’re doing your best, and that’s all anyone can do. I’m sure our friends would agree, too.”

“Our friends, huh?” Yuichiro was suddenly reminded that this whole conversation came about because he lashed out at Tanjiro. He didn’t have many friends, and yet he kept hurting the ones he did have. Muichiro said he was good the way he was, but he wished he could change that part of himself.

As if reading his mind, Muichiro looked into his eyes and said, “Hey, Yui, let’s go talk to Tanjiro tomorrow. You want to apologize, right? So you should find him and talk to him. Though knowing Tanjiro, he probably already forgave you!”

Yuichiro couldn’t help but laugh; Tanjiro would be that kind of person. But Muichiro was right. He did want to apologize, and maybe if he did, he could start to feel worthy of the absolute faith Muichiro had in him.

“Yeah, I’ll talk to him tomorrow,” he decided. Whether Tanjiro had forgiven him or not, Yuichiro would make things right between them.

Chapter Text

Yuichiro did not apologize to Tanjiro the next day. Or the day after. Or the day after that.

It wasn’t that he didn’t want to, but when he sought the older boy out, he found Tanjiro engrossed in training with the doll, with Kotetsu acting as his instructor. Well, training might have been too kind a word; fighting for his life was more accurate. Those two months of resting in bed hadn’t done his stamina or reflexes any favors.

But every day for a week, Tanjiro was out practicing with the doll, and by the time he returned to the inn, he was dead tired, so Yuichiro couldn’t find a chance to speak with him. And with each passing day, he felt more and more unsure about even trying to apologize. Only Muichiro’s encouragements kept him from giving up entirely. So he occupied his time with training his body and sparring with his twin, hoping that an opportunity would present itself eventually.

But before that could happen, he received the news that his new sword was ready to be picked up. It was late at night and all he knew was that Kanamori had his sword in some shed out in the forest, and that he was there with Tanjiro’s swordsmith, Haganezuka.

“This is great!” Muichiro smiled after the messenger left. “We can go talk to Tanjiro and all of us can go look for your swordsmiths together! And then you’ll be able to apologize!”

But Yuichiro was still nervous. Tanjiro was impossibly kind, but even his kindness had to have limits, right? No matter how much he told himself he was being paranoid and that Tanjiro wasn’t the type to hold a grudge, he still worried.

In the end, Muichiro practically dragged him up to Tanjiro and Nezuko’s room. He lightly tapped on the wooden frame, but there was no response. Quietly sliding the door open, he peeked inside, and gave a soft, delighted gasp at the sight of the Kamado siblings curled up together and fast asleep.

As Yuichiro peered in as well, Muichiro’s body turned to mist. The older twin watched him creep into the room, confused. But his confusion didn’t last long as the cloud closed in on the siblings and brushed against Tanjiro’s nose.

Tanjiro’s peaceful breathing halted as his face scrunched up, and then he let out a loud sneeze. Nezuko jolted awake in his arms, and the mist retreated to Yuichiro’s side. Muichiro reformed himself, laughing at his own childish prank.

Yuichiro shook his head but couldn’t keep the amused smile off his face. “You’re such a kid…”

“Yuichiro? Muichiro?” Tanjiro blinked, still waking up. “Did you just tickle my nose?”

“Uh-huh!” Muichiro nodded shamelessly and stepped inside the room.

“Your reflexes are pretty slow, huh?” Yuichiro said as he followed behind.

“Nu-uh! If you had done it out of animosity, I would have sensed it!”

“I wouldn’t tickle your nose out of animosity, though,” Muichiro chuckled. Then his attention turned to Nezuko, who ran up to him in her toddler form, begging to be picked up. The other demon was happy to oblige, lifting her up to face level. “Hi, Nezuko! It’s been a while!”

“I heard you two kept Nezuko company while I was asleep,” Tanjiro spoke up. Muichiro nodded, and his smile brightened. “Thank you; I really appreciate it!”

“You don’t have to thank us; you’re our friends and we’re happy to help! Right, Nii-san?” Muichiro asked, suddenly putting all attention on him. Yuichiro froze.

“U-Um, yeah, that’s right…” he muttered lamely. Muichiro’s smile fell and he looked thoughtful, before his face suddenly lit up.

“Hey Nezuko, how about you and I go outside? We can sit on the roof and look at the stars!”

Nezuko’s eyes sparkled, and she nodded her head vigorously. Muichiro laughed as half his body transformed, letting him hover in the mist. He kept her securely in his arms as he floated out the window and up to the roof. And then the two demons were gone, and it was just Yuichiro and Tanjiro in the room. Dread curled in Yuichiro’s gut upon realizing this. His brain hurled silent curses towards his brother as Tanjiro turned to face him.

“Do you want to sit down?”

Yuichiro nodded and knelt across from Tanjiro. The older boy gave him an easygoing smile.

“So, what did you want to talk about? I know you’ve been trying to talk to me all week, and I’m sorry if it seemed like I was ignoring you! It’s just that my training was really intense, so I was really tired afterwards and-”

“You don’t have to explain yourself; I understand.” Yuichiro stopped him before he could keep going. But then the air between them was filled with an awkward silence as he struggled to find the right words. Tanjiro waited patiently for him to speak, which only put more pressure on him. After a while of thinking, he finally decided to tackle the business part of why he was here first. “I was wondering if you knew where your swordsmith was.”

Tanjiro tilted his head, confused. “Why do you want to know that?”

“My new swordsmith, Kanamori, is finished with my sword, but I don’t know where he is. I only know that he’s out in the forest with Haganezuka.”

“I see,” Tanjiro nodded, then smiled. “Well, I don’t know where they are, but we can go look for them together! It’ll be fun, and it'll give us time to catch up, too!”

Yuichiro stared, dumbfounded. Even after all this time, he was still surprised by Tanjiro’s good nature. It was as though Yuichiro hitting him and knocking him out wasn’t even on his mind. “…Um, Tanjiro…?”

“Yes?”

“I… about the other day-”

The door behind them slid open.

—

The sky was clear tonight, and a myriad of stars painted the nighttime canvas. Muichiro smiled wide as he pointed out a set of stars and traced a claw along each one, forming a picture in his mind.

“Look, Nezuko! You can see the Big Dipper! See, it goes from here… all the way to there!”

Nezuko grunted in acknowledgement. “Hmph!”

“Did you know that it’s actually part of a bigger constellation? Nii-san told me about it before.” He pointed again. “See, if you connect these stars all together, it actually makes a bear!”

“Hmm…” Nezuko tilted her head, not really seeing it. Muichiro couldn’t blame her; constellations were very abstract. He missed cloud watching; it was so much easier to create his own stories out of the clouds and get other people to see what he was seeing.

“Well, what do you see?” he asked her. Nezuko hummed and studied the sky, then pointed not at the stars, but the moon shining bright overhead.

“Huh? Oh, yeah, it is pretty tonight, isn’t it?” Muichiro followed her gaze and leaned back. It was only a crescent, but its glow was bright and clear. Since the moon was the only thing Muichiro ever got to see in the sky, he thought that the luster of it had worn off long ago. But times like this reminded him why humans thought the moon was beautiful, even with the dangers that night brought.

But even so, he longed to feel the warmth of the sun.

“Nezuko, do you want to see the sun?” Muichiro asked. “Once you’re human again?”

Nezuko blinked at him, looking for something, then nodded. “Mmph!”

Muichiro nodded back. “What would you do? I want to go cloud watching again. It’d be nice to go with you, Tanjiro, and Nii-san.”

The other demon hummed and mimed something with her hands, twisting her fingers together and then placing something on her head. But Muichiro understood, and he smiled. “You can make flower crowns now, though.”

Nezuko growled lightly, and he laughed. “Sorry, sorry, I know what you meant. There are a lot of pretty flowers that don’t bloom at night.” She calmed down, and Muichiro continued. “How about this, then? When we’re human again, we’ll find a big field of flowers, and we’ll make flower crowns for all our friends while we watch the clouds go by. And we’ll definitely bring Nii-san and Tanjiro along!”

“Mmmph!” Nezuko cheered at the idea, and Muichiro felt his heart grow light. They had a goal for after all this fighting was over, and that made him more optimistic for the future.

And then all that cheer came crashing down in an instant. A horrible feeling washed over Muichiro, the scent of blood filling his nose. This aura… it was stronger than any he had ever felt before! Kohaku, Mogura, even Muko; none of them compared to this!

Nezuko sensed it too, a guttural growl slipping past her muzzle. She couldn’t speak, but Muichiro knew the same thought was on both their minds.

An Upper Moon is here!

—

Yuichiro had no idea how this happened. One moment he was talking to Tanjiro, about to gather his courage and apologize for his behavior, and the next, there was a demon in the room. And not just any demon; even without looking at its eyes, Yuichiro could tell that this was an Upper Moon. It’s murderous aura was like nothing he’d ever felt before.

Before Tanjiro could even react, Yuichiro was already moving.

“Mist Breathing, Fourth Form: Shifting Flow Slash!”

He shot forward, aiming for a decisive cut on the demon crawling on the floor. But his sword swing met empty air; in the blink of an eye, the demon leapt to the ceiling. It was a repulsive thing, an old man with a grotesque bump on its head, made even more disgusting by its sniveling cries. But he couldn’t let his guard down; it was still an Upper Moon.

“Hinokami Kagura, Sunflower Thrust!”

Tanjiro leapt up, flames surrounding his sword as he stabbed at the demon. So this was the Hinokami Kagura, the breathing style that Tanjiro had used to defeat Upper Moon Six. But the demon dodged that attack too, dropping down to the floor.

Tanjiro landed on the ground, but before either slayer could act, the ceiling caved in. Mist poured in and something crashed down on the demon’s back. Yuichiro stared in shock as Nezuko stood up in a grown adult form, a horn emerging from her head and her pupils narrowed to slits. The mist engulfed the Upper Moon, keeping him from seeing as she lashed out with a powerful kick that tossed the demon across the room.

Tanjiro shouted something at Nezuko, but Yuichiro wasn’t paying attention. His eyes were focused on the Upper Moon as he struck out and severed its head from its neck with one swing.

“Eek! I’ve been cut!” the demon cried out in surprise. And admittedly, Yuichiro shared that surprise. This was an Upper Moon, wasn’t it? It shouldn’t have been that easy to cut its neck.

“You got it!” Muichiro reformed himself, looking shocked.

But Tanjiro didn’t relax. He looked anxiously between the two parts of the demon. “Don’t let your guards down! Upper Moon demons don’t always die when you cut their heads!”

Yuichiro gasped and looked between the demon’s head and body. To his horror, he saw bone, muscle, and skin growing from both, the head forming a body and the body forming a head. In the span of a few seconds, one demon had become two.

“I’ll handle this one!” Tanjiro shouted, running at one of the regenerating demons with his sword raised. Yuichiro turned his attention to the other one, and Muichiro burst back into mist. The older Mist Hashira tightened his grip on his sword and lunged, aiming to strike before it could fully recover. But he wasn’t fast enough. The demon raised a large leafy fan and swung it in his direction.

For a moment, the world stilled.

And then a huge gust of wind sent Yuichiro flying. The building around them exploded from the force of the gale, tossing him out into the open air. Muichiro’s mist scattered, blown to the winds. Nezuko dug her claws into the floor and caught Tanjiro before they both could be blown out as well, and Yuichiro distantly heard Tanjiro call out his name as he was thrown further and further away.

Yuichiro cursed as he realized what happened. He’d been caught by a sneak attack and thrown clean out of the battlefield. He hadn’t even seen it coming; if it had been a more lethal attack, he’d be dead now! Soon he stopped flying and gravity reasserted itself, but Yuichiro was well trained in dealing with long falls. He launched a technique that slowed his descent and allowed him to land unharmed in the forest. Damn it, how far had he been thrown?

But there was no time to think about that; he needed to get back as soon as he could. Tanjiro and Nezuko were still fighting two Upper Moon level demons, and Muichiro would be out of commission for a few minutes until his mist could reform.

As he took off, sprinting through the forest, Yuichiro heard a familiar voice cry out. He looked to his right and spotted Kotetsu, frantically swinging a sword against some thing that looked like a giant  fish with human arms and legs. It was so absurd-looking that he had to stop and stare, but then the fish monster roared and pounced, the kid only just managing to get out of the way, and he snapped back to reality.

In the blink of an eye, Yuichiro lunged, slashing through the fish’s head in one swing. No matter how annoying he was, he couldn’t just let the kid die. But the fish didn’t dissolve like it should have; its flesh bubbled and the head started to reform. That was when Yuichiro’s eyes turned to the large pot that seemed to be growing from its back. Gross. But that had to be the weak point. He slashed through the pot, and the fish monster cried out and collapsed, disintegrating on the spot.

“Wahhh! Thank youuuu!” Kotetsu sobbed, suddenly wrapping Yuichiro in a hug. He groaned and tried to get him off.

“Let go of me!”

But Kotetsu wasn’t listening. “I’m sorry I called you a seaweed head! Please forgive meeee!”

Seaweed head? But Yuichiro decided he didn't really care. He finally shoved him off and started to walk away. “I don’t have time for this. It’s not safe here. Go and find somewhere to hide.”

“Ah, wait! You have to help Mr. Kanamori! He’s in danger, too!”

Kanamori? Yuichiro looked down at his sword. He’d taken it from the training doll, and though it sufficed for practice, the blade was badly chipped and dulled from lack of care. The situation was urgent, but if he was going to have any chance of surviving against an Upper Moon, he needed his own sword. He turned to Kotetsu. “Take me to him.”

Sorry, Mui. I hope you can manage without me for a little while longer.

—

In the time it took Muichiro to pull himself back together, the situation had escalated drastically. His brother had been launched out into the forest, Tanjiro was nowhere to be found, and there were not two, but three demons where the feeble-looking Upper Moon had once been.

The red-eyed demon seemed to be giving commands to the others, angrily berating the green-eyed demon with the fan as he grappled with a furious Nezuko. And further away, Genya - when had he gotten here? - was in a struggle with the new blue-eyed demon. Genya fired a loud shot from an unfamiliar weapon, but the demon dodged and retaliated with a spear that impaled him through the torso.

Muichiro gasped and rushed in to help. His mist surrounded the blue-eyed demon, catching him by surprise and forcing him away from Genya. Taking advantage of the distraction, Genya raised the weapon again and fired, taking off the demon’s head in one blow. Muichiro reformed and turned to him, paling at the amount of blood soaking into his clothes where the spear was still lodged.

“Genya! Don’t move- !” Muichiro heard a sound, and then his body suddenly seized up as electricity coursed through it. He saw the red-eyed demon glaring at him, and Muichiro glared back before bursting into mist. He flowed past the demon and reformed, lashing out with his claws, but the demon slammed his staff on the floor and forced Muichiro to dodge as a bolt of lightning crashed down between them.

“Oh hey, you’re back!” The green-eyed demon grinned at the sight of him, still holding Nezuko back. He stuck out a tongue with the character for “pleasure” on it. “Hey, fight me next! I bet you’ll be way more fun than this girl!”

Nezuko did not take kindly to that. She leaned back and landed an upward kick that nearly ripped his head off, before rolling and tearing off his hand holding the fan. With a swing of the fan, the demon got a taste of his own medicine as he was blasted off into the sky.

Serves him right… Muichiro rolled his eyes.

“Idiot…!” The red-eyed demon shared his sentiment, watching the shrinking figure with disdain before returning his glare to the Mist Hashira. Muichiro bared his fangs and dragged a claw up his arm, the blood bubbling up into red mist. The demon’s eyes narrowed. “A red mist… you’re the demon that Lord Kokushibo turned.”

Muichiro allowed his surprise to show for a moment before he steeled his expression again. Of course the Upper Moons would be familiar with each other, but should he be worried that one of them recognized him? The red-eyed demon scoffed and shook his head. “Why he allowed you to run free, I’ll never know…”

Muichiro grinned wryly. “I guess Teacher just likes me.”

Then he held out his arm, and the blood mist rolled towards the demon, who countered with another lightning attack. But the cloud exploded upon contact, a wave of heat and force knocking both demons off their feet. Muichiro hit the floor hard and groaned; why was his mist so flammable?

At the same time, there was a crash from behind. Muichiro looked to see Tanjiro come down on top of yet another demon, this one with yellow eyes and wings like a bird. “Tanjiro!”

“Muichiro, look out!” Tanjiro shouted. Muichiro turned to see that his opponent had already stood up, his staff electrified and raised to strike, but Tanjiro leapt past him and stopped the blow with the severed foot of the bird demon. “Cut their tongues! It takes them longer to recover!”

Muichiro nodded and slashed a claw through the demon’s mouth, spotting the symbol for “anger” on his tongue. Were these demons based on the four main emotions? The blue one seemed sad; was it Sorrow? And did that make the bird demon Joy?

Before he could think about it too much, Muichiro spotted movement behind Anger. Sorrow’s spear lashed out towards Tanjiro, and Muichiro pushed him out of the way to take the blow himself. But then Nezuko was in front of them both, swinging the stolen fan to blow both Sorrow and the still-recovering Anger away. With the path clear, Muichiro remembered Genya, still knelt on the ground and trying to stand while bleeding heavily. “Genya!”

Nezuko pursued the demons to keep them away while Muichiro rushed to Genya's side. But even at a glance, he could tell his odds weren’t good. The spear had been removed and now there was nothing to stop him from bleeding out. He wasn’t sure how he was even still alive at this point.

Genya coughed, spitting up blood. “Mu-Muichi-”

“Wait, you shouldn’t talk-!”

“Shut up and listen to me!” Genya interrupted him harshly. “This’ll sound weird, but… I need some of your hair!”

…What? “Huh?”

“I don’t have time to explain… just trust me!” Muichiro heard a cry behind him, and he turned in time to see Sorrow’s spear stab through Nezuko’s chest. Her arm holding the fan had been ripped off. He gasped, then let out a growl, rage bubbling up inside him.

“Here!” He hastily slashed a claw through a lock of his hair and tossed it to Genya, then jumped in to assist Nezuko. He formed a white mist sword - the red mist was too volatile with his friends so close - and clashed with Anger’s staff. Sorrow noticed and pulled the spear from Nezuko’s body to attack, but before he could, Nezuko growled and splashed the blood from her severed arm over both demons. Muichiro panicked and jumped back as the blood erupted into pink flames that swallowed them both. He was not at all keen to get caught in those flames again, but it gave him an idea.

Two shots rang out, taking out the burning demons’ heads. Muichiro turned, and his eyes widened as he saw Genya standing. His wound had stopped bleeding - no, it had closed, regenerated. His sclera were a dark teal like Muichiro’s own, his irises and the tips of his hair were bright yellow, and the large fangs in his mouth were unmistakable.

“Genya?” Muichiro was stunned, unable to say anything else.

“Don’t worry about me, I’m fine,” he growled. “We need to take these guys out all at once.”

Muichiro still didn’t understand what was going on, but now wasn’t the time to worry. He looked over to see Tanjiro clashing with Joy, then looked up in time to see Pleasure return to the fight, leaping into the sky with his fan raised. Muichiro turned to Genya. “I have an idea! Get them all close together!”

Then he leapt into the air, aiming for Pleasure as he descended towards them. The green-eyed demon looked surprised as Muichiro closed the distance faster than he expected, and before he could attack, Muichiro’s mist sword stabbed through his chest. Both their momentums came to a stop, and the two crashed to the ground below. Muichiro’s grip tightened and the mist sword turned red as he pulled it out and stabbed it through Pleasure’s tongue.

He looked back as Genya roared and threw the still regenerating Sorrow out of the inn. It seemed his new demonic appearance wasn’t just surface level, as he had managed to overpower and impale the demon with his own spear. On Tanjiro’s end, Joy let out a destructive blast of sound towards the slayer. He ran from the attack, looking for an opening, and got it when a red mist beast ripped through one of Joy’s wings. As the demon struggled to stay airborne, Tanjiro jumped and stabbed his sword through his mouth, his added weight driving Joy down into the dirt.

“Genya! Help Nezuko!” Tanjiro shouted to the teen. Genya nodded and raised his weapon towards Anger, who was locked in a fight with Nezuko. He fired a shot that hit Anger in the back, and Nezuko grappled him over the edge. As they crashed to the ground, Anger lost what little patience he had left.

“Enough!” Lightning traveled through his staff to electrocute Nezuko as he kicked her off. At the same time, Sorrow summoned another spear to force Genya back, Pleasure swung his fan to blow both the red mist and Muichiro away, and Joy retook to the air on regenerated wings. All four were recovering quickly, but Muichiro wasn’t deterred. White mist began to gather around him.

“Nezuko!” He looked to the other demon, slowly getting back on her feet. She turned to him and nodded, understanding in her eyes. Good.

Muichiro turned back to the four emotion demons. He closed his eyes and breathed deep; the mist grew thicker, a sword reforming in his hands. Teal marks crawled across his skin. And then six eyes opened, staring through to the very muscles and organs of his enemies.

“Mist Breathing, Fifth Form: Sea of Clouds and Haze!”

Muichiro lunged forward. A sea of mist followed him as he aimed for Pleasure first, slicing off the demon’s hand holding the fan and then slashing through his mouth. Without stopping, he changed directions and sliced through Anger's and then Sorrow’s tongues in two clean motions. Joy tried to fly away, but Muichiro was faster. As soon as the muscles in his wings twitched, he was on him, jumping and stabbing his sword through the demon’s mouth, sending them both back to the ground. Then just as quickly, he was gone. White mist engulfed the battlefield as Muichiro leapt clear of the fog and turned to his companions. “All of you, get back!”

Tanjiro and Genya seemed to understand, retreating as Nezuko sliced her arm and threw a spray of blood into the mist. The blood ignited, and the cloud went up in a massive inferno of pink flames around all four demons. Nezuko put herself between Tanjiro and Genya to shield them, and Muichiro leapt back as the fire roared and a wave of intense heat washed over the battlefield.

The blaze burned brilliantly, but it soon ceased, exposing the blackened field. Muichiro could make out four charred lumps where the demons once stood, which were slowly but surely regenerating despite the immense damage done to their bodies. This Upper Moon’s regenerative abilities were truly terrifying.

The red mist rose up instinctively, ready to feed on its prey, but Muichiro found himself hesitating. The last time he ate a Demon Moon, he nearly lost himself to the power of Muzan’s blood. And that was only Lower Moon Six, the weakest of the Moons. What could happen if he ate an Upper Moon? But the demons were healing by the second, and looking at them now, something didn't feel right. They felt insubstantial, like shadows. Would beheading them all at once even work? This was the only way he could be sure to kill them.

Besides, Yuichiro was surely on his way back. Muichiro had faith that his brother would stop him if the worst came to pass.

He breathed in, preparing himself, only to stop when a strange smell reached his nose. It smelled like… fish? But underneath it was the scent of blood. He hadn’t realized until now, but the explosion had cleared the air of the hot spring’s sulfur smell that clogged up his nose. Muichiro stretched his senses as far as they could go, and that’s when he felt it. An aura of bloodlust, distinct from the Upper Moon they were fighting now, but so very similar. Dread curled in his stomach.

A second Upper Moon, out in the forest with-

“Yui!”

—

“We’re almost there! The shed is just up ahead!”

Yuichiro held his tongue, knowing that whatever he was going to say would end up coming out crueler than he intended. But he couldn’t help being frustrated; even if he needed his new sword to fight effectively, it was taking far too long to get it.

With Kotetsu’s guidance, he’d found Kanamori and rescued him from another one of those fish monsters. But the swordsmith didn’t have his sword, which was still in the shed where Haganezuka was working. Thus he now needed to go there and make sure Haganezuka was safe before he could return to the fight.

“We’re in luck!” Kanamori continued. “I don’t see any of those fish monsters-”

Yuichiro sensed something, a shudder running through him. He grabbed Kanamori’s shirt in one hand and held out his other arm to stop Kotetsu, who crashed into him and groaned.

“Ow… what did you do that for?”

“Quiet,” Yuichiro commanded. “There’s something here.”

Something powerful. It was the same feeling he got from the Upper Moon at the inn. He drew his sword and waited.

And then something rolled out onto the path they were traveling on. A pot, ornately painted with flowers and vines. It hopped on its own, and a sound came from inside.

“Oh, so you noticed me? Then you must be a Hashira!”

Something emerged from the pot with a sickening sound; it was clearly a demon, but by far the strangest one Yuichiro had ever seen. It was a twisted mockery of a human from the torso up, with multiple pairs of baby-sized arms and its eyes and mouths - it had two of each - swapped in the wrong positions. But in its eyes were a set of unmistakable characters: Upper Five. Yuichiro’s blood ran cold.

A second Upper Moon. There was a second Upper Moon in the village.

It had taken a Hashira and three other slayers to kill Upper Moon Six. He was alone against Upper Moon Five. His grip on his sword shook as despair crept in.

Kyojuro, is this how you felt? Did you know from the start how outmatched you were? Did you know you couldn’t win?

Yuichiro shook his head and scowled. No, he couldn’t lose heart now! He still needed to get back to Muichiro!

“I wonder what it is that you’re hiding in this shed? Hyo hyo!” the morphed demon laughed. Just the sound of its voice got on Yuichiro’s nerves; he stopped shaking and his grip on his sword tightened.

“My name is Gyokko, and… hmm? Something about you seems familiar…” The demon’s two mouths frowned, and its mouth eye narrowed, before all three somehow grinned. “Ah, I know! You must be the twin brother of the demon Lord Kokushibo turned!”

Yuichiro stiffened; he hadn’t heard the Upper Moon One’s name in so long. But more than that, he was instantly set on edge by the mere mention of Muichiro by this demon. And how did it recognize them?

Gyokko’s grin widened. “I knew it! You have the same withering glare! The resemblance is uncanny!”

“Shut up,” he growled, a bad feeling creeping down his spine. He didn’t want to think about what that could mean. But the demon ignored him and kept talking.

“Oh, but this presents a conundrum. Lord Kokushibo would be quite displeased if I were to kill you…” Gyokko lamented. Then he smiled and clapped his hands together. “How about I show you my art instead?”

“Art?” Yuichiro didn’t want to have any sort of conversation with this disgusting demon, but he couldn’t help asking.

He really should have, though. Gyokko laughed in delight. “I’m so glad you asked!”

He clapped his hands again, and a pot appeared out of nowhere. Something began to emerge from inside, and Yuichiro expected some sort of monster, but what he got was so much worse. A macabre display of human bodies, twisted unnaturally around each other, sprouted from the pot like a grotesque tree. They were swordsmiths from the village, their masks broken and swords stabbed through their flesh. The blood was fresh, their limbs twitched, and perhaps it was a trick of the moonlight, but their eyes still seemed to hold some life in them.

Gyokko was going on about something, and Kanamori and Kotetsu were crying behind him, but Yuichiro didn’t register any of their words. What the hell was this? Even the water demon, inhuman as it was, had a reason behind wearing a human’s skin. Even Akane, sadistic as she was, had a goal to kill for. What reason, what goal could there be to justify this? There couldn’t be one, at least not any sane one; it was cruelty for cruelty’s sake.

And then Gyokko grabbed one of the swords and twisted it, and the swordsmiths screamed, blood spouting out the eyes of their masks, and the demon seemed to find it so comical, laughing at their agony. Whether they were alive and suffering or dead and moving on reflex didn’t matter; Yuichiro couldn’t stand to see another second of it.

In the blink of an eye, he was in front of the Upper Moon, sword swinging at his neck. But he wasn’t fast enough; the demon slipped into his pot in one fluid motion. He heard a strange sound, and looked up to see another pot on the roof of the shed, just before Gyokko rose out of it.

“Now, now, at least wait for me to finish explaining!” Gyokko chided him. “You see, what I’m most proud of is my pot’s…”

The urge to shut the demon up was almost too much to resist, but before Yuichiro could move, his rational mind caught up to him. What was he doing? This was an Upper Moon; he couldn’t afford to attack so recklessly! Gyokko was still monologuing to himself, and he suddenly remembered the swordsmiths who accompanied him. He turned, finding them right where he left them.

“What are you doing? Get out of here!” he hissed.

“Huh?” Kotetsu said, still in tears. “But what about you-”

“You’ll just get in the way, so go!” Then he turned back to the Upper Moon with a glare. The first pot was still on the ground, and Yuichiro got an idea. He picked up the empty pot and took aim.

“This symbolizes-” Gyokko froze as the pot went sailing past his head, a dumbfounded look on his face as he turned to watch it fly by. “…Did you just-”

Yuichiro jumped up while his attention was diverted. But again the demon noticed in time and disappeared into his pot, and as Yuichiro’s sword sliced through it, the pot quickly turned to ash. He could already tell that, unlike those fish monsters, destroying it didn’t affect the Upper Moon at all.

He turned his eyes to the ground and watched as yet another pot appeared instantly. The demon re-emerged, a scowl - multiple scowls - on his mismatched face.

“Who do you think you are, you simpleton monkey?! Throwing my beautiful pot at me…?!” Gyokko was almost beside himself with fury, fists curled and his body shaking.

“Beautiful? That piece of crap? Your taste is almost as bad as your smell,” Yuichiro snarked. This demon had to be the source of those fish monsters, because he reeked of rotten seafood. He watched Kanamori and Kotetsu run into the trees, Gyokko paying them little mind as he focused on the Hashira.

“Why you…!” Gyokko’s eyes were practically bulging out of their sockets. But then he calmed down, a malicious smile forming on his face. “…I really shouldn’t kill you, but then again, Lord Kokushibo always was a believer in survival of the fittest. So if you were to die, it would only mean you weren’t strong enough to be useful to him, anyway!”

With a grotesque sound, a pot grew out of one of his hands. Two goldfish emerged, floating through the air.

“Blood Demon Art: Thousand Needle Fish Kill!”

The goldfishes’ cheeks puffed up, an almost comical appearance that suddenly became a lot less funny as they proceeded to fire dozens of sharp needles from their mouths. Yuichiro gasped and jumped off the roof as the spot he stood was riddled with needles. But the fish kept their focus on him and continued firing, forcing him to keep running and use his sword to deflect some of the barrage.

“Blood Demon Art: Octopus Vase Hell!”

Another pot sprouted from one of Gyokko’s other arms, and large octopus tentacles emerged to block his path. One swiped at him, and Yuichiro jumped over the tentacle, letting the needles pierce it instead. He tried to cut through it on the way down, but his dulled sword merely bounced off its flesh, throwing him off balance. In the next second, another tentacle smacked him across the small clearing.

“Hyo, hyo! Maybe this will teach you some manners!” Gyokko laughed. “Brats like you who can’t respect works of art should be disciplined, don’t you think?”

Yuichiro rolled with the hit and regained his footing. His body felt sore, but thankfully nothing was broken. “You don’t have to get so defensive, all I said was that your pot was ugly. Artists should be able to take criticism, you know?”

“Ugly is not constructive criticism!” Gyokko snapped. The tentacles lashed out again, but Yuichiro jumped over them and used their springiness to kick off and propel himself through the air. The path to Gyokko was clear, and he raised his sword to strike.

But a part of him hesitated, wondering if there was more to this. If he beheaded the demon, would it die? The fact that Gyokko was dodging his attacks seemed to suggest so, but he couldn’t be sure. The other one didn't, after all. He swung his sword a second later than he should have, and Gyokko shrunk down into his pot, avoiding the swing. Yuichiro landed and turned, scanning his surroundings for where the Upper Moon would appear next.

“You don’t seem to be using your full strength,” Gyokko commented as he emerged again on the other side of the clearing, near the shed. “Could it be that you’re scared? Oh, but I dare say, you should be scared!”

Yuichiro grit his teeth and clenched his sword hilt harder, ignoring the aching in his left hand. He hated admitting it, but Gyokko was right; he was hesitating out of uncertainty of his opponent’s abilities. He had to strike decisively, or his blade would never cut the demon’s neck, and he’d never make it back to Muichiro.

“Why don’t you just give up? If you do, I might-”

Yuichiro breathed in, and put all his speed into one lunge and strike. His blade caught Gyokko’s neck, digging in and drawing blood. Then it stopped, the dull edge unable to cut any further, and Gyokko smirked.

“Blood Demon Art: Water Prison Pot!”

A pot formed in his hand, and a wave of water crashed over Yuichiro. Suddenly, he found himself upside down, water surrounding him on all sides, unable to even take a breath. The liquid felt heavier than it should have and his limbs moved sluggishly. Gyokko’s laughter on the outside sounded muffled and far away.

“Hyo, hyo, that look of dumbfounded surprise suits you!” At his goading, Yuichiro scowled, but the Upper Moon only laughed more. “Go ahead, try to hold onto that bravado! I’ve taken away a demon slayer’s greatest weapon: their breathing! There’s nothing you can do to get out!”

Yuichiro couldn’t help but test that. He poked at the watery pot with his sword, but whatever held its shape just stretched with his blade, bouncing back as soon as he stopped. Poking the top yielded the same result.

“Hmm, I could kill you right here while you’re nice and vulnerable… but I’ll be kind and give you a chance to survive. After all, I wouldn’t want Lord Kokushibo to be too upset with me!” Gyokko chuckled. Yuichiro scowled harder; he didn’t need this demon’s mercy. But then again, if the Upper Moon wanted to be stupid, he wouldn’t protest. Not that he even could, anyway.

“Besides, I’m dying to find out what’s inside that shed that you’re so desperate to protect! I wonder what it could be? Hyo, hyo, hyo!” With a final laugh, the Upper Moon sank back into his pot and disappeared, leaving Yuichiro alone in his watery prison.

Rage boiled in his gut. It pissed Yuichiro off that he was probably only alive because of Kokushibo’s favoritism towards him. But what was he thinking, taking on an Upper Moon by himself? His only hope now was to break free and find Muichiro and the others. He waited until he was sure that Gyokko was gone, then took action. With all the air that remained in his lungs, Yuichiro mustered the strength for one attack.

Mist Breathing, First Form: Low Clouds, Hanging Mist!

His sword pushed against the water pot, stretching it to its limit. But it was no use. The pot wouldn’t burst, the chipped blade too dull to cut, and soon his strength left him. He was forced to open his mouth and draw in a breath, but nothing came in except water. Seconds passed in despairing silence. Yuichiro was all alone, with no one around to help. Slowly but surely, his vision started to blur as his oxygen ran out.

Really, what was he thinking? Did he really believe that he was strong enough to defeat an Upper Moon? He’d always fought with Muichiro at his side, so why did he think he could win when he was alone? Why didn’t he run? Was it pride? Some desire to prove himself? Whatever it was, he was now dying a slow, quiet, pathetic death, and there was nothing he could do about it.

The world beyond the pot was getting dimmer. No one was coming to help. Yuichiro closed his eyes.

I’m sorry, Muichiro. I’m sorry I won’t be there to see you become human again. But I know you can do it. You’ll walk in the sun again someday. So please, stay strong…

…

“Don’t give up, Yuichiro.”

Yuichiro’s eyes snapped open. Though the world was still blurry, one thing, one person, stood out crystal clear in his mind. His eyes went wide.

Father?

The smiling face of his father looked back at him. Yuichiro stared. What was this? A dying dream? A hallucination from his oxygen-deprived brain? But the image of his father right in front of him was undeniable. And his voice, a voice he hadn’t heard in so long, was clear in his head.

“You can’t give up yet. Someone will surely come to help.”

…You… Though he couldn’t speak, Yuichiro felt his anger flare, venomous thoughts coming to the forefront of his mind. Who are you to tell me not to give up?! I’ve been fighting every day to survive since you and Mother died! Muichiro and I, we had nothing; we were barely scraping by! And even now, we have to fight for the chance at a normal life! So don’t you dare talk to me about not giving up! If I could get out, I would! But it's hopeless! I'm not strong enough...!

He didn’t know why he was yelling at a hallucination, but he was already dying, so fuck it. He glared as the vision of his father knelt down and placed a hand on the water pot. It didn’t move - of course not, it wasn’t real - but he still looked so sad.

“Don't say that; you’ve fought hard, Yuichiro. I wish you didn’t have to, but I’m proud of you.”

The anger flared hotter. Shut up, you don’t get to tell me that! You… You left us…!

“I know, and that was my fault. I’m sorry.”

Sorry doesn’t change anything! If you knew, then why did you do it? I told you it was too dangerous! I begged you to stay! But you chose Mother over us! You cared more about someone who was already dying than you did your own sons!

Father listened as he vented, silent and patient. Soon Yuichiro’s thoughts quieted, and he returned to just glaring, waiting for some kind of response, some defense of his actions. But Father just closed his eyes and smiled sadly.

“…You always were a rational thinker, Yuichiro.”

Huh? He wasn’t expecting a response like that, and it gave him pause. Father’s smile fell as he opened his eyes - those kind red eyes - and continued.

“I went into that storm because I couldn’t watch your mother suffer when there was a chance I could do something. Yes, it was dangerous, and maybe it was too late to save her, but if I could have helped her even the smallest bit, it was a risk I was willing to take. I know that doesn’t seem rational, but love drives us to act in ways that aren’t rational, because in the end, humans are beings that thrive on emotion, not reason.”

Yuichiro stared, confused. His father was admitting that what he did was stupid, so why did his explanation make his heart ache? I don’t understand…

“I think you do understand. Remember the night that the demon attacked; you threw yourself in front of Muichiro to protect him. Can you tell me why?”

Yuichiro’s eyes went wide. He never thought about why he threw himself in front of that attack three years ago. Muichiro was in danger, and he needed to protect him. That was it. Even if he died, even if he left him alone; it didn’t matter as long as Muichiro was safe. It didn’t make sense, but it was how he felt in the moment. Was that how Father felt about Mother, on the night of that storm?

Father looked at him with a knowing gaze. “That’s not the only time, either. Tell me, why do you fight, Yuichiro? You think you’re weak, but here you are, fighting anyway. Why?”

His response was immediate. Because I have to. To save Muichiro.

“And why is that? Muichiro is strong, is he not?”

He is, but… this world is cruel. And even though Muichiro is strong, even though he's chosen, the gods won’t protect a demon. So I have to protect him. He’s my twin, my other half. I’ll always protect him!

“And that is your strength.”

What?

Father went on in spite of his confusion. “Yuichiro, there’s no such thing as chosen or unchosen people. We’re all just humans, trying our best with what we have. Strong and weak are just perceptions. Every human has infinite potential for strength within their heart; all that matters is if they have something to fight for, to draw that strength out. And you already have that. You and Muichiro both.”

Yuichiro stared, wide-eyed and disbelieving. Was he really saying that? That all people - that Yuichiro himself - had infinite potential? But how could that be true? He didn't understand.

“You will, with time. I truly am proud of you. I don’t regret trying to help your mother, but… I do regret leaving you behind.”

Father… Yuichiro felt a swell of emotion inside of him. If he wasn’t still trapped in the water, he was sure he would be crying.

“Be kinder to yourself, Yuichiro. You’re so much stronger than you think.” Father looked up, a proud smile on his face. “So keep fighting. It’s not over yet.”

A furious roar split the silence. And then the image of his father disappeared as a cloud of red swept through the trees. Muichiro leapt towards the water prison, six eyes shining bright.

His claws sliced through the water, and the pot burst.

Chapter Text

The pot burst, and Yuichiro landed hard on the ground. His lungs gasped for air, coughing up the water that had gotten inside. For several seconds, he couldn’t do anything but try to breathe again, acutely aware of how close he had come to drowning.

“Nii-san! Are you okay?” Muichiro was at his side, helping him to sit up. He patted his back to get the water out, which wasn’t really helping and was actually kind of painful due to his demonic strength. Seconds passed, and Yuichiro recovered enough to speak.

“Mu…Muichiro? Why are you-” he coughed again. “Did you beat the Upper Moon…?”

Muichiro froze, and then a look of shame crossed his face. “I… I sensed another Upper Moon out here, and I panicked. I had to make sure you were safe…”

Ah… well, Tanjiro was stronger than he looked, and he had Nezuko with him. They would probably be okay. Besides, if Muichiro hadn’t come looking for him, he might be dead by now. “Hey, don’t beat yourself up about it. It turns out I did need your help after all, right?”

He chuckled, but Muichiro just frowned. He took Yuichiro’s hand in his own and squeezed tight. “Nii-san, the Upper Moons are so much stronger than any one human! So don’t think you’re weak because you couldn’t handle one alone! Remember, we’re stronger together! You and I, we’re going to win this together!”

Yuichiro just stared, at a loss for words. But before he could speak, a pot appeared in his peripheral, behind his twin. His eyes went wide. “Look out!”

He pushed Muichiro and himself to the side as several jets of water sailed overhead. The trees behind them were torn to shreds, and Gyokko’s laughter echoed as he rose from the pot.

“I thought I heard a noise out here!” He peered closer, and his eyes lit up. “Well, well, if it isn’t Lord Kokushibo’s prized progeny!”

Progeny? But Muichiro stood up, paying the demon’s words no mind. He growled, claws digging into his palms, and red mist bubbled up around him. “Let’s go, Nii-san!”

“Now, now," Gyokko chided him, "Before you get too excited, perhaps you should take a closer listen, hmm?”

The twins paused, and Yuichiro strained his hearing, his blood chilling as he heard faint screams in the direction of the village. Muichiro gasped in horror.

“Indeed! While you’re out here, those swordsmiths you value so much are under attack! And without your precious nichirin swords, the Demon Slayer Corps will be helpless!” Gyokko gloated. Muichiro snarled, the red mist roiling with anger, but Yuichiro stayed calm, thinking. He wanted to fight together with Muichiro, but how many swordsmiths would die in the meantime? Even if they did defeat Gyokko, the price might be too high. They needed to keep the village safe.

“Muichiro,” he stood up, catching his brother’s attention. “Listen to me. I’m going to go to the village and evacuate the swordsmiths. I need you to distract the Upper Moon until they’re all safe.”

Muichiro’s anger was replaced with shock. “What? But, Nii-san-”

“This is the best option we have. You’re a demon; you’re less vulnerable than I am. Someone has to go and help the village, and that needs to be me.”

Yuichiro told himself he wasn’t putting himself down; this was just the most pragmatic option. He had already lost to Gyokko once, so it was better that Muichiro fight him while he helped the village evacuate. That was all it was.

Muichiro must have understood his logic, because he swallowed his protest. He looked reluctant for a moment longer, and then the tension left his body and he smiled. “…Okay. I trust you, Nii-san. I know you’ll keep the village safe.”

It was Yuichiro’s turn to be shocked. The look in his twin’s eyes… His belief in him was absolute.

Muichiro turned to face Gyokko. “I’ll fight. I won’t let the Upper Moon anywhere near the village!”

Yuichiro snapped out of his shock and nodded. “I know you won’t.”

With one last look at his twin and the Upper Moon, Yuichiro turned and ran towards the village, hoping he would make it in time.

—

Muichiro watched his brother go, then turned back to glare at the Upper Moon Five. The blood mist spread out around him, jaws open and ready to strike.

“My, what a frightening glare you have; it gives me chills!” the Upper Moon chuckled. “And those six eyes! You’re the spitting image of Lord Kokushibo!”

Muichiro’s eyes narrowed further, looking through the demon’s skin to his muscles and organs beneath. He sounded nonchalant, but his muscles were tensed, ready to act at a moment’s notice.

“Oh, but I haven’t even introduced myself! Upper Moon Five, Gyokko! It’s a pleasure to meet you!”

Muichiro didn’t respond; he didn’t want this demon speaking his name. “How do you know Teacher?” he asked instead, hoping to get him talking and lower his guard.

“Why, we’re coworkers, of course! I’ve known him for almost two hundred years now!” Gyokko answered. “And I must say, he knows how to pick his students! The cannibal demon lurking in a blood red mist; what a terrifying picture! It gets my creative juices gushing!”

Muichiro grimaced; this demon really creeped him out. “You talk too much.”

The Upper Moon’s face fell. “How cruel, you’re just like your brother. Ah, but do you really think you can stop me without him? You’d have to eat me in one gulp, and I know what happened the last time you did that.”

Muichiro flinched. Gyokko laughed and continued.

“Just imagine, you would stop one threat, only to lose control and become an even greater danger to those humans you’re trying to protect! What delicious irony!”

The demon’s mocking laughter snapped Muichiro out of his doubts, familiar anger flaring up. “…I don’t have to beat you.” Yuichiro had only told him to distract the demon until he returned, after all. The blood mist poured forth, forming a dragon that bore down on the Upper Moon with a roar.

Gyokko smirked, and two pots formed in his hands. “Blood Demon Art: Eastern Typhoon Winds!”

The pots sucked in air, then expelled a fierce torrent of wind and seawater to blow the mist dragon away. Muichiro braced himself against the force of the gale that threatened to send him flying; it was like he was standing in the middle of a storm.

“Hyo, hyo! I thought I might encounter you one day, so I created a Blood Demon Art just for this occasion!” Gyokko explained. “These seabound winds will blow away any mist you throw at me!”

The wind slowed enough for Muichiro to regain his footing. For a moment, he glared at the Upper Moon. And then his lips turned up in a fanged smirk. “What a coincidence! I’ve been developing some new techniques in case I met someone like you, too!”

“Hm?”

Muichiro positioned his body to block the winds as a red mist sword formed in his hands. The sword elongated and branched off into multiple smaller blades.

“Moon Breathing, Seventh Form: Mirror of Misfortune, Moonlit!”

Muichiro slashed outward, and bright red misty crescents split off from his sword to travel at high speeds towards Gyokko. The expanding slashes cut through the typhoon winds and the pots generating them with ease. The winds ceased, and the mist dragon reformed, leaping at the Upper Moon. But its jaws only ripped through a few infantile limbs before the demon retreated into his pot and disappeared.

Muichiro turned his eyes in multiple directions, scanning for the demon. Then he looked up and caught a pot forming on a tree branch. Gyokko re-emerged with wide eyes and clenched teeth. “That was one of Lord Kokushibo’s techniques! How did you…?!”

“I don’t call him Teacher for nothing,” Muichiro raised his altered blade and pointed it at the demon. “And when it comes to sword techniques, I have a very good memory.”

“Impossible… When could you have…” Gyokko shook his head and grinned. “Well, I’ll admit that’s quite the trick. But can you keep it up? I can tell that red mist takes a lot of power to maintain.”

Muichiro frowned. Gyokko wasn’t wrong; he hadn’t used the Devouring Mist this much in a long time. He felt the strain as the mist siphoned his blood to sustain itself. Still, it wasn’t a problem. He willed the mist dragon to return to him, and a shiver ran through his body; the blood of an Upper Moon was potent.

But he felt his strength returning, and he grinned. “I’ll manage.”

“Will you?” And then Gyokko sprouted a new pot, pointed not at him, but at the shed, where Muichiro sensed humans inside. His grin fell as giant octopus tentacles burst out, and he rushed to throw himself between them and the building. He made it and slashed through the tentacles at the same time as they smacked him through the wall of the shed. He landed in a heap on the ground, debris and sliced tentacles all around him.

“Ah, Lord Tokito- wait, you’re Lord Tokito’s brother!” A voice called out.

“Huh? What are you talking about?” A younger voice asked. Muichiro recognized that one. He opened his eyes and saw two swordsmiths, an adult and a kid, standing over him. The kid recoiled in fear. “Ahh! Another demon!”

“No, no, this demon is Lord Tokito’s brother! He’s a Hashira, too!” the adult swordsmith quickly assured him.

“Are you Kanamori?” Muichiro asked as he sat up.

“I am! Do you know where your brother is? I have his sword here.” Kanamori held up said sword in his hand.

“He’s heading to the village. It’s under attack by demons. I need you to go and give that sword to him,” Muichiro stood back up and resummoned his blade. The two swordsmiths backed away nervously.

“U-Understood!” Kanamori nodded. “Come, young Kotetsu! And Haganezuka…!”

He stopped, and Muichiro looked to see a third swordsmith sharpening a blade. He paid them no mind and focused only on the sword despite the numerous injuries to his person. Kanamori groaned. “Ugh, there’s no way he’ll leave!”

Muichiro didn’t fully understand what was going on, but he understood enough. “Get the sword to Nii-san. I’ll protect Mr. Haganezuka.”

“Oh, thank you, Lord Tokito!” Kanamori bowed. Muichiro nodded and leapt back out to confront Gyokko. The red mist billowed around him, obscuring Kanamori and Kotetsu as they ran from the shed.

“You’re so insistent on protecting such worthless lives; it’s almost comical!” Gyokko said with an amused grin. “Why even bother? They’d be far more useful to you as food!”

“…Worthless…?” Something about that word struck a chord in Muichiro. A forgotten memory, a flash of a hot summer night, surfaced, and a terrifying rage rose up from the pit of his stomach. “They’re not worthless…! Human lives… are worth far more than the likes of you!”

The Devouring Mist howled as Muichiro raised his blade and charged.

“Moon Breathing, Third Form: Loathsome Moon, Chains!”

—

“Mist Breathing, Sixth Form: Lunar Dispersing Mist!”

Yuichiro leapt above a fish monster that had pinned a swordsmith against a wall. His sword struck out, slashing through the jar on its back, and the fish screamed as it collapsed and dissolved.

He landed and turned to the swordsmith, grimacing at the blood staining his clothes. “Can you move?”

“Y-Yes…!”

“Then run! Follow the others and head towards the forest to the south! Grab as many swords as you can!” The smith nodded and ran off as fast as he could in his condition, and Yuichiro turned to his next target. The fish monsters were everywhere, rampaging in the streets and climbing over buildings, leaving a trail of destruction in their wake.

Yuichiro ran towards a group of three that were clawing at a wall to get to some smiths on the roof. He jumped up to slice through their jars in three solid strikes, but there were still more coming. He called to the smiths to flee and charged forward again.

These fish monsters weren’t dangerous - not to a Hashira - but there were a lot of them. And even though the village was small, there was still a lot of ground to cover. Killing the monsters and evacuating civilians, injured or not, took time, time that could cost people elsewhere their lives. It was infuriating; Yuichiro was only one person, he could only do so much. He wasn’t strong enough to-

“Yuichiro, there’s no such thing as chosen or unchosen people. We’re all just humans, trying our best with what we have. Strong and weak are just perceptions.”

Yuichiro cut through another fish monster, frustration fueling his swing. What did that even mean? Someone who was weak wouldn’t just become strong out of nowhere. Some people were born stronger than others; that was reality, wasn’t it? What was his father trying to tell him?

More monsters fell beneath his blade. Maybe he wasn’t telling him anything. Those words were spoken by his dead father while he was drowning. Surely they were just the rambling thoughts of his oxygen-deprived brain. But that idea didn’t sit right with him; it felt so real. Like he was really hearing Father's voice.

This part of the village was clear of monsters and survivors, so Yuichiro ran further in where more fish rampaged, tearing down buildings and chasing after fleeing swordsmiths. Yuichiro targeted the ones attacking the smiths first, his mind continuing to race.

We’re all just humans doing our best… but some people’s best was better than others. Yuichiro could try his best, but it didn’t change that some swordsmiths had already died and more would likely follow. Maybe Muichiro could have saved them, but he needed to fight Upper Moon Five. Because Yuichiro was too weak to do that himself.

His arms were shaking; his left hand pulsed painfully from the overexertion. But he couldn’t let up now; Muichiro trusted him to protect this village! Yuichiro forced himself to move faster, to swing harder. More of the monsters fell around him, but one saw him and tried to attack from behind. Yuichiro turned, but then the fish suddenly collapsed, its pot sliced to pieces.

“Yuichiro!” A sweet voice called out. Yuichiro looked up to see Mitsuri land gracefully in front of him, a smile on her face despite the grave situation. “I came as soon as I could! What’s going on here?”

“An attack by two Upper Moons. Tanjiro and Nezuko are fighting one at the inn, and Muichiro’s fighting the other in the forest. These monsters are just minions created by a Demon Blood Art.” Nonetheless, they were a dangerous threat to the untrained swordsmiths.

Mitsuri nodded, grasping the situation quickly. “Then we have to clear out the village and help them! You’ve already got this area covered, so I’ll protect the chief and handle the monsters east of here!”

Yuichiro nodded back. “Go, I’ve got this.”

“Right! Let’s both do our best, Yuichiro!” The Love Hashira smiled and ran off, her ribbon-like sword cutting through multiple fish monsters at once. Yuichiro had to admit that he felt more at ease having her here, trusting Mitsuri to cover the areas of the village he could not. It was almost funny, how confident he could sound when speaking to her, when on the inside he doubted himself more and more.

The “conversation” he had with his father in the water pot played over and over in his head. He was trying to understand. The anger and resentment had died down, and now he was just lost.

“Every human has infinite potential for strength within their heart; all that matters is if they have something to fight for, to draw that strength out.”

Something to fight for? His mind instantly went to Muichiro. Muichiro was his reason for fighting; he’d said as much to Father himself. He forced himself to be strong for Muichiro’s sake. But that strength had limits, didn’t it?

Muichiro would say no.

Yuichiro paused. He wasn’t sure where that thought came from, but he knew it to be true. Muichiro believed in him wholeheartedly. So did Mitsuri, who trusted him to protect the villagers here, and Tanjiro, and Shinobu, and…

…The truth was, the only one saying Yuichiro was weak was Yuichiro. He was the only one who didn’t believe in his own strength.

“Be kinder to yourself, Yuichiro. You’re so much stronger than you think.”

Be kinder to himself. As angry as Yuichiro was at his father, he was still his father, and he had always taken his words to heart. Be kinder to himself. All humans had infinite potential; that included Yuichiro. Muichiro’s words came back to him.

“You and I, we’re going to win this together!"

You and I. Yuichiro and Muichiro.

Because they were two halves of a whole. And halves, by their very nature, were equal, fitting together perfectly to make something bigger than their individual parts.

He thought back to all the times he’d risked his life for Muichiro. Not just that summer night, but also when he fought and killed Lower Moon Four. When he threw himself into a raging, deadly mist to reach his brother - twice, at that. When he put himself between his twin and the most powerful Upper Moon of them all.

And when he made a promise to Muichiro, that he would always be by his side.

In the end, Yuichiro was a human, a being driven by emotion. And those moments where he cast aside reason and acted only on his desire to protect, on his love for Muichiro, those were the moments when he was at his strongest.

He wasn’t forcing anything; the power was already in him, born of his own will. Because even if Muichiro was stronger, his growing strength threatened his humanity. And that was where Yuichiro was needed; to help Muichiro remember the part of himself that was still human. He would give everything he had and more to save his brother. And nothing, not even an Upper Moon, would stop him.

“And that is your strength.”

Yuichiro understood. His love for Muichiro was his infinite strength. So he had to get back to him, to fight side by side against their enemy. And to do that, he needed to get rid of all these monsters that were in the way!

“Mist Breathing, Fifth Form: Sea of Clouds and Haze!”

Yuichiro surged forth, slashing through the monsters in front of him faster than he ever had before. His heart was beating faster and faster, and fire rushed through his veins.

There was no such thing as chosen or unchosen. Why did he put so much stock in the gods’ will anyway? What had the gods ever done for them? Not a damned thing! If the gods had forsaken his twin, then Yuichiro didn’t need their blessing. He would save Muichiro himself!

With one final swing, the last of the fish monsters fell, and silence filled the village. He couldn’t hear any more monstrous shrieks or terrified screams. He could only hope that meant he and Mitsuri had succeeded in defeating the monsters and evacuating the villagers.

No, we did succeed. I trust Mitsuri. If the swordsmiths are safe, then I need to-

A familiar roar split the air, and Yuichiro turned towards the forest. The blood mist billowed up in an ominous cloud, pulsing bright red, gnashing teeth and jaws snapping at the sky. A sense of dread rolled over him like a crushing wave.

“Lord Tokito!”

Yuichiro looked to see Kanamori and Kotetsu running towards him. The older swordsmith had a sword clutched in his hands.

Yuichiro’s eyes narrowed. He felt - no, he knew - that Muichiro was in trouble. But not from the Upper Moon.

Hold on a little longer, Muichiro. I’m on my way!

—

Gyokko knew from the start not to underestimate a descendent of Kokushibo. The human child was skilled for his age and had an irritatingly sharp tongue, but he was still just a human. But the demon, he was the one that Kokushibo himself turned. He was the one to be wary of.

“Moon Breathing, Second Form: Pearl Flower Moongazing!”

He’d seen Kokushibo’s Moon Breathing in action before, but never faced it himself. Misty red crescents flew from the child’s sword, a whirlwind of deadly blades Gyokko was only just able to dodge. But he found himself struggling to do even that, the deceptive range and speed of the crescents causing many a lost limb and errant cut.

Normally that would be of little consequence, but with each wound, each drop of his blood spilled and absorbed, the child grew stronger and faster. It was a dangerous ability, to take the strength of his opponent and make it his own. The rage and hatred driving him was felt in every burning cut. Despite his young age and refusal to eat a single human, this demon may very well be on the level of an Upper Moon.

For the first time in almost two hundred years, Gyokko had to admit he was almost in over his head. But only almost. He knew what he was doing, after all.

“You’re still not fast enough to keep up with me! You’ll need to do better than that if you want to win!”

His taunting had an obvious effect; the child’s slit pupils shrunk with fury, and he growled like a feral animal. He was getting stronger and faster, no doubt, but he was losing control. He used techniques less, often attacking directly with his claws or mist. Attacks meant only to stall or debilitate were now aiming to kill. But the reckless strikes were easier to avoid, so long as he could see them coming in time.

“What’s the matter? Don’t tell me-”

“Moon Breathing, Fourteenth Form: Catastrophe, Tenman Crescent Moon!”

Gyokko’s eyes went wide, and he only barely teleported away from the massive storm of crescent moons thrown his way. He reappeared in a tree behind the child, staring in shock at the fifty foot swath of destruction left in the attack’s wake.

What is this? There’s no way he learned such a technique from just observing it! What have you been teaching this child, Lord Kokushibo?!

The child in question turned his way. Gyokko quickly hid his shock and forced a laugh.

“Hyo, hyo! Still too slow!” Nevermind the lost limbs and cuts all over his body; those would heal soon.

More importantly, the demon child snarled, a wild gleam in his six eyes. They’d ended up quite deep in the forest, but Gyokko made sure they were slowly making their way back towards the village. The child, blinded by rage, hadn’t noticed a thing. He was just like his brother, all too easy to trick.

That’s right, just follow me. That red mist of yours will soon swallow this pathetic village whole…!

—

The fire inside roared.

This deep in the forest, there was no reason to hold back. No one to fight with, no one to protect. The Devouring Mist could rage without restraint.

Muichiro chased after Gyokko, lashing out again and again, each faster than the last. But the Upper Moon was quick, just managing to evade his claws. But only just. The contractions of his muscles betrayed a retreat, and Muichiro lunged, slicing through the wind pots and several limbs before the demon slipped away. Without the gales to hold it back, the blood mist rushed in to consume the severed parts. Strength surged through his limbs, but it wasn’t enough. The mist howled for more.

A pot appeared in his peripheral, and Muichiro slashed through it before the Upper Moon could even come out. He heard movement and jumped out of the way as a barrage of needles impaled the ground where he stood. A moment later, the fish firing the needles were sliced to pieces.

“I can see why Lord Kokushibo took an interest in you,” Gyokko called to his right. “You know, we do have a recent vacancy in the Upper-”

The blood mist only tore off a single arm before he retreated again. Muichiro growled; he was sure he could end this with one direct hit if only the demon would just hold still…!

…Huh? Why am I trying to...?

In his moment of confusion, Gyokko re-emerged from behind with a pot in each hand. “Let’s see how you handle this! Blood Demon Art: Ten Thousand Gliding Sandfish!”

He pointed the pots at Muichiro, and a massive swarm of fish poured forth. At the same time, two more pots summoned the howling typhoon gales, pushing the fish forward even faster.

There was no time to think. Muichiro jumped into the trees, darting through the branches as the fish gave chase. They ripped through the trees with reckless abandon, and the winds kept him from using his mist to destroy them. Finally, he leapt out and lunged for Gyokko directly. But the winds suddenly increased in intensity, pushing him back and leaving him vulnerable to the pursuing sandfish.

But before they could touch him, Muichiro dug his claws into the ground and screamed. The ground cracked all around him, and the cracks rapidly spread outward across the entire clearing. Gyokko froze, recognizing the danger a split second before the blood mist erupted from beneath, pouring out like a massive geyser and swallowing up him and the sandfish and everything around them.

The sanguine cloud rose high into the air, roaring towards the sky.

Breathing heavily, Muichiro stumbled to his feet. He felt thoroughly drained, the attack taking far too much energy. But the mist returned to him, and he shuddered at the feeling of the Upper Moon’s blood coursing through his veins. Consuming this amount of Muzan’s blood was painful; it ripped open a pit in his stomach that ached for more. More blood. More power.

Muichiro shook his head, trying to think through the haze of red enveloping his mind. No, stay focused! You just have to stall until Yui gets back!

A sound came from his right, and his eyes snapped to the source. A pot popped out of the ground, and Gyokko appeared. He hadn’t escaped the mist unscathed; much of his skin was missing, exposing the muscle and bone underneath. But he was still alive, and quickly returning to his original strength.

Muichiro turned to face him with a glare and a snarl slipping past his clenched teeth. Despite his efforts to stay grounded, just the sight of the demon was making the inferno inside him burn hotter.

“Heh, look at you, growling and snapping like a rabid dog… What a shameful appearance…” Gyokko taunted him, but there was a shaking in his voice that hadn’t been there before. Muichiro could see his muscles tense up and his heart beat faster.

Do you smell the scent of fear? He is afraid of you, as he should be.

The voice - his voice - echoed painfully in his mind. Muichiro growled and clutched his head in a futile attempt to block it out. He felt the hunger in the pit of his stomach.

You are stronger than him. Eat. Destroy him and take the power you deserve.

The fire inside roared. His vision turned red.

Muichiro enveloped himself in mist as he lunged at the Upper Moon. But the demon responded with a wind pot that blew him away just as his claws carved through his throat. Blood ran down Gyokko’s chest as he looked perturbed by the grisly wound. “Guh… I didn’t want to have to use this, but sacrifices must be made in the name of art!”

He clapped his hands, a pot appearing between them. Muichiro growled as something rose out of it, but as soon as he could make it out, he stopped. The overwhelming fury turned to ice as he stared up at a twisted collection of human bodies, merged together in a tree-like shape.

“What…”

He heard a crack - several cracks - and the tree of corpses split apart.

Blood sprayed across the ground and Muichiro himself as five crab-like creatures leapt at him. He gasped and jumped back, putting distance between them. He saw they were indeed crabs, but instead of shells on their backs, they wore the severed heads of the swordsmiths. They leapt at him again, pincers snapping, and Muichiro dodged away.

“Hyo, hyo!” Gyokko laughed, sounding more confident again. “You seem so concerned about not eating humans, so I wonder how you’ll fare against these? Can you bear to let your mist devour them? Hyo, hyo!”

Muichiro growled. He tried to move the red mist to attack Gyokko directly, but one of the crabs jumped in the way. His eyes widened and he pulled the mist back, wrapping it around himself. But the other crabs were still attacking, practically throwing themselves at the blood mist, and he had no choice but to disperse it entirely. He couldn’t risk the swordsmiths getting caught in it; even if they were already dead, he couldn’t let that happen.

He turned to mist and flowed past the crabs, only to be scattered by those damned wind pots. He reformed himself, but the crabs attacked as a group, corralling and forcing him back. He couldn’t attack them without potentially hitting the humans grafted to them too. One crab cut his arm and the fire rose up, the wound bubbling, but he couldn’t allow the Devouring Mist to manifest itself. The tide of battle was quickly turning against him.

Enough of this foolish charade. You know what you have to do.

It’s not a charade…! Muichiro yelled at himself. It was his principles, his very humanity! He could remain human at heart because he didn’t eat humans, alive or dead. To go against that would be…

Your half-hearted resolve accomplishes nothing. More people will die while you hesitate. You have the power to win, so use that power.

The voice’s words struck his heart like a dagger. Was that true? Was he just being selfish and half-hearted by holding himself back? He looked at Gyokko, grinning smugly like he had already won, and the rage returned, scorching him from the inside.

What kind of monster did this to humans? These Upper Moons had lived for hundreds of years and killed countless people. And for what? What was the point? These monsters didn’t deserve to exist; if he had the power to destroy them, didn’t he owe it to those who died to stop their killers by any means necessary?

He couldn’t afford to be selfish any longer.

The crabs leapt at him all at once, and Muichiro pulled his arm back, the blood mist wrapping around it and forming the head of a beast. Fire roared in his veins as he let out a scream. The mist beast charged forth, jaws open to swallow up the crabs and their human hosts.

Something moved in his peripheral, and before the mist could touch them, the crabs were cut to pieces.

Muichiro froze, the mist losing form and dispersing. The remains of the crabs fell to the ground, and someone stood in front of him, a white sword raised in his defense. As if a spell had been broken, he suddenly saw clearly.

“Yui?”

—

Yuichiro breathed a sigh of relief as he stood up straight. The crabs disintegrated around him, though the human heads remained, sliced to pieces. He felt disgusted, having their blood on his sword, but it was a necessary evil. He turned to Muichiro and grinned.

“Guess I made it in time, huh?”

Muichiro stared at him, all six eyes blown wide. Yuichiro paused, taking in his brother’s state: his body tense and shaking, his breaths heavy, and the remnants of the blood mist still curled around him. He thought back to the crabs he’d just destroyed; it was clear what Gyokko had been doing, using his promise to never eat humans against him.

It made his blood boil, but he smiled confidently for his brother's sake. “Don’t worry, Muichiro. The you that’s human… I’ll protect it, no matter what!”

Muichiro gasped. Yuichiro turned to face Gyokko, who stared back with a mix of shock and fury.

“You… you should still be at the village! What happened to all my fish?! And what is that mark?!”

Mark? Yuichiro didn’t know what he was talking about, but he didn’t grace the demon with a response. He held up his new sword, the blade gleaming in the moonlight. “Let’s go, Muichiro! We’re going to win this, together!”

“Nii-san…!” Muichiro breathed, stunned, before a confident smile to match Yuichiro’s own graced his face.  He moved to stand by his side, the red mist fading and a white blade forming in his hands. “Right! Let’s do this!”

“Well, don’t you two sound sure of yourselves?” Gyokko grumbled, but Yuichiro could hear the uncertainty in his tone. “But it won’t make any difference! You’re still not strong enough to defeat me!”

“That’s exactly what someone who’s going to lose would say,” Yuichiro grinned. Muichiro chuckled beside him, and Gyokko snarled, clearly irritated.

“Big talk for a pair of brats who have barely reached ten years! I’ll teach you both a lesson in respect!”

Pots sprouted from his hands, and a flood of razor-toothed sandfish streamed out. Yuichiro dodged left while Muichiro went right, and the fish split up to pursue them both. “Muichiro, with me!”

“Got it!”

Yuichiro jumped into the air, and his twin followed.

“Mist Breathing, Sixth Form: Lunar Dispersing Mist!”

The two streams of sandfish were sliced to pieces in seconds. Yuichiro wasn’t sure why, but he felt incredible. His speed and reflexes were at their peak; he felt like he could do anything. He landed on the ground, and Muichiro’s mist formed a cocoon around him as the pieces of fish rained down. There was a sour smell in the air as the cloud kept the blood from touching him.

A fierce gust of wind and water blew both the mist and the blood from the sandfish away. Gyokko looked smug as Yuichiro held his ground against the storm, but then turquoise eyes glowed in the tree to his left, and Muichiro leapt out, claws slicing through the pots. Gyokko teleported away, but just as he reappeared, a slash from Yuichiro forced him back into his pot. With both twins attacking, the Upper Moon could barely come out of his pot for longer than a second before having to dodge another strike. Their increased speed and coordination were too much to keep up with.

Gyokko quickly became agitated, and that made him sloppy. He emerged from a pot behind Yuichiro, preparing to attack, only for Muichiro’s mist to envelop him. In the second that the Upper Moon stumbled, blinded, Yuichiro crouched low, then surged forward to strike.

He heard Gyokko gasp, and his sword cut through something, but it didn’t feel solid. Muichiro reformed and the mist cleared to reveal the empty skin of the Upper Moon, lifeless inside his pot.

“Eww…” the younger twin stuck out his tongue. Yuichiro had to agree. He didn’t think he’d ever met a more disgusting demon than this one.

“Hyo, hyo, hyo, hyo!”

The laughter was hard to trace, but Yuichiro saw something large slither behind the trees. Both twins kept their backs to each other as they waited for their foe to show himself. Then Muichiro’s top set of eyes looked up, and he tensed. “Up!”

They jumped away as something crashed down between them. Gyokko rose up in a new, larger form. His lower body was serpentine, and his upper body was some sort of scaly fish humanoid with muscular arms and fin-like hair. He glared at the twins, eyes glowing bright.

“Congratulations,” Gyokko said with menace in his voice. “You two will now have the honor of seeing me in my true form.”

“Can’t say it’s much of an improvement, honestly,” Yuichiro said flatly. “What are you, a snake?”

“I think he’s an eel!” Muichiro shouted from across the clearing. Yuichiro shrugged, not really caring one way or the other.

“Shut your mouths, you dim witted monkeys!” Gyokko shouted before regaining his composure. “I admit I was holding back before, but that changes now. Lord Kokushibo made a mistake by allowing you to roam free; I’ll present you both to Lord Muzan myself.”

“I’d like to see you try,” Yuichiro said with a dismissive grin. “I’m feeling pretty amazing right now; I wonder if you can even touch me?”

“Good luck catching my mist, too!” Muichiro chimed in, grinning wide to show his fangs.

Gyokko snarled, thoroughly fed up with them both. “Overconfidence will be the death of you brats!”

Faster than they could blink, the demon was in front of Yuichiro with his fist raised. But despite his admittedly greater speed in this form, Yuichiro was still able to keep up. He backed away from his rapid punches before jumping into the shelter of the trees. Muichiro seemed to notice something, a look of surprise on his face.

“Huh? When did we get back here…?” His eyes lit up. “Nii-san, I’ll be right back!”

“Got it!” Yuichiro acknowledged as his twin ran off. Normally he might have worried about being alone, but he really did feel amazing. The Upper Moon seemed to move so much slower; dodging his attacks was almost child’s play.

Then he noticed the fish flopping around on the ground near Gyokko’s fist. Yuichiro felt something wet on his chest, and looked down to see part of his uniform dissolve into those same fish. What the hell?

“You seem confused. You see, everything my fists touch turns into cute little fish!” Gyokko boasted. “What do you think? Isn’t it grand?”

“I don’t think you want to know my opinion there,” Yuichiro rolled his eyes, incensing the demon immediately. “What’s with the obsession with fish, anyway?”

“Fish are more beautiful and useful than the likes of you, you worthless brat!”

“Nah, I’ve got plenty of worth. I have friends and a brother to protect, and they would do the same for me.” Yuichiro smiled to himself. “You, on the other hand… I doubt anyone will care when I cut your head off.”

Gyokko growled and lunged, but from Yuichiro’s view, he still moved so slowly. He jumped down to meet him, sword raised to put an end to this.

“Blood Demon Art: Killer Fish Scales!” Gyokko suddenly increased in speed, leaping about and striking at Yuichiro with his claws. But the Mist Hashira blocked each strike, staying calm and keeping a close eye on his opponent’s movements. Gyokko attacked from behind, but a sudden influx of white mist disrupted him.

Yuichiro smirked. “Took you long enough.”

Muichiro reformed and grinned back. “It took a little longer than I thought. Let’s finish this!”

Yuichiro nodded, and Muichiro turned back into mist that shrouded the battlefield. He made out the looming silhouette of Gyokko in the fog, and breathed in deep.

“Mist Breathing, Seventh Form: Obscuring Clouds, Despondent Haze!”

And then he disappeared, Gyokko’s fist swinging through nothing but air. The Upper Moon looked around for the twins, only for a dark shape to slip past him and cut open his arm. He recoiled, spotting glowing eyes in the mist and barely dodging another strike, just for another cut to split open his back. He backed away again, a hint of fear showing through.

“What is this? What’s going on?” Gyokko whirled around, lost in the mist, constantly spotting two visions out the corner of his eye. But whenever he struck out at one, it would suddenly vanish, and the other would dart in and strike before disappearing as well. He couldn’t even see the younger twin moving anymore, only catching glimpses of the older twin’s darker clothing like a stalking mirage. The haze swallowed everything, disorientating and bewildering.

“Hey, tell me,” Gyokko turned and saw a black haori in the mist. The Hashira approached head on, a sword held low in his hands. “What was it you said about overconfidence?”

Gyokko snarled. “Don’t underestimate me, you brat!” He lashed out, and finally his fist struck true. With a sickening sound, he punched straight through the Hashira’s chest. Gyokko grinned as he felt his fist rip through flesh and bone and burst out the back of the small body. Little fish slipped from the fatal wound.

“Got you…!” he hissed triumphantly.

The Hashira's sword fell to the ground with a dull thud. He was silent, not making a sound, long hair hiding his face. A tingling ran over Gyokko’s hand, giving him pause.

Then the boy lifted his head and smiled, showing his fangs. “…Got you.”

Gyokko’s eyes went wide and a gasp escaped him as the blood on his fist melted through his scales to the skin underneath. Said fist fell to the ground, dissolved by the red mist pouring from the wound. The dark haori turned white, and Muichiro waved as he vanished into mist.

And then Yuichiro took his place, slipping past the Upper Moon, his sword slicing through his neck in one clean cut.

Yuichiro held his stance as Gyokko’s head toppled to the ground and rolled to a halt. Muichiro reformed himself, his wound already healing, and looked down at the fallen Upper Moon. Gyokko was in utter disbelief, unable to even comprehend that he had lost. And then reality set in.

“H-H-How could this be…?! Me, lose to a couple of children?! It’s impossible! Inconceivable!”

“Can’t even have the decency to die quietly, huh?” Yuichiro grumbled as he walked up. “Dissolve faster, will you? I can’t stand listening to your slimy voice.”

“You… How dare you! I don’t care what you are to Lord Kokushibo, you’re still just a worthless human!" Gyokko turned his glare to Muichiro. "And you! You and I are chosen beings! And yet you waste your potential by lowering yourself to the level of these maggots-!”

Yuichiro rolled his eyes at the demon's insult towards him, but the second he turned his words towards Muichiro, a fierce protectiveness took hold. He caught the look on Muichiro’s face, slit pupils trembling and jaw clenched, red mist leaking through tightened fists, and decided enough was enough.

Before Gyokko could say anymore, Yuichiro raised his sword and slashed his head in half. Muichiro jumped, shocked out of his growing anger.

“…Just go to hell already.” Yuichiro growled as the Upper Moon finally crumbled away. He stepped over the remains of the demon’s body to stand in front of his brother. “Are you okay?”

Muichiro blinked rapidly and shook his head. Slowly, his tensed muscles relaxed, and when he reopened his eyes, the slit pupils were gone. He exhaled and nodded. “I’m… okay.”

Yuichiro frowned. He wondered just how much of the Upper Moon’s blood his twin had consumed. But the demon was dead now; the battle was over. The inexplicable strength left him, and he stumbled, suddenly feeling exhausted. Muichiro immediately moved to support him. “I’m fine, Mui. I can stand.”

“Are you sure you’re okay, Yui?” His twin turned his question back on him. But this time, Yuichiro was happy to answer.

“Yeah, I’m okay,” Yuichiro nodded and smiled. “I think… I’m more okay than I’ve been in a long time.”

Muichiro’s eyes widened, but he soon smiled back, relief clear on his face. “I’m glad… Yui, your hand!”

“Huh?” Yuichiro looked down and noticed that the incision on his left hand had partially opened up and started bleeding. When did that happen? “Ugh, Shinobu’s gonna kill me…”

That was just his luck; he survived a fight with an Upper Moon and he was still going to die because an angry midget was going to murder him. Muichiro laughed awkwardly, and Yuichiro reached into his pocket for a roll of bandages to hand to his brother.

“…So, where’d you go, anyway? And where’d that sword come from?” Yuichiro asked once he was done wrapping the wound, looking at the black blade left on the ground where Muichiro had dropped it.

Muichiro suddenly looked nervous. “Oh, um…”

A loud yelling caught Yuichiro’s attention, and Muichiro paled further. A swordsmith stormed out of the trees and made a beeline straight for the younger twin.

“You! How dare you take that sword before I finished the honing process! Do you have any idea what you could’ve done?!” He grabbed Muichiro’s kimono and started shaking him. “If you’ve damaged it, I’ll-!”

“Wait, Haganezuka!” Kanamori called as he ran to catch up. Kotetsu followed further behind, breathing heavily from the exertion on his smaller body.

“What…?” Yuichiro had no idea what was going on, but his protective instincts kicked in as he tried to separate the irate swordsmith from his twin. “Hey, let go of him!”

“Forgive us, Lord Tokito!” Kanamori bowed. “We tried to keep Haganezuka from chasing after you but he got away from us!”

“What are you talking about? Mui, what did you do?” he demanded even as he kept trying to pull them apart.

“He came into the shed and took the sword Mr. Haganezuka was sharpening for Tanjiro,” Kotetsu explained. He reached into his vest and pulled something out. “Oh, and, by the way… Tanjiro said you could have this, since he knows how much it means to you.”

Yuichiro’s eyes went wide at the sight of Kyojuro’s tsuba in Kotetsu’s hand. “Tanjiro really said that…?”

“Uh huh. Do you want it?”

“I…” Yuichiro closed his eyes, letting the surge of emotions pass over him. Anger, regret, grief, and then finally, relief. He looked back at Kotetsu and shook his head. “No, tell Tanjiro that he should keep it. He’ll use it better.”

Yuichiro didn’t need the tsuba. He felt like he could start to come to terms with Kyojuro’s death now; he had fought and died to protect innocents, and the younger slayers like Tanjiro who would go on to do great things. That tsuba was a symbol of hope for the future, one that he wanted Tanjiro to wield.

In the distance, a huge roar rang out. Muichiro burst into mist to escape Haganezuka’s grasp and reformed to snatch up the black blade. “Nii-san, Tanjiro and the others are still fighting the other Upper Moon!”

Yuichiro nodded. Exhaustion tugged at his limbs, but there was no time to rest. “Go, I’ll catch up…!”

“Oh no, you don’t-!” Haganezuka yelled, only to get tackled to the ground by Kanamori and Kotetsu, who started… tickling him? Yuichiro rolled his eyes. Whatever worked, he supposed.

Muichiro grinned. “Okay!” And then he took off, Tanjiro’s sword held in his hand. Yuichiro watched him go. He wasn’t sure he could fight in this condition, but-

No, no buts. I can fight. I am Yuichiro Tokito, the Mist Hashira! I can be as strong as I need to be to protect everyone!

Yuichiro took a deep breath and followed after his twin.

—

The sun rose, bringing a new dawn and an end to the long night. The Upper Moon Four had been felled by Tanjiro’s black blade. And Nezuko, his sister…

…Walked beneath the sunlight, alive and unharmed.

Muichiro watched from the shade of the trees as Tanjiro ran forward to embrace her, crying with relief. She smiled and hugged him back, speaking for the first time.

“Thank goodness…” Tanjiro sobbed.

“Thank goodness!” she repeated back, her voice sweet and melodious.

It was a joyous sight to behold, and yet… Muichiro felt numb. The fog pressed in all around him, making it hard to see. He couldn’t breathe, so he didn’t even try. He thought he should be happy. They’d won. Two Upper Moons were dead. Nezuko had withstood the sun, the first demon to ever do so. He should be happy.

But he didn’t feel anything.

Do you understand now?

Muichiro jumped. The shadow stood next to him, turquoise eyes staring through to his soul. He watched as it walked towards the edge of the trees.

Those principles you tried so desperately to uphold have amounted to nothing. The truth stands right here before your eyes.

It stepped out into the sun, and Muichiro’s heart caught in his throat. The shadow turned to face him, crumbling in the morning light. Its six eyes narrowed as it spoke with utmost finality.

You are still condemned.

And then it was gone, turned to ash. Muichiro could only stare at the spot where it once stood.

Tomioka was wrong. There were good demons, blessed by the gods. But Muichiro wasn’t one of them.

“Muichiro?” He turned to see Yuichiro stumble over, exhausted from the back to back battles with Upper Moon Five and then Four’s strongest form. He came to a stop beside his twin, his breaths ragged.

“Nii-san…” He didn’t say anything else. He didn’t trust himself to say anything else. Yuichiro looked past him, and he gasped at the sight of the Kamado siblings embracing under the sun. Understanding dawned in his eyes as he looked back at Muichiro, who bowed his head so he wouldn’t see his face.

“Mui… I…” He didn’t finish. They quietly watched as Genya approached the siblings, fully human again, and then Mitsuri minutes later, who pulled all three of them into a big hug.

Muichiro shook his head and looked back up, forcing himself to smile. “You should join them, Nii-san. It’s your victory, too. You deserve to celebrate it.”

Yuichiro looked at him, affronted. “It’s our victory…”

Muichiro struggled to keep his smile up. “Yeah, but, I can’t…”

Yuichiro’s eyes narrowed, a dark look on his face. Muichiro wished he would just listen and walk away. The numbness was wearing off, the fog receding, and he became aware that he was trembling. “Please, just go…”

But Yuichiro didn’t leave. Instead, he stepped closer to his twin. “I’m not going anywhere. I promised I’d always be here for you, and I will. I won’t leave you alone, especially not now.”

Muichiro felt tears come to his eyes. He lowered his head, not wanting his twin to see them fall. “…What did I do wrong?” he whispered.

A hushed gasp escaped Yuichiro before he pulled Muichiro into a sudden but gentle hug. “Nothing. You didn’t do anything wrong. This world just isn’t fair...”

Muichiro froze, surprised by the embrace, but he soon relaxed and let his brother hold him, trying to focus on his warmth and not on how cold he felt. For a moment it was just the two of them, the rest of the world an afterthought to their shared pain.

“Yuichiro! Muichiro!”

The two quickly broke apart, and Muichiro turned his head and wiped his tears before turning back. Mitsuri was smiling as she ran up, Genya practically being dragged behind her and Tanjiro and Nezuko close behind.

“We did it!” She cheered, sweeping them both up into a hug. Yuichiro growled, and she let go, smiling sheepishly. “Sorry! But… we did it! We won! We’re all alive!”

Muichiro nodded. She was right; two Upper Moons had been defeated, and no one had to die to make it happen. It was an incredible stroke of luck, or maybe it spoke to the strength of their little group.

Tanjiro approached Yuichiro with a bright smile. “Kanroji told us you protected the village and defeated an Upper Moon! That’s amazing, you two!”

Yuichiro blushed and turned away, stuttering out a quiet thanks. Muichiro felt a smile tugging at his lips before a soft voice called out to him.

“Mui…chi…ro?”

A chill ran down his spine; Muichiro turned to see Nezuko, her eyes filled with concern.

“Just Mui is fine,” he said. He didn’t want her to strain herself when she was only just starting to speak again. He forced a smile onto his face. “….Congratulations, Nezuko. I’m happy for you.”

He was glad to realize that the words slipped easily past his lips. He was happy for her, even if it felt like his heart was falling to pieces. Because Nezuko deserved to walk in the sunlight again, and he wouldn’t let his own grief take away from her joy.

Nezuko nodded. “Mui…” Then she pulled him into a hug, strong and warm as the sun. “…Thank you!”

Muichiro was caught off guard, but he soon accepted the hug, gingerly wrapping his arms around the other demon. Nezuko looked up, her eyes warm as they took in the remnants of tears on his face, and hugged him tighter. She couldn’t articulate her words well, but the meaning behind her actions was clear: don’t be sad, it will be okay.

Mitsuri squealed and joined in on the hug. Tanjiro followed next, and then surprisingly Yuichiro, who chuckled and wrapped an arm around his twin’s back. With the other, he grabbed a red-faced Genya and pulled him in. “Get over here already; this is a group hug.”

Muichiro couldn’t help but laugh. The love he felt from his brother and friends soothed the aching of his heart, mended the cracks and pushed down the rising doubt. He couldn’t step out into the light, but he wasn’t alone in the dark, either. Despite everything, he was still loved.

In that fleeting moment, he truly felt happy.

If only it could have lasted forever.

--

A/N: And the Swordsmith Village Arc comes to a close! To commemorate this chapter, I have art to share! A huge thank you to Chrysallion for this wonderfully cool art of Yuichiro and Muichiro, ready for battle! You're amazing!

Chapter Text

“Thanks for doing this for me, Aoi.”

“Don’t thank me. I’m only doing this because if I didn’t, I’d be complicit to murder.”

Yuichiro chuckled while Aoi focused on fixing his stitches and redressing his hand. He didn’t even want to think about facing Shinobu’s ire for reopening his injury, even if it was to defeat an Upper Moon. He was grateful that Aoi had agreed to take care of his checkups and wound care upon returning from the Swordsmith Village.

That didn’t mean he wouldn’t tease her, though. “Nah, you like me. We’re friends, after all.”

“Who are you again? The Yuichiro I know would never admit to being friends with anyone.”

“Wow, I make an effort to be nice and this is how you treat me? I’m hurt.” Yuichiro clutched his heart with a wounded expression.

Aoi rolled her eyes. “Well, you’re still just as much of a brat as ever. Maybe you are Yuichiro.”

“Ouch…” Yuichiro fell silent as Aoi finished dressing the wound. He turned his hand and flexed his fingers, feeling a mild sting but no worse than that. “Thanks, Aoi. It feels great.”

“Again, don’t thank me. Just take it easy for a while, okay?” she sighed.

“I’m not sure that’ll be possible,” Yuichiro chuckled. But underneath his light tone, his words were serious. Two more Upper Moons were dead, and Muzan surely wasn’t going to take that lying down. The fact that demon sightings across Japan seemed to have just suddenly ceased over the past week was concerning. He felt like something big was coming.

“…You do seem different,” Aoi commented. “You seem… happier… than before.”

“Did I seem unhappy before?” Yuichiro tilted his head.

“I don’t know about that, but you always seemed like something was bothering you. Like you had some big weight on your shoulders, you know?” Aoi shrugged, trying to explain. “But you seem lighter now, if that makes sense.”

Yuichiro thought about her words, and decided they did make sense. The specter of his parents’ deaths had always hung over him, making him a harsher person. But that specter was gone now. He accepted that Father loved Mother enough to risk his life, and that Yuichiro himself was no different in the end. He would face the future and fight to the fullest for a life where he and Muichiro could live peacefully, and he knew his parents would be proud of him for doing so.

“…Yeah, you might be right.” Yuichiro agreed, feeling at ease for once. He never realized how much tension he kept coiled up in his body all the time. He wished he could go back to the Swordsmith Village’s hot springs, but the smiths had already packed up and left for a new, more hidden location. Understandable, but still disappointing.

“…Hey, don’t you have a meeting to go to?” Aoi changed the subject when he didn’t move for several long seconds.

Yuichiro shrugged. “Sure, but we’ve got time. The Master won’t start without us, and Muichiro is still busy.”

“Where is Muichiro, anyway?” Aoi asked.

“He’s getting his check up done. He’s got his own doctor, you know?”

“Huh?”

—

“Thank you, Muichiro. This will be enough for my research.”

Muichiro nodded, barely feeling the needle leave his skin. Tamayo smiled gratefully and held the syringe near her face. She hummed, thinking. “How curious, your blood is different now compared to the sample you gave me following your battle with the Upper Moon.”

“You can tell that just by looking at it?”

“It’s mostly a feeling, but yes. I can tell that Muzan’s influence has grown weaker.”

Muichiro nodded in understanding. She must be referring to Muzan’s blood within Upper Moon Five. As more time passed since the battle, he felt the painful presence of the foreign blood less and less as his body adapted to it. He rarely even heard the shadow’s voice anymore, to his immense relief.

Tamayo turned and held the syringe out to her assistant Yushiro, who wordlessly took it and placed it in a case. The soft click of the case locking echoed in the dark room. Muichiro looked towards the window, curtains drawn to keep out the sunlight.

“…Lady Tamayo?” The demon doctor looked back at him, and Muichiro swallowed a sudden lump in his throat. “Why is it that Nezuko can walk in the sun?”

A strange look crossed Tamayo’s face. Was it worry? Pity? “My theory is that Nezuko’s body has been evolving to withstand the sunlight ever since her transformation. I believe that is why her mental state regressed to that of a child as well, to conserve energy for her body’s development.”

Muichiro nodded. “…So, why didn’t mine do that?”

Tamayo was quiet for a moment. Then she leaned forward, placing a hand on top of Muichiro’s, and smiled kindly at the young demon. “Demons are unique creatures, Muichiro. And you and Nezuko are unique even compared to them.”

“But neither of us have eaten humans, right?”

“I don’t believe it has anything to do with that. Your body has evolved specifically to kill other demons. Your mind was regressed as well, remember? And yet you developed your first Blood Demon Art within days of your transformation, and later another one capable of eating demons. That is a feat only the strongest demons should be capable of.”

Muichiro frowned. So Nezuko’s body evolved to withstand the sun, while his evolved to become a killing machine? What did that say about him? “Why, though?”

“I’m afraid you would know the answer better than I. A demon’s growth is influenced by their will and desires,” Tamayo answered. But upon seeing Muichiro’s face fall further, she added, “However, I know you have a fierce desire to protect others. I believe that your body evolved the way it did in order to fight against demons and protect those people.”

Muichiro looked at Tamayo with wide eyes. The doctor was not a liar; he trusted her judgment. So he didn’t evolve to kill, but to protect? This strong rage he felt wasn’t born out of some darkness within him, but a desire to stop evil and save the innocent. He found himself smiling at the thought.

Behind Tamayo, Yushiro scoffed and glared daggers at Muichiro who quickly looked away. It was clear the blue-haired demon still hadn’t forgiven him for biting off his hand when they first met.

Tamayo chuckled in spite of the awkward atmosphere. “Well, in other news, you’ll be happy to know that the progress on the cure is going well. Shinobu’s expertise has been quite helpful.”

Muichiro’s eyes lit up. “Really?!”

Tamayo nodded. “Indeed. I have you and your brother, as well as Tanjiro and Nezuko, to thank for that. The blood you’ve all collected from the Demon Moons over these years has been invaluable. It may still be some time before the cure is ready to be tested, but our goal is closer than ever before.”

Muichiro felt hopeful at that, even if a small part of him was still worried. The idea of a cure to turn demons back into humans hadn’t even felt possible until recently. Would it work? What would they do if it didn’t? But Muichiro shook his head to drive away those thoughts. There was no point in worrying about that now, and he trusted that Tamayo and Shinobu would succeed. “I’m sure you can do it, Lady Tamayo!”

“Thank you, Muichiro,” Tamayo said warmly. But her expression soon hardened. “However, there is something I must ask you.”

Muichiro raised an eyebrow and waited. “You are aware of Kibutsuji’s connection to his demons, yes? It is likely that when Kibutsuji dies, the demons he created will die with him. Do you still intend to fight, knowing that?”

“I do.” Muichiro answered without any hesitation. “Nii-san and I spoke with the Master about it. He’s worried, but I won’t sit this battle out. I need to be there to protect him and everyone else.”

“I see,” Tamayo nodded, accepting his decision. “When the cure is ready, you must take it before Kibutsuji dies. I will give both you and your brother a dose to take with you. Keep it safe at all costs.”

“I will. Thank you, Lady Tamayo.”

“I’m happy to help,” Tamayo smiled. “Oh, but I shouldn’t keep you much longer. You have a meeting to attend, do you not?”

Muichiro’s eyes widened; he’d almost forgotten about the Hashira meeting today! “That’s right, I have to find Nii-san! Bye, Lady Tamayo! Bye, Yushiro! I’ll see you around!”

Tamayo waved him off as he raced out the door. He didn’t see Yushiro’s reaction, but he imagined it involved eye-rolling and a gripe that they weren’t friends; he was just grumpy like that.

As Muichiro ran down the empty hallway, it didn’t take him long to spot Yuichiro heading his way.

“Oh, there you are. What- hey!” Yuichiro shouted as a cloud of mist rushed past him and into the basket on his back.

“Come on, we’re gonna be late!” Muichiro said frantically upon reforming inside.

“We’re not going to be late! They won’t start without us!” He could practically hear Yuichiro rolling his eyes. Nonetheless, he quickly left the Butterfly Estate and made haste towards the Demon Slayer Headquarters. They had much to discuss, after all.

—

The twins arrived at the Headquarters within the hour, rushing down the halls towards the meeting room. Muichiro had been sure they’d be late, but upon opening the sliding doors, the Master was still absent. He breathed a sigh of relief at that.

The rest of the Hashira were already present, so the twins took the two empty spots next to each other, furthest from the Master’s spot and across from Obanai and Shinobu. It seemed that Mitsuri had been regaling the others with the tale of their battle at the Swordsmith Village while they waited.

“Aagh, I envy you guys,” Sanemi grumbled. “Why can’t I run into Upper Moons?”

“Really now? You’re jealous of us? That’s a first,” Yuichiro snarked. The Wind Hashira rolled his eyes.

“Can it, brat. From what I heard, you almost drowned with barely a fight.”

“Yeah, but I didn’t. And then Muichiro and I not only beat Upper Moon Five, but we helped hold off Upper Moon Four until sunrise.” Yuichiro crossed his arms, smirking. “Meanwhile, what have you done? Killed some low rank demons that anyone could handle?”

Muichiro wasn’t sure if he should laugh or worry for his brother’s health if he continued on. Sanemi growled, looking furious, but then Obanai intervened. “That’s enough, we’re not here for petty arguing. More importantly, are you two alright?”

Yuichiro nodded, relaxing his arms and settling into his seat. Muichiro also nodded, his eyes glowing bright as Kaburamaru stretched out towards him. He was still too far to pet, but then Muichiro got an idea. He drew a claw across his collarbone, and the red mist bubbled up into a snake that coiled around his neck. Kaburamaru drew back, looking somewhat perturbed, before slinking forward to study the mist snake that floated still in front of him.

Shinobu ignored them as she spoke up next. “Yes, how have you been, Yuichiro? I can’t help but notice you’ve been going to Aoi for your check ups instead of me this past week. May I ask why?”

Yuichiro froze, his face suddenly turning pale. Luckily for him, it was at that moment that the door slid open. Muichiro’s mist snake dissipated as his and everyone else’s attention turned towards the door.

“My apologies, I hope you weren’t all waiting too long,” Amane said. She sat down in her husband’s usual spot with her two daughters behind her, and Muichiro felt concern. Did something happen to the Master?

“For our meeting today, I will be attending in place of Master Kagaya,” Amane explained. Her tone and face were even, but her eyes were dark with worry. “Right now, the disease affecting him has gotten worse, and he sends his apologies for being unable to attend this meeting in front of you all.”

“Understood,” Gyomei spoke up first and bowed, the rest of the Hashira following suit. “I will pray for the Master’s flickering flame of life to last a bit longer, even for just a day. And for you to stay strong, Lady Amane.”

Muichiro felt a lump forming in his throat. He knew the Master’s illness was getting worse, but to such an extent that he couldn’t even be present? It brought back memories of his mother, confined to her futon as her sickness took its toll and ultimately her life. Was the Master going to suffer that same fate?

Amane was silent for a moment, then nodded her head. “He would like to give his thanks to all the Hashira.”

And with that, they went into the meeting proper, emotions pushed aside to focus on the matter at hand. Muichiro swallowed the heavy lump in his throat and tried to pay attention.

“I’m sure you all have heard this, but we now have a demon who has conquered the sun. This demon, Nezuko Kamado, is here right now. Muzan Kibutsuji has likely altered his plans to go after her so he can conquer the sun himself. The time for an all-out battle is approaching.”

Muichiro’s eyes widened. He hadn’t thought about how Nezuko might be targeted by Muzan specifically now, but it made too much sense. And if the immortality Muzan sought was at stake, the Demon King wouldn’t be taking any chances. An all-out, final battle between the demons and the slayers would certainly be upon them.

Would Teacher be there? Of course he would; he was the Upper Moon One himself. There was no doubt that he would show himself at this battle. Muichiro wasn’t sure how he felt about that; he could never direct his hatred of demons towards the one who turned him, no matter how much he wished he could. But he might still have to fight him, maybe even deliver the finishing blow. Still, Muichiro knew where his priorities laid. He didn’t hate the Upper Moon, but if Kokushibo threatened his brother or his friends, then he would fight, no question.

“Furthermore, we have reports of strange marks appearing on Mitsuri and Yuichiro during their battles against Upper Moons Four and Five,” Amane continued, catching Muichiro’s attention again.

Both Yuichiro and Mitsuri looked up, sitting straighter as all eyes turned to them. Muichiro thought back to the red cloud-shaped mark that had appeared on Yuichiro’s face upon returning to his aid against Gyokko. It strongly resembled his own demon crest.

“During the Sengoku Era,” Amane explained, “There were some swordsmen of the First Breath who were one step away from ending Muzan Kibutsuji. They all had marks that resembled demon crests.”

The Hashira were surprised to hear that. These marks were that old? But then why hadn’t they heard anything about them until now?

Amane had an answer to that. She went on to explain how much of what was known about the marks during the Sengoku Era was lost to time. The one thing they did know, however, was that once one person acquired the mark, it would then begin to spread to the people around them, as if resonating with each other. And the first person to obtain the mark was none other than Tanjiro Kamado.

“Unfortunately, when we asked him about it, Tanjiro had a hard time explaining how he received the mark. So if you can, would you two please tell us about the mark and how you obtained it?” Amane asked.

“Yes, of course!” Mitsuri spoke up first, excited to help, but the explanation that followed was… unenlightening, to say the least. One confusing string of onomatopoeias later, the poor girl was blushing with embarrassment. Yuichiro sighed in resignation.

“Fine, I’ll explain it. I didn’t even realize there was a mark myself at the time, but based on when it happened, I think I have an idea as to how.”

All eyes turned to him. “I had to protect the village and make it back in time to help Muichiro against the Upper Moon Five. I was desperate and determined, and I remember that my heart was beating faster and faster as my emotions became stronger than ever. I think my heart was beating over two hundred beats per minute, and my body felt like it was on fire. I had a fever of over thirty-nine degrees when I was recovering, and I’m sure my body was the same temperature during the fight as well.”

Muichiro gasped; such conditions would be lethal to the human body, especially if sustained for so long. Shinobu had the same thought. “But can you move in that condition? That would have been life-threatening.”

“Normally it would. But I think that’s the difference between those who get the mark and those who don’t,” Yuichiro answered. “If you can survive, then the mark will appear.”

Muichiro stared at him with awe. A newfound surge of admiration welled up inside him for his twin who was able to survive and gain such incredible power. His brother really was amazing…!

The discussion continued from there, turning to the topic of unlocking the mark’s power for the rest of the Hashira, and maybe even the other members of the Demon Slayer Corps as well. Thus it was decided that a new training regimen for the whole of the Corps would be implemented. Each Hashira would be responsible for teaching a certain aspect of battle to the slayers who came to their estates. Yuichiro and Muichiro were put in charge of the quick movement training, focused on increasing speed and reflexes to better the slayers’ odds of surviving the battle ahead.

Yuichiro looked less than pleased at the prospect of having to teach the lower-ranked slayers anything, but as one of two Hashira with the mark, he couldn’t refuse. Muichiro smiled sympathetically; he knew Yuichiro wasn’t a good teacher, which meant the responsibility of actually training them would likely fall to him. He just hoped no one would make a fuss about learning from a demon, lest they incur his big brother’s wrath.

Once all the details and scheduling of the training were ironed out, the meeting came to a close. As the Hashira were all moving to leave, Amane spoke up, “Mitsuri, Yuichiro, would you two stay here for a minute? There’s a matter I must speak to you about.”

Yuichiro paused mid-standing up, then returned to his seat, looking at Amane with confusion. Mitsuri seemed similarly puzzled, and the departing Hashira gave them strange looks as they left the room.

But next to Yuichiro, Muichiro remained rooted in his spot, torn between obeying orders and wanting to stay with his brother. It wasn’t that he didn’t trust Amane, but he suddenly felt a sense of foreboding over what she might want to discuss with them alone.

“Hey, Mui,” Yuichiro whispered, “You have to go with the others.”

“It’s okay, Yuichiro, Muichiro can stay if he wishes to,” Amane quickly assured him. “It may be best that he hears this as well.”

Her wording did not put Muichiro at ease, but he felt grateful that she was letting him stay. The three Hashira settled into their spots and waited as the Master’s wife collected her thoughts. “First of all, what I am about to tell you should stay between us for now. Rest assured that I will inform the other Hashira as well, but as you two have already acquired the mark, I am telling you first.”

The more she spoke, the more unease Muichiro felt. But he stayed silent, waiting for her to finish.

“There is something else we know about those demon slayers who possessed the mark in the past. The mark grants immense power to its user, but such power does not come without consequence.” Amane paused, her gaze turning ever so slightly towards the twins, looking regretful, before she continued on. “There is… a curse placed upon it. None of the slayers who acquired the mark have ever lived past the age of twenty-five.”

Her revelation was met with silence. No one could even speak. The room suddenly felt cold, too cold. Like all light and warmth had departed, leaving only an icy stillness behind. Muichiro’s breathing stopped, but his heartbeat hammered in his ears, deafeningly loud.

“…What?” Yuichiro broke the deathly silence first, disbelief clear in his voice. “That… can’t be true, can it? Curses don’t…”

But Amane’s expression remained grim. “Our records show that without fail, all those who obtained the mark died before or on the day they turned twenty-five. Those who lived to be twenty-five died of unknown causes, their life simply fading away.”

Died. The word echoed in Muichiro’s head like a funeral bell.

Yuichiro had the mark, which meant...

...Yuichiro was going to die.

He was fourteen. In eleven years, his twin, his other half… was going to…

The fog closed in. The people around him were talking, but their words were muffled, separated by a thick veil. He didn’t feel anything, but something screamed beneath the sea of mist pulling him under, down into the depths of his mind. Sinking. Drowning.

He couldn’t breathe.

Muichiro stood up, the indecipherable voices around him ceasing.

“…ichiro?” Even his big brother’s voice sounded far away.

Muichiro didn’t look at him. He stared straight ahead, seeing nothing but the fog, only knowing that he couldn’t stay here. His own voice was lost in the haze.

“We… We should go.”

—

“Wait, Muichiro!”

Breaking out of his shocked stupor, Yuichiro jumped up and rushed after his brother, sparing neither Amane nor Mitsuri a second glance. He shoved aside the half-open sliding door and spotted Muichiro walking at a quick, mechanical pace down the hallway.

“Muichiro!” he called again as he ran to catch up with his twin. But Muichiro didn’t even acknowledge him. “Where are you going? It’s still daytime; you can’t go anywhere!”

That got Muichiro to pause, the demon going still as a statue. Then without saying a word, he started walking again, slower, and turned a corner to a different hallway. Yuichiro groaned and followed after.

He knew why Muichiro was acting strange; he’d just found out that his big brother was going to die in only eleven years. Less than that, even, as their fifteenth birthday was only a few months away now. Strangely, the knowledge didn’t cause Yuichiro as much distress as he thought it should have; maybe a part of him was still in denial. But Muichiro was clearly upset, and that was what bothered him the most right now.

After a few minutes, Yuichiro finally realized where his twin was going. They turned one more corner, and their old room stood to the left. Muichiro shoved open the door and walked inside, and Yuichiro followed, closing it more gently behind him.

The room was dark and relatively untouched, not that they ever had much to fill it with in the first place. Muichiro stopped and knelt down next to the table left in the center of the room. His head was bowed and he still wouldn’t say anything. Yuichiro felt on edge, scared to speak and break the tense silence, but he needed to say something.

“You’re going to die.”

Except Muichiro beat him to it, and for some reason, that was such a surprise that what his twin actually said didn’t register in his mind. “What?”

Muichiro’s body shook. Then almost faster than Yuichiro could follow, his claws dug deep into the table. The wood cracked, and with a scream the table was thrown at the wall, shattering on impact. Yuichiro jumped; sometimes he forgot how strong Muichiro actually was.

But Muichiro’s anger left him as quickly as it came. He slumped forward, breathing heavily. “I… I’m sorry...”

Brotherly instincts kicked in, and Yuichiro moved forward to kneel by his side. “Don’t apologize. It’s okay.”

“No, it’s not! Nothing is okay!” Muichiro shook his head frantically. “The mark… You’re going to die!”

Yuichiro flinched. “Muichiro, I…”

He couldn’t finish, couldn’t find any words to respond with. Muichiro’s eyes were wide and full of distress. “You what? What were you going to say? That you won’t? It’s a curse; you can’t avoid it. You can’t stop it.”

“That’s… that’s not true. Curses can be broken.” Admittedly, Yuichiro had never believed in curses before, or the old stories about breaking them. But then again, he hadn’t believed that demons existed for most of his life either. “We’ll find a way to beat it.”

“And what if we can’t? What then? In eleven years, you’ll be gone. Dead by the age of twenty-five… that’s…!”

Yuichiro felt a pang in his heart. “Listen, Muichiro, we’re Hashira, remember? We always accepted that we might not live long lives.”

The irony of his words was not lost on him, and Muichiro realized that too. “I know that! But this… this is different! This isn’t some maybe; this is going to happen! I can't protect you from this! If you die, I'll..." He shook his head, abandoning whatever he was going to say. "...I can’t lose you...!”

Yuichiro struggled to find his words. What could he say? He knew if their situations were reversed, he’d feel the exact same way. He tried desperately to think of anything that might be a comfort to his brother. “H-Hey, don’t talk like that. You have more than just me, you know? Even if I’m gone, you have so many other friends who will support you.”

But that seemed to be the wrong thing to say. Muichiro went quiet, his eyes narrowing. “...Other friends, huh?” A note of bitterness crept into his shaking voice. “You mean like Tanjiro? Or Mitsuri?”

“Um… Yeah? Who else would I-” And then it hit him, what Muichiro was really saying. Tanjiro and Mitsuri both had the mark. They would die by the age of twenty-five as well, and because they were older, they would both be gone before Yuichiro passed.

The reality of the curse started to set in at that moment. His life, and the lives of everyone else with the mark, were on a timer. Any goals or dreams they might have had for a future without demons would be cut short. Tanjiro would leave his sister behind. Mitsuri, who wanted to find love and have a family, only had six more years left to live. And Yuichiro, who had found his resolve in staying by Muichiro’s side, would eventually break his promise. It was… so unfair.

Muichiro squeezed his eyes shut, fighting back tears. “I know… I know it’s unrealistic to think we’ll all make it through this final battle alive. But I… I wanted to hope that…”

Yuichiro nodded; he understood. In his plans for the future, he used to only ever consider himself and his brother. But over time, other people had wormed their way into his heart. The Master and his family, the other Hashira, Tanjiro and Nezuko; despite all his efforts to not grow attached, he found himself hoping they could all live their lives together in a world without demons. Yuichiro knew those thoughts were nothing but fleeting fantasies; there was no guarantee any of them would survive to see that world. To hope for something so improbable was naive and foolish.

But no matter how improbable, having a fantasy crushed right before your eyes was a painful thing.

Tears started to fall as Muichiro choked back a sob. “Aren’t you upset?! This is your life!”

Yuichiro winced; he was trying to stay calm for Muichiro’s sake, but maybe that wasn’t what his twin wanted right now. But even if he was shocked to learn of the mark’s curse, he wasn’t that upset by it. Or rather, he wasn’t upset for his own sake. He had resolved long ago to give his life for Muichiro if need be, and this was simply an extension of that. Even if he had a choice, he would still choose to cut his life short in exchange for the power to make sure his twin could live peacefully as a human.

But saying that wouldn’t help Muichiro. What he needed was assurance that everything would be okay.

Quietly, Yuichiro slid off his haori and placed it over Muichiro’s shoulders. The younger twin froze, claws raising to grip the fabric and relaxing immediately upon realizing what it was.

“What are you doing?” he asked.

“I’m making you a promise,” Yuichiro answered. “Another one, I mean. As long as you have this haori, I’ll be with you. Even when we’re apart, you’ll always have a part of me to hold onto.”

“But… this is your’s.”

“Right, and you’ll give it back once we’ve found a way to break this curse.”

“What?”

“When we defeat Muzan and make a world without demons, you and I are going to find a way to break the mark’s curse.” Yuichiro repeated. If there was one thing about the mark that he did resent, it was the pain it was causing his twin. “I’m not going to just accept this, you know? I won’t just give up and die. So I don’t want you to give up either, okay?”

Muichiro sniffed and wrapped the haori around himself. He shook, and then he leapt at Yuichiro, wrapping him in a tight hug. “You can’t… You can’t leave me! Not after everything we’ve gone through…!”

His desperate strength was painful, but Yuichiro didn’t make a sound. “I… I won’t. I’ll stay with you. I promise…”

But despite all his brave words, Yuichiro was scared, too. Because he didn’t know if he would be able to keep his promise. No one could say for sure how this final battle would end. Life or death, victory or defeat; he didn’t know.

All he could do was hold Muichiro and hold tight to his vow. He would do everything in his power to stay with him.

And may Heaven help whoever got in his way.

—

“Kokushibo.”

The Upper Moon One looked up at his lord’s call, rising from his bowed position. Muzan Kibutsuji stood on a platform high above, looking down upon his strongest subordinate.

“Those children you so favor have defeated Gyokko. It appears you were right to believe that they would grow stronger on their own.”

Kokushibo nodded. He was well aware, having seen glimpses of the battle through his and Muichiro’s connection. He felt pride, but also… concern, having come to the same realization that his student’s power had come into its own.

Muzan’s cold gaze showed his displeasure. “But I've waited long enough. It’s time to reap the rewards of our investment.”

Kokushibo kept his expression neutral. This was what he wanted, was it not? A student whom he could pass on his teachings to. A descendant who would follow in his footsteps and continue his legacy. And yet he hesitated, feeling unease. But he could not refuse an order from his king.

“As you wish, my Lord.”

The Demon King’s red eyes bored into his very soul.

“You know what to do. Do not fail me, Kokushibo.”

Chapter Text

Despite everything, life continued on.

The day for the Hashira training to begin soon arrived. Yuichiro woke up early, planning to make sure the Mist Estate was clean and well prepared to receive its new guests. He looked over to Muichiro, asleep next to him in their shared futon. Or at least, he assumed he was asleep. They were getting too old to sleep together like this, but Muichiro had requested it, and Yuichiro could never deny him.

Slowly, carefully, he inched his way out from the futon, trying his hardest not to wake his twin. After a few minutes, he crawled away and moved towards the door. He hoped to let Muichiro get some sleep, and maybe get some time to himself. His twin had been awfully clingy as of late, not that Yuichiro blamed him for it. He was about to slide the door open when a soft voice called out to him.

“Yui?”

Yuichiro let out a sigh and turned back to Muichiro with a small smile. “Good morning, Mui. Did I wake you?”

Muichiro shook his head. “I didn’t sleep.”

“You know you shouldn’t do that.”

“It’s fine, I don’t get tired, remember? And besides, when I sleep, I…” he trailed off, but Yuichiro could guess what he was going to say. The older twin sighed again; as much as it wasn’t good for Muichiro to skip sleeping, he didn’t have the heart to lecture him right now.

“Well, since you’re awake, you can help me get everything ready. The low-ranks will be here soon.”

“You shouldn’t call them that, Yui,” Muichiro chuckled as he got up and followed his brother out of the room.

“What else am I supposed to call them?”

“I don’t know, just trainees, maybe? It sounds nicer.”

Yuichiro grunted noncommittally; he really didn’t care about being nicer to the average rank slayers of the Corps. The idea that he had to be patient with people who constantly pissed him off and whispered behind his and his twin’s backs was unappealing, to say the least.

But then again, it wasn’t all bad. At least he had an excuse to knock them around a bit during training.

Preparing the Estate to meet the trainees didn’t take much time at all, and soon the doors were opened to allow them inside. The twins couldn’t alter the slayers’ schedules to train at night, so all their training would have to be done inside during the day. A group of about fifteen slayers trickled in; Yuichiro had been expecting more, but then he remembered that the trainees needed to pass Uzui’s stamina training and Mitsuri’s flexibility training before they could even come here. And as the days went on, more slayers would surely arrive, so he supposed he should be grateful for the relatively small crowd today.

Muichiro kept his demonic features hidden as he welcomed the trainees inside, pretending not to notice the wary looks still thrown his way. But Yuichiro had no reservations about making his displeasure known, his caustic glare succeeding in making them stop. He smirked as the trainees quickly fell into line, a not small part of him taking pleasure in watching them squirm.

Serves them right.

The two Mist Hashira led their new students to the training arena, where they turned to formally address the crowd of slayers. Yuichiro suddenly felt a little nervous about speaking in front of a bunch of strangers, but he soon covered it up with his usual harsh exterior.

“Alright, listen up. My name is Yuichiro Tokito, and this is my brother, Muichiro Tokito. Yes, he’s a demon. But we’re both the Mist Hashira, got that?” The other slayers nodded nervously. “Good. Now, today you’ll be starting quick movement training. The Upper Moons can move as fast as you can blink, some even faster than that, and so your speed and reflexes will need to be at their peak if you want even a chance at surviving.”

He paused, and Muichiro spoke up next. “At least one of the Upper Moons fights with a sword, but most demons don’t, and will prefer attacking at close range with their claws and fangs. So to start our training off, we’ll have each of you try to attack me one-on-one to establish a baseline for your abilities. I’ll be using only my claws to block your strikes. Any questions?”

There was a long silence as the trainees looked hesitantly amongst each other. It was clear that a question was hanging in the air, so Muichiro waited patiently for someone to voice it. Finally, one boy found the courage to speak up. “Um… Tokito-Sensei? Aren’t we going to use wooden swords for this?”

“We will, once our initial testing is over. But we want you to fight as if you’re in a true battle, and you won’t do that if you’re wielding wooden training swords.”

“But…” the boy still looked nervous. “What if we cut your neck by accident?”

Yuichiro suddenly snorted, cutting off Muichiro’s response. “Nii-san?”

A laugh bubbled up in Yuichiro’s throat, keeping him from answering. But he couldn’t help it. He wasn’t sure why, but the honest confusion and worry in the trainee’s voice was just hilarious! The more he thought about it, the funnier it got!

By accident? Did he actually think he could even hit Muichiro if he tried, let alone by accident?! The same demon who was on the level of a Hashira, who battled against two Upper Moons and put them both on the ropes, and these low-rank nobodies thought they could pose any threat to him at all? What a joke!

His laughter escaped him, turning into a full-blown cackle. He probably sounded like a demon himself. Muichiro seemed to pick up on the source of his amusement, chuckling lightly. Then to the surprise of all but his brother, he joined in. He faced the increasingly frightened trainees with a wide grin revealing his fangs, six eyes opening with a bright glow and his hair floating behind him, the very image of a fearsome demon. Side by side, they struck true fear into the hearts of their students.

“Tell you what!” Yuichiro cut off his laughter, grinning maniacally. “If any of you can even touch Muichiro, then you pass and can move straight on to the next Hashira! So go on, give it your best shot! Who’s up first?!”

It was on that day that the unfortunate slayers realized that the stories of the “Twin Demons” whispered throughout the Corps were more real than any of them could have imagined.

—

"Do you think we went overboard, Yui?"

"Nah, a little fear is good; it shows who's in charge. Besides, it'll make the enemy seem less scary in comparison."

Muichiro laughed. Not a single person had managed to lay so much as a scratch on him the entire day. It was nighttime now, and the lower-rank slayers were allowed to retire for dinner. The twins finally had some time to themselves; they sat on the engawa, far away from the trainees occupying their estate, Yuichiro eating while Muichiro stared up at the stars.

Muichiro sat close to his brother, taking comfort in his presence. He knew he was being clingy, but feeling Yuichiro’s warmth and hearing his breathing and heartbeat reassured some irrational part of him that he was still there. It reminded him of the days of their childhood, when he’d hold on to his big brother’s hand as they explored the forest or crawl into his futon after a nightmare. Those were better days, when they were just kids with nothing to worry about.

Their quiet peace was interrupted by the sound of footsteps approaching. “Um, excuse me? I’m here for the quick movement training…?”

The twins looked up, and Muichiro brightened at the sight of Genya walking towards them. “Genya! It’s good to see you!”

“Um, you too…” Genya looked awkwardly away, but his tone was devoid of his previous harshness. Fighting together at the Swordsmith Village had done wonders for their budding friendship.

“Well to answer your question, yes, we’re handling the quick movement training,” Yuichiro explained. “But training’s over for today, so you’ll start with the others tomorrow.”

Genya nodded. “Alright.”

Yuichiro nodded back. “You’re here earlier than I expected, though. I thought you’d still be in recovery with Tanjiro.”

Muichiro had the same thought. He’d heard that Genya couldn’t even use breaths, so he expected him to take longer to recover and to get through the required training with Uzui and Mitsuri. But maybe his ability to eat demons and take on their power had something to do with it?

“I heal faster than most people,” Genya explained simply, not elaborating. Maybe he thought Yuichiro didn’t know he ate demons, and didn’t want him to know. Even though Muichiro did the same thing.

Yuichiro picked up on his evasiveness as well. “Hey, Genya, you said Shinazugawa was your brother, right? Does he know about you eating demons?”

Muichiro wondered about that; he couldn’t imagine Sanemi taking such news even remotely well. And indeed, Genya looked petrified by the thought, his face going pale. Yuichiro frowned. “I’m guessing that’s a no.”

“You don’t have to worry about that here, though!” Muichiro was quick to assure him. “I eat demons too, remember?”

In fact, he was quite happy to meet someone else who ate demons. Though Genya was a strange case all on his own, it made Muichiro feel a little less like an anomaly to see they shared a similar diet.

“Yeah, we aren’t judging,” Yuichiro agreed. “But I do want to know how you even found out you could do that. What made you try eating a demon in the first place?”

“I don’t know! It just… happened,” Genya looked both angry and embarrassed, his face turning an amusing shade of red. “I was in a fight with a demon and lost my sword, so I got desperate and just… took a bite out of him.”

“And Shinazugawa doesn’t know about this, right?”

“No, he doesn’t. Aniki doesn’t even want me in the Demon Slayer Corps, so he wouldn’t take it well.”

“So why are you here if he doesn’t want you to be?” Yuichiro asked. “This job isn’t for just anybody. If you want to stay close to him, why not become a Kakushi, or work at the Butterfly Estate? With how reckless Shinazugawa is, you’d see him plenty if you did that.”

“I know, but… that isn’t an option for me.” Genya’s anger faded away, and he just looked sad now. “Aniki won’t even look at me right now. The only way he’ll acknowledge me is if I’m on the same level as him: a Hashira.”

“That’s not possible,” Yuichiro said bluntly. “If you can’t even use breaths, you won’t ever get on the level of a Hashira.”

“Nii-san-” Muichiro started, about to scold him for his harshness.

“No, it’s okay. He’s right.” Genya interrupted. “I know I probably can’t become a Hashira. But still, I need to talk to him. I need to apologize for the things I said to him.”

Muichiro tilted his head, wondering what could have happened to create such a divide between the two brothers. But he felt bad for Genya; he seemed to be earnestly trying to make amends, yet Sanemi never spoke about him or even acknowledged him as his brother. He looked over at Yuichiro and noticed the familiar protective anger on his face. Muichiro knew how much he and Sanemi failed to get along, and there was a chance Yuichiro would march right over the Wind Estate to give the Hashira a piece of his mind.

Which meant it was up to him to be the rational one here.

“I think you should just try talking to him, Genya,” Muichiro suggested. “We’ll help you if you want, but if you really want things to change, you two have to talk to each other.”

“And if Shinazugawa doesn’t want to talk, we’ll tie him down until he does,” Yuichiro added with a smirk.

“Nii-san!” Muichiro gasped, though his smile betrayed his amusement at the mental image his words created.

“What? I’m joking!” Yuichiro laughed. “…Mostly. I’ll totally do it if you want me to, though.”

Muichiro just laughed and nodded his agreement. It was a bad idea, but he could get behind it.

“Um… I’ll get back to you on that,” Genya said awkwardly, but their antics seemed to have succeeded in lifting his mood. A small smile crossed his face. “But, thank you for offering. I’ll try talking to him again.”

“Good luck with that,” Yuichiro smirked. “Anyway, you can go join the others inside for dinner if you want. Better hurry before all the food’s gone, though.”

Genya nodded and walked past the twins to go inside. As soon as he was gone, Muichiro’s lighthearted mood slipped away. Genya and Sanemi’s situation saddened him; it reminded him of how he and Yuichiro used to be. “I hope Genya and Shinazugawa can make up soon.”

They would have to, because they had so little time left. The final battle was approaching, and beyond that, Sanemi, who was already twenty-one, was training to acquire the mark. And if he did…

“Me too,” Yuichiro agreed. Then his eyes turned to his little brother, and he looked concerned. “What’s on your mind?”

“It’s just…” Muichiro swallows and voiced his thoughts. “Even if they make up, Shinazugawa is training to get the mark. So even if they survive, they won’t have much time together.”

Someone like Genya, who couldn’t use breaths and relied on the power of demons, wouldn’t be able to attain the mark. Most likely, he would long outlive his older brother. Just like Muichiro would.

“…Sorry, forget I said anything. This isn’t the time to be thinking about that,” Muichiro said with a frustrated scowl.

“No, that’s not true,” Yuichiro sat up straighter and turned to face his twin, who looked back with surprise. “It’s not bad to think about the future. You just can’t let it get in the way of what’s going on now.”

“Yeah, I know. Sorry…”

“Don’t apologize; you’ve got nothing to be sorry for,” Yuichiro shook his head. “Look, life is unpredictable. Shinazugawa could survive the battle against Muzan, and then a week later he could die from tripping and slamming his head on a rock.”

Muichiro let out a snort, trying not to laugh at the thought. “Do you really think that could happen?”

“Probably not; Shinazugawa’s too hard-headed for that to kill him,” Yuichiro grinned smugly; it was a good thing Genya wasn’t around to hear him. “But you know what I mean. What could happen in the future isn’t a reason to not do things now. And for those two, it’s even more important that they make up soon, so they can have as much time together as possible.”

“You mean like how we did?” Muichiro asked.

“Yeah, exactly! They could learn a thing or two from us, don’t you think?”

“I wonder…”

“Hey, what are you trying to say?!”

“Nothing,” Muichiro chuckled. “Just that I’m glad to have a brother like you.”

He sounded so sappy, but he meant every word. And Yuichiro smiled back, unbothered by his sentimentality. “Yeah? Well, that goes for both of us. If there’s one thing I can thank the gods for, it’s that they gave me a brother like you.”

He reached out and placed his hand on top of Muichiro’s hand, gently wrapping their fingers together. “It’s going to be okay. The important thing is now. And whatever happens next, we’ll face it together.”

Muichiro tried to put on a brave face. Yuichiro was right. Whatever the future held, what mattered now was getting stronger and keeping Yuichiro safe. He closed his eyes and leaned his head against his twin’s shoulder.

“…Yeah, together.”

—

Another week passed since the Hashira training began. Both twins led the quick movement training each day, the low rank slayers slowly becoming more competent day by day. They also took part in the mark training, sparring with the other Hashira to keep their own skills sharp. It kept them busy, but as was his habit, Yuichiro still found time to keep a careful watch on his brother’s wellbeing.

When he was around other people, Muichiro was his usual self, cheerful, motivated, and encouraging of others. And yet, there were still times when a dark cloud hung over him, a somberness that was allowed to show only when he thought no one was looking. But Yuichiro noticed. He did his best to help, but everyone was feeling the pressure of the approaching battle. He wished he could find a way to cheer his twin up.

And then the answer came, one day, in the form of Tanjiro Kamado.

It was early evening when Yuichiro spotted the boy walking up the path to the Mist Estate. He’d been out training on his own while Muichiro handled the last of the day’s teaching inside, but he dropped everything to greet him on the way in.

“Tanjiro, you’re here!” He called, stopping in front of the older boy.

“Yeah, Kanroji said that I could move onto the quick movement training today,” Tanjiro answered. “That’s you two, right?”

Yuichiro nodded, smiling. “That’s right. We’re glad to have you.”

“Glad to be here!” Tanjiro smiled back. “Is Muichiro around?”

“He’s inside with the other trainees. We’re finishing up for the day, though, so you might as well relax and wait for tomorrow’s session,” Yuichiro explained.

“Oh, okay. I’m sorry for showing up so late!”

Yuichiro shook his head. “Don’t worry about it. Anyway, how’s Nezuko? Is she not with you?”

“Sorry, she’s not. Since Muzan will be trying to find her, the Master decided it was better that she stay somewhere hidden for now,” Tanjiro said, frowning.

“That’s a shame,” Yuichiro had thought that maybe seeing Nezuko again would cheer Muichiro up, but it couldn’t be helped. “Well, since we’ve got some time before dinner, how about a spar? I’ll be able to see how far along your skills are this way.”

“Oh, sure! I’d be happy to!” Tanjiro nodded enthusiastically and let the Mist Hashira lead him over to where he’d been training. As they clashed wooden blades, Yuichiro held back to gauge Tanjiro’s speed and reflexes, and was pleased to find that he was well above the other trainees in both aspects. He could easily see him becoming a Hashira, though he hoped that there would be no need for such titles soon enough.

After a few minutes, they stepped back for a break, and Yuichiro asked a question that had been on the back of his mind. “Hey, Tanjiro?”

“Hm?”

“Does Nezuko know about the mark’s curse?”

Tanjiro’s face fell, and he looked troubled. “Yeah, she does.”

“And how does she feel about it?” Yuichiro pressed.

“She’s not happy, but… she understands,” Tanjiro tried to smile, even if it didn’t quite reach his eyes. “But I don’t regret it, you know? If this power will help me make Nezuko human and rid the world of demons, then it’s worth it.”

Yuichiro nodded; he understood that. But still, he scowled. “You’re not just going to accept that, are you?”

Tanjiro blinked, confused. “What do you mean?”

“I promised Muichiro I’d always be there for him. I’m going to keep that promise, which means I’m not going to just lie down and die when I turn twenty-five.” Yuichiro’s grip on the bokken tightened, determination clear in his gaze. “When this is all over, Muichiro and I are leaving to find a way to break the mark’s curse. And… I’d like for you to come with us.”

“Huh? Me?” Tanjiro’s eyes went wide.

“Well, you and Nezuko, I mean,” Yuichiro added quickly. He didn’t want Tanjiro to misunderstand his invitation. “I understand if you don’t want to, but… we’d appreciate your help, that’s all.”

He felt stupid for asking as soon as the request was out of his mouth, but Tanjiro just looked surprised.

“Yuichiro…” Then his surprise faded, and he smiled earnestly. “You’re right, we can’t just give up! I’d be honored to go with you to find a cure!”

Yuichiro couldn’t hide his surprise; he’d fully expected Tanjiro to reject his invitation. He would have every right to want to settle down and live life with his sister and friends after this was over, and yet here he was, agreeing to come on this journey with him and Muichiro. A journey that might not even yield anything in the end, if he was being realistic. And yet, his heart felt light. He smiled back. “Thank you, Tanjiro. I’m sure Muichiro will be happy, too.”

Tanjiro nodded, looking pleased. “How is Muichiro doing, anyway?”

“He’s okay, but… he’s feeling a little down, with all that’s been happening. And especially after hearing about the curse,” Yuichiro admitted. “But, I think it’ll really help him to know that you’ll come with us after we’ve defeated Muzan.”

Yuichiro was aware that he was making a lot of assumptions. They might not defeat Muzan, and even if they did, they might not all make it out alive to go on this journey. But he had to hope that they would.

Tanjiro frowned, concerned. “I hope you’re right. I’m not sure what I can do, but I’d be happy to help in any way I can.”

Yuichiro hummed in thought; even Tanjiro didn’t have the answers to all his problems. But his gaze idly swept over Tanjiro’s black sword at his hip, and an idea came to him.

“Actually, I think there is a way you can help Muichiro right now.”

—

“Good job, Genya! You’re really improving!”

“Ugh, somehow I find that hard to believe…” the teen in question grunted as he sat up on the floor. Muichiro held out a hand to help him up, not having any trouble lifting him despite his shorter stature.

“But you are! You were able to keep up with my attacks for fifteen seconds longer this time!” Muichiro praised him with a smile.

“You were keeping track, huh?” Genya muttered, scratching his head. “Well, whatever. Every little bit helps, right?”

Muichiro nodded in agreement. He was about to suggest they go for one more round before dinner when a familiar voice called out, “Hey, Muichiro!”

The demon turned around, and his eyes lit up at the sight of Tanjiro entering the training room with Yuichiro following just behind him. Muichiro dropped his bokken and raced over to greet the boy. “Tanjiro! Are you here for training?”

Tanjiro nodded. “Yeah, I am! Yuichiro says I’ll be starting tomorrow!”

“That’s great!” Muichiro looked past him, trying to sense if a certain other demon was around, but he couldn’t feel anything. “Is Nezuko with you?”

Tanjiro smiled apologetically. “Sorry, she’s not. But she told me to tell you she’s doing well, and that she said hi!”

Muichiro nodded, feeling disappointed but trying not to show it. He was still happy to see Tanjiro. “I see. Tell her I said hi back, then!”

“Will do!”

“Hey, Muichiro,” his big brother spoke up. “Let’s call the training here for tonight. I want you to see something.”

Muichiro raised an eyebrow, confused. But he did as he was told, and soon Yuichiro led him out to the courtyard. Tanjiro and Genya came along too, the latter mostly at the former’s insistence.

“What are we doing, Nii-san?” Muichiro finally asked once they stopped.

“Well, I was thinking, we’re all trying to get stronger before the battle with Muzan, right?” He nodded, and Yuichiro continued. “So, I thought it might help if you could learn the Hinokami Kagura from Tanjiro.”

“Huh?”

“Yuichiro told me about how quickly you learned Mist Breathing and Moon Breathing,” Tanjiro elaborated. “The Hinokami Kagura was passed down in my family after they learned it from a swordsman who used the First Breathing, Sun Breathing.”

“Sun Breathing?” So that was the name of the First Breathing.

“Yeah, you could say that the Hinokami Kagura is Sun Breathing,” Tanjiro went on. “And in that case, it’d be good if more demon slayers could learn it, right?”

Muichiro nodded. The First Breathing would naturally be the strongest of the Breathing Styles. If he could learn it, it would give them an incredible advantage against Muzan and his demons.

“I know you can do it,” Yuichiro encouraged him. “There’s no one else who can pick up sword techniques the way you do!”

“You think so…?” Muichiro felt his spirit lift at hearing his brother’s praise. He knew he had a talent for swordsmanship, even if he tried not to brag about it, and the thought of learning the First Breathing excited him. “Okay, let’s do it!”

“Great! I’m not perfect, but I’ll teach you everything I know!” Tanjiro grinned. The twins and Genya stepped back to give him some space, and he drew his black blade from its sheath. “The Hinokami Kagura is a dance to honor the Fire God. And the twelve forms of Sun Breathing are meant to flow together as this dance. If done right, you can dance through the forms forever without ever running out of stamina.”

Muichiro watched attentively. He observed Tanjiro’s breathing and movements as he went through the forms one by one. First, second, third, and so forth, all linked together in a powerful, flowing dance. He could see the fire forming along the blade, blazing with a brilliant intensity, burning…

Burning…

A strange feeling ran through Muichiro’s body. An itching, agitated feeling, somewhat like how he felt whenever he broke apart into mist. His very cells were crawling, trying to move apart, trying to get away-

His vision of Tanjiro shifted. In his place was a man with long, blazing red hair tied in a ponytail, wearing a pair of hanafuda earrings. A red mark adorned his forehead, shaped like a flame. He moved through the forms with an effortless precision, fire dancing all around him, like a god given form.

Teacher? No… Who…?

The crawling in his cells grew stronger, almost unbearably so. His vision shifted again, and the young man was older now, wrinkled and white-haired with age. But he still held that black sword with purpose, pointed towards…

…towards him.

“This is heart-wrenching, brother.”

Muichiro stumbled back. Brother? No, this wasn’t… who was this? The world fell away until it was just him and the man; an intense pounding in his chest and ears drowning out everything else. He felt a surge of emotions: disbelief, anger, fear, all so strong, too strong to be his. A primal terror, the desperation of an animal faced with certain death and no escape. He squeezed his eyes shut, hearing a distant roar, a cry for him to fight back. Kill him, it screamed, or he’ll kill you-!

“Calm down, Muichiro!”

Muichiro’s eyes snapped open. He looked into his twin’s face, teal eyes wide with alarm. The incomprehensible fear drained away, and memory flooded in. He was in the courtyard, watching Tanjiro perform the Hinokami Kagura. The man with the hanafuda earrings was gone, and Tanjiro looked at him with a worried expression that made his skin crawl. He looked down at Yuichiro’s hands holding his wrists in a death grip, his own claws cutting into his skin and bleeding.

His heart was still racing, and it only picked up as he became aware of the Devouring Mist swirling around him. It was settling down, but it still rumbled threateningly, warning against anyone but his most precious person to approach. He could feel that it had been only seconds away from striking out…

Realization sank in. His mind had been locked in a memory that wasn't his, experiencing a fear for his life that wasn’t his. But if Yuichiro hadn’t woken him up, the blood mist would have attacked the man with the earrings to defend him.

Except there was no man, only Tanjiro. It would have attacked Tanjiro. He would have attacked Tanjiro.

Muichiro looked up, seeing Genya in a defensive stance, hand half-raised towards the gun at his hip. But behind him was something that made his blood run cold. Some of the trainees were at the doors, no doubt attracted by the commotion outside. They looked at him with a mix of expressions, from confusion to fear to contempt. Some of them whispered amongst themselves.

“Did you see that…?”

“What’s that red mist? It gives me the creeps…”

“I told you, you can’t trust a demon…”

Their words rang like thunder in his ears. Muichiro stepped back, his body trembling and his breathing becoming erratic. But Yuichiro held his grip firmly, keeping him from retreating too far. “Wait, Muichiro! Whatever happened, it’s not your fault! We all know that!”

No, it was his fault. Whatever happened to him happened because he was a demon, and it could happen again. It wasn’t safe for him to be here. He wasn’t safe to be around!

Muichiro’s hands turned to mist, slipping through Yuichiro’s fingers. The flash of panic in his twin’s eyes broke his heart.

“Muichiro, don’t-!”

But he didn’t stay to listen. He ran, leaping over the estate’s walls and fleeing into the forest. He ran without any destination in mind; he just had to get away, far away from anyone he could hurt. He stopped only when he was sure he wouldn’t be followed. Breathing heavily, Muichiro collapsed against a tree, curling up and burying his face in his knees.

What was that? Were those Muzan’s memories? He knew that other demons could sometimes see the demon king’s memories through their shared cells. But then, why did the man call him brother?

It didn’t make sense. Nothing made sense; he didn’t understand a single thing about himself. Not the vision, not his body's instincts, not the fog in his mind nor the fiery rage that he always had to fight to control. He hated it; he hated being like this.

His claws gripped Yuichiro’s haori and he pulled it tighter around himself, trying to draw some comfort from his scent on the fabric. The forest was quiet, the summer air warm. Gradually, his heartbeat slowed and his mind quieted. He became able to think rationally again.

What should he do now? He knew he should go back, but how could he face everyone? Yuichiro and Tanjiro and probably Genya would forgive him, but to the other slayers, he had almost attacked Tanjiro out of nowhere. They would never trust him after this.

No, he couldn’t go back. Not yet, at least. Yuichiro would be worried, but he needed time to calm down and think. The forest was peaceful at this time of night, and no demons had been spotted in over a month now. And even if one did show up, it would quickly regret crossing him.

Maybe he could just rest here, until he was ready to face reality again.

A footstep, crushing a branch beneath it, caused Muichiro’s head to shoot up. His breath caught in his throat, his eyes widening at the sight of a figure he hadn’t seen in two years. He hadn’t changed at all; a purple kimono, wild black hair like a lion’s, and six glowing eyes.

“Teacher…” Muichiro stood up, instantly on guard. What could the Upper Moon want? To appear now, after so long, it couldn’t possibly be anything good.

But the demon’s stance remained neutral, his sword sheathed at his hip. His face was as impossible to read as ever. Another moment of silence passed before he spoke.

“You’ve grown stronger…” It was not a question, merely a simple observation. The Upper Moon turned away, three of his eyes glancing back at the younger demon. “Come… walk with me.”

Muichiro stayed where he was, not moving an inch. Kokushibo turned back slightly, his lips bent in a frown. “I do not wish to harm you… I simply desire to speak to you.”

His tone was neutral, but Muichiro knew there was no room to refuse. Retreating to the Mist Estate was no longer an option; he couldn’t risk the Upper Moon following him back. Fighting or fleeing were also unlikely to end well for him, alone as he was. All he could do was follow, and stay wary.

Silently, Muichiro stepped forward. Kokushibo nodded his approval and started walking. Muichiro wasn’t sure where they were going, but he didn’t sense any other demons but his Teacher. It was just the two of them here.

“I should apologize to you,” Kokushibo spoke suddenly as they walked, catching Muichiro off guard.

“Huh? Why?” He was sure the demon had a lot to apologize for, but what to him specifically?

“That memory you saw… was my own,” Kokushibo explained. “We are… connected by blood. There are times when I see through your eyes… and you through mine.”

A cold shock ran through Muichiro’s body. Then that memory, the hate and fear he felt facing that man, it was the Upper Moon One’s? But who could that man be, to evoke such emotions in one of the strongest demons alive?

No, more importantly, what did he mean by them being connected? Kokushibo saw what he saw; was he spying on them this whole time? The mere thought was horrifying, thinking of what he could have learned without his knowledge. And why had Muichiro never seen anything like that memory until now? “That’s never happened before…”

“It was not for you to see… but my emotions got the better of me.” Kokushibo almost sounded annoyed, the slightest edge to his tone. “I have not seen those techniques performed… in a long time. They reminded me… of him.”

Those techniques? Was he saying that memory was brought about by seeing the Sun Breathing techniques? And ‘him’ had to be that man. Now that he thought about it, the man in the memory looked very similar to Kokushibo himself. “Who was he?”

Kokushibo was silent for a long while before he finally answered. “…His name was Yoriichi Tsugikuni. He was… my younger twin brother.”

Muichiro let out a soft gasp; Kokushibo was a twin? Like him and Yuichiro? “What happened to him?”

Kokushibo didn’t answer; his only reaction was his lips tightening. Muichiro thought back on the memory. The Yoriichi in his vision had been human, an old man, but he still wielded his sword with intent. The intent to destroy the demon that his brother had become. But that demon was here, and Yoriichi wasn’t.

Did Kokushibo kill his own twin?

“What was he like?”

“He was… quiet, but kind,” Kokushibo said slowly, almost wistfully. “And he possessed… incredible talent.” Another pause, and then he continued. “You… remind me of him.”

Muichiro nodded, slowly coming to an understanding. He decided to ask a question that had been burning in his head for a long time. “Teacher, why do you care so much about me? Why did you choose me to become a demon?”

Kokushibo was again silent for a long moment. Then he stopped walking and turned to face the younger demon. Yellow eyes bored into his own turquoise ones. “Very well. You deserve to know… the truth.”

Muichiro blinked and waited.

“My name as a human… was Michikatsu Tsugikuni. You and your brother… are descendants… of the child I left behind in the Tsugikuni family. In other words… you are my descendants.”

A jolt of shock ran through Muichiro, his eyes going wide. And yet, it wore off quickly, or maybe he hadn’t truly been shocked at all. A part of him… felt like he already knew. Had always known. Their mental connection, Gyokko’s comment on him being Kokushibo’s progeny, the strange pull he felt between them; it all made sense now. Hundreds of years had passed, diluting their bloodline, but the blood of demons still bound them.

“You… You were a demon slayer too, once, weren’t you?” He already knew the answer, but he asked regardless. Master Kagaya had said they were descended from the First Breathers. He wasn’t wrong, but… they weren’t descendants of Sun Breathing. Their legacy laid in the light of the moon, tainted by demonic blood, tainted by betrayal.

“I was.” The Upper Moon made no attempt to justify himself.

“So you betrayed everyone? Why?”

“It was… necessary… to escape the mark’s curse.”

Muichiro’s blood ran cold. Then, what he thought was a demon crest was… “You had the mark, too?”

“I did. Those who earn the demon slayer mark… are doomed to die by the age of twenty-five. I have seen it… time and time again.”

“…Then, the only way to survive is to…”

Kokushibo nodded. “Only by becoming a demon… can one survive the mark’s curse.”

Muichiro’s gaze drifted from his teacher to the ground at his feet, a heaviness settling over his heart. Then, there was no other option? Kokushibo was over four hundred years old; if there was another way to break the curse, surely he would have found it? The only way his big brother could survive was if he became a demon like Muichiro.

But, could he do that to him? Even if it was to save his life, could he betray Yuichiro and the Corps…?

…No, he already knew his answer. Once, a long time ago, all he had was Yuichiro. But that had changed. They had true friends, and hopes for the future. Hopes in which they were both humans, growing up and growing old together. And maybe the mark’s curse would cut all that short, but…

…but a short life as a human was better than eternity as a demon. And he knew Yuichiro felt the same.

“…No, I… I can’t accept that. To become a demon, even if it’s to live… I can’t accept that as a good reason! You’ve killed countless people, betrayed the demon slayers, and left behind your family, all just to survive? That’s so selfish!”

Kokushibo hummed and closed his eyes. “Yes, perhaps it was.”

The Upper Moon’s quiet acceptance only angered Muichiro more. “…Do you even care about us as your family? Or is us being strong all that matters to you?”

That finally got a reaction out of his ancestor. Kokushibo’s eyes snapped open, and he almost looked shocked. “I…” But he stopped, seeming unable to answer.

Muichiro swallowed a lump in his throat. “If you really cared, you’d stop this. Help us stop Muzan and make a better world!”

He knew he was making a ridiculous request. Anyone else would call him crazy or stupid to try and appeal to the humanity of Upper Moon One, of all demons. But even if he knew Kokushibo was a terrible, maybe even irredeemable person, Muichiro still couldn’t bring himself to hate him. Perhaps he was just too softhearted, but that’s the kind of person he was.

And maybe his hope was blinding him, but Kokushibo almost seemed to be considering his words. “…If only… it was so simple. But the final battle approaches… and I have long since lost the right… to choose for myself.”

His hand moved to his sword’s hilt, and Muichiro stepped back, the sting of disappointment overridden by battle instinct kicking in. A mist sword formed and he readied himself for the Upper Moon’s first move.

“Muichiro! Muichiro, where are you?!”

Yuichiro’s voice, far off but all too clear, reached his ears. Two quick stabs of shock and fear ran through his heart. No, he couldn’t come here! Not now! Muichiro took his eyes off the Upper Moon for a second, fear for his brother overriding reason.

“Yui-” A sharp pain in the back of his neck knocked him to the ground. Kokushibo’s voice came from above, faint as his consciousness slipped away.

“I am sorry… but I can no longer protect you from that man…”

Muichiro couldn’t respond. His vision went dark.

—

Yuichiro ran through the forest, frantic in his search for his twin. How did this happen? He’d only asked Tanjiro to teach Muichiro the Hinokami Kagura to give his brother a new goal to become stronger. No one had expected Muichiro to go into a panic, or for the Devouring Mist to manifest itself to protect him. What had he seen?

Tanjiro and Genya followed close behind him. They were relying on Tanjiro’s sense of smell to find Muichiro, but Yuichiro was faster and too worked up to slow down for them. “He’s just up ahead! He-”

Tanjiro suddenly stumbled, almost tripping over his feet if not for Genya catching him at the last second. Yuichiro slid to a halt, turning to the two. “What are you…!”

Then he felt it. A powerful aura, one that he hadn’t felt in years, but would never forget for as long as he lived. You’ve got to be kidding me! Why is he here now, of all times?!

Yuichiro drew his sword and ran in the direction of the aura, his heart hammering in his chest and praying he wasn’t too late. And then he saw them. The Upper Moon One, Kokushibo, stood with his sword ready, as if waiting for him. And cradled in his other arm was an unconscious Muichiro.

Yuichiro’s heart stopped for a moment; the fear he felt was so great that it froze him in place. His twin looked so small in the Upper Moon’s grasp. “Muichiro…! Let him go!”

Kokushibo's eyes narrowed. Muichiro groaned, his eyelids shuddering, but he didn’t wake. Behind Yuichiro, he heard Tanjiro call out, “Yuichiro, what’s-!”

The Upper Moon’s eyes went wide, a breath escaping him. Then his sword swung out, and a glowing crescent sliced across the ground.

“Look out!” Yuichiro moved before he could think, tackling Tanjiro to the ground as the crescent cut right through the space where the older boy had just stood. Just behind them, Genya stumbled back in surprise before pulling out his gun with a growl and pointing it at the Upper Moon.

“Nakime, take us back!” Kokushibo called out, and Yuichiro’s heart dropped.

“No! Muichiro!” He pushed himself off of Tanjiro and leapt towards the demon. Genya fired a bullet at the same time as the sound of a biwa rang through the air. But neither reached him. A door appeared behind the demon, and he stepped through. Then the door closed, and Kokushibo and Muichiro disappeared in an instant, as if they’d never been there at all.

“Muichiro!” Yuichiro fell to the ground, hands grasping the grass where the demon had just stood, begging for an answer even though he knew he wouldn’t get one. This couldn't be happening; his little brother, his twin, his other half, he was right there just a second ago! He couldn’t be…!

Tanjiro and Genya ran up behind him. “What the hell… You’ve gotta be kidding me…” Genya muttered in disbelief. “He’s-”

“Shut up!” Yuichiro screamed, his voice cracking. “Don’t you dare...!”

If he finished that sentence, Yuichiro knew he would break. His whole world was crumbling as he tried to deny what was right in front of him.

“Yuichiro-” Tanjiro’s hand touched his shoulder, and Yuichiro jumped.

“Don’t touch me!” He slapped his hand away and turned back to the spot where his brother had just been. His heart hammered in his chest so hard that it hurt, and a wave of dizziness and nausea swept over him. He couldn’t breathe, couldn't think. He couldn’t do anything but stare at the empty space in front of him.

How did this happen? Just an hour ago, everything was fine! How did things end up like this?

He couldn’t believe it. He didn’t want to believe it!

“Muichiro!” he cried again, praying that this was all just some horrible nightmare that he’d soon wake up from. But his prayers went unanswered, his awful reality refusing to change.

Muichiro was gone.

—

A/N (3/23/24): We have art! A huge thank you to TonyPhan27 for this amazing art of this chapter’s climatic scene! It looks awesome!

Chapter Text

He was looking down at himself.

A young boy in a mist-patterned yukata, hair and clothes caked in blood, cuts all over his slender, frail arms and legs. A human, yet he stood over the body of a demon, crushed and torn limb from limb, with nothing but a hammer and hatchet in his trembling hands.

The boy looked up at him, eyes lifeless but his face contorted with rage. He raised the hatchet and swung, but he caught the tool effortlessly, its dulled, bloodied edge not even cutting into his skin.

The child’s strength left him, and he collapsed, falling forward. He moved without thinking, catching the boy in his arms, turning him so that he was facing up. Even now he struggled weakly, the mindless anger never leaving his face. His eyes peered into hazy teal irises, watching as they slowly closed and his breathing grew shallower by the second.

He was dying; that much was undeniable. The injuries and extreme exertion needed to fight back against a demon were too much for his small body to handle.

But that could be changed.

Slowly, he shifted the boy and raised one of his arms. A claw traced across his palm and drew a line from which precious blood spilled, dripping into the boy’s barely open mouth.

Then he waited. And as the child began to writhe and scream in his arms, changing into something more than human, he turned his eyes up to the moon above.

The moon gazed back, and shone down on a new beginning.

--

Wake up!

You aren’t safe here! Wake up!

Muichiro’s eyes snapped open, and he immediately wished they hadn’t. The dream faded away, and an unfamiliar sight greeted him. He was on some sort of large wooden platform, with a vast stretch of emptiness on all sides. His surroundings resembled the inside of a castle, if said castle was constantly shifting and ignoring all sense of space and logic. Floors, walls, ceilings, all moved without purpose, the lantern lights disorientating. He couldn’t see the end; this changing mass of senseless architecture seemed to extend on and on into infinity.

Where was he? The last thing he remembered was meeting Kokushibo in the forest outside their estate, and preparing for a battle. Then he heard Yuichiro’s voice and… and nothing.

On instinct, he tried to sit up, only for a sudden pain to surge through his arms and legs. He looked down, and saw his hands and feet ensnared in tendrils of flesh. Bulbous eyes blinked up at him, and sharp teeth sunk tighter into his limbs with each frantic movement. Trickles of his blood burned the fleshy masses, but they stayed rooted in their spots, barely reacting.

“Do not struggle…” His teacher’s voice came from his right, and Muichiro turned to see Kokushibo kneeling by the edge of the platform. His face was as unreadable as ever, but Muichiro noticed a claw-like scratch across his cheek and one eye. “Those tendrils… are designed to drain your blood… to prevent use of your Blood Demon Art. You cannot escape them.”

Muichiro grit his teeth, but he stopped struggling. “…Where am I?” he asked Kokushibo, trying to get his breathing under control and not betray how scared he really was.

“You are in the Infinity Castle… It is a space created by a Blood Demon Art… separated from the reality that you know.” Kokushibo answered. “It is here… that the Demon King resides.”

Muichiro found his explanation hard to follow. A space separated from reality? How could that be possible? But despite how extraordinary the idea sounded, it made sense. It was no wonder the Demon Slayer Corps were never able to find Muzan if he’d been hiding in a place like this for centuries. He couldn’t even fathom how a place this big could exist. The demon that created it must be extremely powerful.

The twang of a biwa filled the air, startling him. Suddenly a second platform rose up in front of his own to reveal the source of the fleshy tendrils binding him. A powerful aura shocked him to his core; Muichiro found himself gazing up at who he was certain was Muzan Kibutsuji himself. The demon’s form was innocuous, a black-haired man no older than his early twenties, but his eyes, those ruby red, snake-like eyes, spoke of boundless cruelty behind the facade. The tendrils binding him extended from the Demon King’s hand as he slowly approached the Mist Hashira.

“You’re awake. Good, let’s get started then.”

The contempt in his voice was palpable. Muichiro could only snarl back, his heart thundering in his chest, his instincts screaming danger.

“Leave us, Kokushibo. I wish to speak to our new ‘guest’ alone,” Muzan instructed.

But Kokushibo hesitated to obey, his face twitching almost imperceptibly. Muichiro watched him, wishing so desperately to know what he was thinking. Was he worried about him? Did he have any regret for what he’d done?

After a few seconds, Muzan sighed. “…I won’t kill him. Return in ten minutes; that will be enough time.”

The Upper Moon One seemed to accept that compromise. He stood and bowed, and with another twang of an unseen biwa, he was gone, leaving Muichiro truly alone.

Alone except for the king of all demons standing before him. The tendrils kept Muichiro bound on all fours as Muzan stood before him, red eyes looking judgingly upon him.

“How did you do it?”

“Wh…What?” Muichiro asked, not understanding. But the tendrils’ teeth suddenly sunk deeper, and he bit back a cry of pain.

“I don’t like to repeat myself,” Muzan told him, eyes narrowing. “You escaped my control, and found a way to devour other demons and take their power. You’ve never eaten a single human, and yet somehow you’ve attained a power that only an Upper Moon should be capable of. How did you do it? What makes you different?”

“I… I don’t know,” Muichiro hissed through the pain. Those were questions he couldn’t answer, and even if he could, like hell he would tell this demon anything. Muzan didn’t seem to appreciate his response, his displeasure all too clear on his face.

“Hmph… What does Kokushibo see in you?” The tendrils suddenly jerked upward, forcing Muichiro to his feet. He bit back another cry of pain and forced himself to look Muzan dead in the eyes, refusing to show fear before this monster.

“Make no mistake. If not for Kokushibo’s… favoritism… towards you, I would kill you where you stand. I do not take disobedience lightly,” Muzan growled, cold malice laced into every word. He reached out, taking Muichiro’s face in his hand, claws digging into his skin. The tendrils’ teeth sunk in even deeper.

“Fortunately, I have ways to make a disobedient dog come to heel.”

—

Kokushibo reappeared in another place, the biwa’s twang still echoing in his ears. His training arena stretched out before him, but he sensed two presences already here. He knew who they were from their auras alone, and the cracking sound of iron-hard flesh against fragile wood only confirmed what he knew.

“Akaza, Douma… Why are you here?”

He walked towards the center of the arena, finding the Upper Moon Three, Akaza, striking his fists against a wooden pillar, the column splintering against the force of his punches. Douma, the Upper Moon Two, rested against another pillar. He opened rainbow-colored eyes and smiled at the six-eyed demon.

“Lord Kokushibo, you’re back! I’m so glad, it’s been so lonely without you!”

Kokushibo ignored him and raised an eyebrow at Akaza. Seeing the two of them together and not fighting was surprising, to say the least. Akaza just looked annoyed. “He won’t leave, so I’ve just been trying to ignore him.”

“Now, Akaza, is it so wrong for me to want to enjoy your company?” Douma asked, still smiling.

“Yes. I don’t want anything to do with you.”

“Why are you two here?” Kokushibo asked again, his patience wearing thin.

Akaza grunted and stopped his assault against the pillar. “…So, you finally brought the kid, huh?”

Kokushibo hummed In affirmation. “I have.”

“Oh, are you talking about the child you brought in? He’s adorable! Much cuter than that other demon slayer you converted,” Douma chuckled.

Akaza’s frown deepened. “Weren’t there two of them? What happened to the other one?”

“He is alive,” Kokushibo responded. “He remains with the demon slayers.”

“Why’s that? You were told to bring back both of them, weren’t you?”

“There were… complications.” It was a non-answer, and they all knew it. Kokushibo could have easily slaughtered the two boys, even the one with the hanafuda earrings who startled him so, and taken Yuichiro if he wanted to. But therein laid the problem. A part of him hesitated; he knew that child would never survive here. Not as a human, anyway.

“My, my, Lord Kokushibo, I didn’t take you as one to make excuses for yourself. Surely Lord Muzan wasn’t too pleased with your disobedience, hmm?” Douma grinned, a sinister edge to his tone.

Kokushibo’s only response was the narrowing of his eyes. The pain of his body slowly breaking down, cell by cell, was a transient suffering, one that he would forget eventually. But the fury and spite in his lord’s eyes as he looked at the unconscious Muichiro, promising retaliation twicefold for Kokushibo’s failures, would stay with him for much, much longer.

Akaza glared at Douma, then turned his gaze to Kokushibo, an ominous tone in his next words. “You know what Muzan’s going to do to that kid, don’t you?”

Kokushibo didn’t answer. Akaza stared at him for a while longer, but as the silence continued, he huffed and turned away.

“Well, whatever. It’s not my problem. I only came here because I was curious. But I’ll say this: I feel bad for the kid, having you as his family.”

With that, Upper Moon Three walked away. Kokushibo watched him until he was gone, feeling an indignant anger at being spoken to in such a way by his lesser. It was disrespectful… and yet, he couldn’t say that Akaza was wrong. He had already left behind one family, and he was ill-suited to care for another.

Upper Moon Two stood up and opened a fan, holding it over his face. “Akaza can be so rude, don’t you think? But I’m excited, personally! Your own descendant, and a demon who's never eaten humans; how intriguing! Muichiro, wasn’t it? I can’t wait to get to know him!”

Then Douma too departed, leaving Kokushibo alone. But he barely acknowledged him, still lost in his thoughts. Yuichiro and Muichiro, his descendants… were they family? Did he think of them that way?

He couldn’t stop thinking about it. It was a question he couldn’t answer.

But when Kokushibo remembered his lord standing before Muichiro, the child bound and terrified despite his brave attempts to hide it, his heart felt the stirrings of regret.

—

“I’m afraid I have unfortunate news to report. Last night, our Mist Hashira, Muichiro Tokito, was captured by Upper Moon One.”

Amane’s words were met with a tense silence from the seven remaining Hashira. Mitsuri had her hands over her mouth, looking like she was about to cry, while Sanemi silently seethed with anger. The others had various grave expressions on their faces. As soon as the emergency meeting had been called, they all knew that something was horribly wrong.

Yuichiro barely paid any of them any mind. It was all he could do to keep from falling apart right there, to keep a strong face up in front of his companions. He felt their eyes on him, but he refused to acknowledge anyone, his gaze trained firmly on the floor.

“How did this happen?” Sanemi asked, his temper barely kept under control. “Did the Upper Moon find the Mist Estate?”

“From our understanding, Muichiro was far away from the Mist Estate when he encountered Upper Moon One. We do not believe the Mist Estate’s location was compromised,” Amane explained. “Nonetheless, it may be best to put the quick movement training on hold, for the time being.”

Yuichiro flinched, recognizing the hidden intent behind her words. Muichiro was gone, and Yuichiro himself was in no state to be training anyone right now.

“That won’t be necessary. I can handle the quick movement training alongside my own training,” Obanai spoke up. Everyone looked at him in surprise; even Yuichiro snapped out of his daze, thinking for a moment that he had misheard him. Obanai, who barely tolerated working with the lower rank slayers in the first place, was volunteering to take on the twins’ portion of the training?

But the dark, somber look in Obanai’s eyes was unmistakable. Yuichiro suddenly remembered that, despite the Serpent Hashira’s aversion to people, he had been fond of Muichiro. Even Kaburamaru seemed sad, the snake slumped over Obanai’s shoulders.

“But, what’s going to happen to Muichiro?” Mitsuri asked, bringing everyone back to the topic that no one wanted to consider, but which had to be addressed.

“If Muzan has captured him, then I do not believe that their intention is to kill him,” Gyomei said. No tears fell from his eyes, his expression gravely serious.

“Isn’t that a bad thing, though?” Sanemi asked. “If they haven’t killed him, it’s because they want something from him. Tokito knows the locations of the Headquarters and the other estates; if they get that info out of him, none of us will be safe.”

“I think it may be worse than that, actually,” Obanai spoke up.

“What do you mean?” Shinobu asked, but her solemn expression suggested she already had an idea.

“Muichiro is a demon, and a powerful one at that. Don’t you think Muzan would want someone like that on his side? He may try to turn him against us.”

Shinobu’s expression hardened. Mitsuri let out a gasp, Sanemi growled wordlessly, and Gyomei and Giyuu both remained silent but tensed. But Obanai’s words spurred a rush of protective instinct in Yuichiro, who grit his teeth and spoke for the first time since the meeting started. “No, Muichiro wouldn’t… Muichiro wouldn’t do that! He would never betray us!”

“I didn’t say he would do so willingly,” Obanai said. His tone was soft but his words were like daggers in Yuichiro’s heart. “But Muzan is connected to the demons he creates, including Muichiro. What do you think could happen now that he’s in his clutches?”

Yuichiro couldn’t say anything to that. Because Obanai’s words made sense, and if he was being honest, it was the most likely possibility. Kokushibo had called Muichiro his student, and on that night two years ago, he’d attacked them with the intent to bring them both to Muzan. And now he’d succeeded, at least partially, and Muichiro was alone and at the mercy of the Demon King. Yuichiro couldn’t bear to imagine what Muzan might do to his brother. And the mere possibility that he might turn Muichiro against the Corps, that he might be forced to fight his twin, forced to kill-

“Yuichiro, breathe.” Amane’s calm, soothing voice and hand on his shoulder snapped him out of a haze of growing panic. He hadn’t even noticed his breathing had accelerated. He fought to take full, deep breaths. Slowly, his head cleared and he could focus again, even if he couldn’t bring himself to speak. He just nodded his head to show that he was listening.

Amane settled back in her seat and continued. “We’ve been told that Upper Moon One was able to escape with Muichiro by going through a door that appeared and vanished in an instance. This door is certainly a Blood Demon Art, but we don’t know where it led to. It pains me to say this, but we have no idea where Muichiro could have been taken.”

Yuichiro turned away, grimacing. So they weren’t going to search for him. There was no one they could spare, and they didn’t have any leads on Muichiro’s location. It was to be expected. But that didn’t stop the bitter feeling he felt boiling up inside him.

“I urge you all to continue your training, but exercise caution. We cannot be sure when Muzan or his remaining Upper Moons will strike next,” Amane said somberly.

The Hashira gave their acknowledgements, and the meeting concluded. Yuichiro stayed where he was, once again feeling their worried gazes on him as they left. But he didn’t want to speak to any of them; he feared he’d snap if he had to endure any words of sympathy. Soon the only ones left in the room were him, Amane, and her daughters. Then the Master’s wife motioned to her children, and they departed as well, leaving just the two of them.

“Yuichiro?” Amane prompted him to speak. He was sure she must be very busy, but she waited patiently for his response.

“…I failed him.” Yuichiro said in a voice barely above a whisper. “I promised to protect him and I couldn’t do that.”

No, more than that, his little brother was in the clutches of their enemies because of Yuichiro. None of this would have happened if he hadn’t suggested that Muichiro learn the Hinokami Kagura in the first place. But he had, and now Muichiro was gone, far beyond his reach. Who knew what was happening to him? It was unbearable; the terrifying uncertainty was tearing him apart.

“Yuichiro, I understand your fear-”

“Do you? What the hell can you understand?” Yuichiro’s voice rose. “Muichiro is in danger and I can’t do a damned thing about it! How can you possibly understand what that feels like?!”

Yuichiro knew he was being unfair. But without Muichiro, he couldn’t calm down. Old habits die hard, and anger was the only means by which his shattered heart could protect the fragments that remained. “Telling us to just go back to training like nothing’s changed… I can’t do that! I can’t just go about living when I know he’s in danger! I have to find him!”

“And how will you do that?” Amane asked. “Upper Moon One escaped through a Blood Demon Art. Kibutsuji and his Upper Moons have evaded detection for hundreds of years; it is likely that wherever they took him is impossible to access by normal means.”

“I don’t care how impossible it is! You can help me or not, but I’ll find him myself if I have to!”

“Yuichiro, I never said we wouldn’t look for Muichiro. But you must calm down and think this through. You have no idea where he is. Furthermore, what would you do if you did find him? I’m not doubting your skills, but you would be facing Upper Moon One alone. Do you think you can win that battle?”

“I…”

“How would Muichiro feel if you were to get hurt trying to rescue him? Think about how it would affect him to see you like this. You need to stay calm, for his sake.”

“I know that!” Yuichiro snapped, but the reminder of Muichiro’s feelings succeeded in making him take a moment to think. How would Muichiro feel, seeing him so panicked? He took a breath and tried to rein in his emotions. “I… I know that already. I just… What else am I supposed to do? I can’t just do nothing…!”

He squeezed his eyes shut, trying to keep his tears from falling; to cry in front of Amane would be mortifying. But then he heard her move closer, and her arm gently wrapped around his back and shoulders.

“It’s not doing nothing. It’s making a plan, considering every angle, and not jumping into Kibutsuji’s trap. Kibutsuji is still searching for this place; he expects us - expects you - to make a desperate move and reveal ourselves. I assure you, we will do everything we can to find Muichiro, but you mustn’t let him get what he wants.”

Her quiet logic was a direct appeal to him; Yuichiro had always been a rational person. She was right, and he couldn’t deny that. But it was so unfair. His little brother was in danger and his best option now was to sit around and wait. Some big brother he was; a complete and total failure.

“Please, at least stay here for tonight. You need to rest,” Amane pleaded as he tensed up again. “Don’t do anything reckless, Yuichiro.”

Yuichiro growled; he wanted to argue, but he couldn’t find the words to try. Just imagining Muichiro in Muzan’s clutches, afraid and in pain, made his blood boil but… he wouldn’t be any good to Muichiro if he got himself hurt or worse. Against every instinct in his body, he relented to Amane’s request.

“Fine, but only for tonight. After that…”

He stopped; he wasn’t sure what he would do after this. There just wasn’t any easy answer. Amane moved her arm away slowly, and a part of him cried out at the loss of her warmth. For just a second, he was tempted to seek out that warmth again, like a child wanting his mother’s comfort.

But she was not his mother. His mother was dead, as was his father, and now he feared that his twin brother would soon follow. New tears formed in his eyes, and he stood up, long hair falling over and hiding his face.

“I’m going to our room. Don’t bother me.”

Our room. Even when it was only him here, he still thought of it as theirs. But, there was no reason for him not to think that, right? Muichiro wasn’t dead. He couldn’t be.

He prayed to the gods, to Buddha, to anyone, even though they’d never once heard him before. Yet still he prayed, begging for them to listen, begging for his little brother to just be safe.

—

But his prayers were never answered.

Tomorrow turned into a day, which turned into a week, then two, then three. No trace of Muichiro could be found, no matter how hard or how far the Kasugai crows searched. Even Tamayo was consulted for help, who all but confirmed Amane’s theory that wherever the demons were keeping him was a place inaccessible by normal means. But no matter how impossible it seemed, Yuichiro couldn’t give up on finding him. He couldn’t.

But this wait was killing him. He tried to be patient, to follow Amane’s advice. But he felt like he was just wasting time. His mind was fraying with each passing day that Muichiro wasn’t by his side. He’d never been so alone before; it felt like half his body was missing, his mind trapped in a stormy sea of tumultuous thoughts. Where was Muichiro now? Was he hurt? Was he scared? Was he thinking about Yuichiro, the way Yuichiro never stopped thinking about him?

The only times his mind was quiet was when all of his energy and focus was committed to his training. And so he trained, every waking moment of the day, until he was ready to drop from exhaustion. Until he felt his lungs seize up and tasted blood in his mouth. And then he forced himself to keep training, only his anger keeping him going, because he wouldn’t let his human limits stop him from getting Muichiro back.

Yuichiro bashed the training dummy in front of him with such fierceness that it was barely hanging onto its post after only a few strikes. His bokken shook in his hands, and as he brought it down for another swing, he heard a crack as it connected with the dummy. His eyes widened as he looked at the snapped bokken, its upper half clinging on by a mere splinter.

It was far from the first training sword that he’d broken today. And yet, looking at it was suddenly too much for Yuichiro to handle. He screamed and swung the remains of the bokken at the dummy, knocking its head clean off, before lifting his foot and kicking the body off its post. He stood over the decapitated dummy, chest heaving with rage, before some semblance of rationality returned. He huffed and tossed the bokken aside, walking towards the pile of replacements he’d brought outside for this very purpose.

“Yuichiro, shouldn’t you take a break now?” Ginko’s voice, uncharacteristically soft, came from behind him. He turned to look up at the tree she was perched in, his glare softening slightly. The poor crow had not taken Muichiro’s kidnapping well. She looked almost sickly, having grown thinner over the weeks, her feathers ruffled from constant worry. She missed him too, just like he did.

But the aching in his heart when he thought about that was too much to bear. “I don’t need a break. What I need is to get stronger.”

“But you’re hurting yourself,” Ginko tried to reason with him.

Yuichiro rolled his eyes. “I won’t get any stronger if I don’t push myself to my limits.”

Ginko flew down to land on his shoulder, where she nudged her head against his cheek. “But you need to go on patrol tonight, remember? Please, get some rest first!”

Right, patrol. It felt so pointless; even after all this time, not a single demon had been spotted since Nezuko conquered the sun. None except Upper Moon One, of course. But patrols were an opportunity for him to go searching for Muichiro himself. They never yielded any results, but at least he could feel like he was doing something, even if he had to return by sunrise lest he worry everyone even more. And while he couldn’t care less for their concerns, he could certainly do without their constant hounding.

“You should listen to her, you know.”

Speak of the devil; Yuichiro sighed. “Not you too...”

He turned to see Aoi staring sternly from the open door. She stepped onto the engawa and approached him, a look of disapproval on her face. “I’ve told you this a hundred times already-”

“So why bother telling me again?” Yuichiro asked flatly.

“Because maybe you’ll listen this time!” she snapped. “You’re not doing yourself any good by pushing yourself half to death! It’s almost noon; have you even eaten anything today?”

Yuichiro looked away, not willing to answer that question. But his silence was answer enough for Aoi, who groaned. “Come inside, I’ve got lunch ready.”

“I’m not hungry. And I didn’t ask for you to make me anything, either,” Yuichiro bit back, his irritation growing by the second. This was just another example of everyone inserting their care and concern where it didn’t belong. Where it wasn’t wanted. He waved Ginko away and walked past Aoi into the estate, which was long empty but for the two of them. The manor had always been too big, but now that his brother was gone, the loneliness contained within was almost too much to bear.

He heard Aoi sigh, then footsteps as she followed after him. “You know we’re all just worried about you, right?”

“Of course I know that. You make it obvious every day.”

Yuichiro was not an idiot. He could tell that everyone was treating him a little more delicately, paying him a little more attention to make sure he didn’t run off and do something stupid. They thought they were being subtle, but all their little ‘subtleties’ added up quickly. From Mitsuri and the Butterfly girls stopping by with extra sweets, to Uzui making time for one-on-one training, to Tanjiro sending him letters about anything and nothing as he continued his training at the other estates.

And then there was Aoi, who had taken it upon herself to move into his home and make sure he didn’t work himself to death, per her own words. She would cook, clean, and force him to eat and sleep at normal hours. In any other state of mind, he might have appreciated her company.

But Muichiro was still missing.

“Muichiro wouldn’t want you hurting yourself like this,” Aoi said.

Yuichiro flinched, the mere mention of his brother’s name a stab to his heart. “Don’t talk about him like that, like he’s already dead.”

“I-I wasn’t…!” Aoi stopped, her voice noticeably calmer when she spoke again. “I’m sure he’s alive, but he’s not here now. And until we can bring him back, you have to take care of yourself. All the training in the world’s not going to help you or him if you collapse from exhaustion in the middle of a fight.”

“I know that!”

“If you know, then why won’t you listen?”

Yuichiro grimaced, unable to answer. Or rather, he didn’t want to, knowing that she wouldn’t accept his answer. He started walking faster, hoping to convey that he didn’t want her following, but she either missed or ignored his intent and chased after him anyway.

“Hey, Yuichiro!”

“Stop following me.”

“Ugh, you can’t keep doing this! Ignoring everyone and shutting us out; it isn’t good for you!”

“You know what else isn’t good for me? Waiting around here and doing nothing while Muichiro is in danger, but the rest of you don’t seem to have a problem with that!” Yuichiro could feel his temper flaring up again, and he walked even faster. His and Muichiro’s room was just up ahead, and if he could get inside, he could shut Aoi out before his anger reached a breaking point.

“Come on, Yuichiro, that’s not true and you know it! We all care about him and want him to be safe just as much as you do.”

Yuichiro froze just as he was about to slide open the bedroom door, an almost dizzying feeling of rage rushing through him. They cared just as much as he did? That was bullshit; whatever concern they felt for Muichiro couldn’t even compare to the constant fear and grief that was eating him alive every single day. Where the hell did she get off saying something so ignorant and arrogant?

No, she didn’t mean it like that. She’s just trying to help, he tried to remind himself. Getting mad at her won’t do any good.

But as much as he tried to be a rational person, he was still only human.

“You’re wrong,” he bit out, using all of his self-control to keep his hand on the door and not face Aoi directly. “You don’t care about him the way I do. Muichiro is more than just my brother; he’s my other half, my reason to keep going in this horrible, unfair world. Without him, I’m lost. There’s no way you can understand that; to even think that you can…!”

Aoi gasped; she seemed to realize the mistake she made. It was a while before she spoke again, giving Yuichiro precious seconds to breathe and try to calm down. He suddenly felt a headache coming on, the lack of food and sleep taking its toll.

“I’m sorry, I shouldn’t have said that,” Aoi apologized. “You’re right, I can’t understand exactly what you’re feeling right now. But I’ve lost people too; we all have. You’re not alone here, Yuichiro. Please, talk to us. We want to help.”

Yuichiro felt the stirrings of guilt in his heart, but as always, it was drowned out by the flood of his own pain. “The only help I want is getting Muichiro back!”

“I know, but that isn’t possible right now. Even Lady Tamayo said that Muichiro is somewhere humans can’t go, right? There’s only so much you can do-”

“I know that! That’s the problem! I can’t do anything! Muichiro is in the hands of our enemies and I can’t do a thing to help him! I’m completely useless!” Yuichiro’s head snapped to face her, and he took a step forward. Aoi stepped back at the wild look in his bloodshot eyes; he knew he was scaring her. But three weeks of anger and frustration and grief were boiling over, impossible to hold back any longer.

“You’re not-”

“Shut up!” He didn’t want to hear any more sympathy; he didn’t deserve it. “Stop trying to help me! Stop trying to make me think about myself! I can't do that; it isn't right! I don’t get to be happy as long as he’s suffering!”

His outburst was met with stunned silence. Aoi said nothing, at a loss for words. Yuichiro glared at her a moment longer, and then his fury drained away and he realized what he’d said. He looked into her eyes, seeing sadness and worry in her gaze. There was no hurt or anger, and that just made him feel worse.

He stepped back and opened the sliding door at last, unable to bear her gaze on him any longer. “…Just go away. I don’t want your help, and your kindness is wasted on someone like me anyway.”

“Huh? Yuichiro-!”

But Yuichiro just stepped inside and slammed the door shut behind him. For a while, he just stood there, trying to get a handle on his breathing. Aoi stayed outside the room for a few moments longer before turning and walking away. Once he was sure she was gone, he slid down to the ground, back slumped against the door.

What the hell was wrong with him? Not only had he yelled at Aoi, but he said too much about himself as well. His frustration was endless, but his body and mind alike were weak with exhaustion. His stomach growled and his headache pulsed, but there was no way he could go out for food or medicine and risk seeing Aoi after all that.

His eyes drifted shut, his tiredness catching up to him. For now, he would just sleep, and face the world another time.

—

A sea of mist stretched out without end. Yuichiro looked around, feeling a sense of familiarity, until it hit him. He’d been here before, lost in this fog. Then, this was a dream, wasn’t it?

He stepped forward through the mist, not sure where he was going. But he had a feeling; his brother was here, somewhere. “Muichiro? Can you hear me?!”

But his voice was swallowed up in the thick fog. He scowled and called again, louder, “Muichiro! It’s me, Yuichiro! Where are you?!”

The mist seemed to shudder, but otherwise gave no response. Until his ears picked up something far in the distance. His heart sank as he recognized crying, familiar crying at that. “Ugh…! Hold on, Muichiro, I’ll find you!”

But before he could move, the mist turned from tranquil white to seething blood red, and something darted through the fog. Yuichiro froze and reached for his sword, drawing it and standing in a defensive stance, trying to track the dark shape within the mist. He knew this had to be a dream, but he still felt like he was in real danger.

It moved again in his peripheral, and he turned, keeping his senses open. Its movements seemed random, but there was a pattern to it; he knew that because he recognized this move. Another dash in close to bait an attack and- now!

Yuichiro spun fully around and raised his sword just as the dark shape leapt out of the mist. His blade met its claws, and it flipped over him to land on his other side. Yuichiro turned around, watching as it stood up and revealed itself. But as it looked up to face him, he gasped, a cold jolt like an electric shock running through his body.

His attacker’s features weren’t concealed in the mist; fully exposed, it was nothing but a dark shadow. A shadow of what was unmistakably his twin brother. Six turquoise eyes glowed with an icy hostility that unnerved Yuichiro even more than its uncanny appearance.

“What are you?” he asked while keeping his sword raised. This was not Muichiro; he could still hear his twin’s cries deep inside the fog.

The shadow didn’t respond. Its eyes narrowed, and it flexed its claws before lunging towards him. Yuichiro sidestepped the attack, and it leapt back into the fog. The shadow moved much like Muichiro himself; quickly and evasively, hiding in the mist and only revealing itself for quick strikes. It was nothing that Yuichiro couldn’t handle, having sparred with his brother more times than he could count, but he noticed that the distant crying was becoming fainter, the shadow attacking whenever he tried to move towards the sound and pushing him back. He realized that the shadow was driving him away from Muichiro.

As it lunged again, Yuichiro went on the offensive. “Mist Breathing, Second Form: Eight-Layered Mist!”

But the shadow’s form dispersed, his slashes cutting through a dark cloud that was more like smog than mist. The cloud retreated and reformed several feet away, the shadow of his twin glaring at him.

Yuichiro glared back and readied his blade for another strike. “Let me through! I need to help Muichiro!”

I don’t need help from a failure of an older brother.

Yuichiro stumbled, almost losing his balance if not for years of training kicking in. The shadow raised its hand, and a furious roar echoed within the fog as several mist beasts burst forth. Yuichiro regained himself and dodged just in time before they crashed down where he’d stood. But the mist was everywhere, and more lashed out, forcing him to move. Muichiro’s voice grew fainter and fainter.

He avoided another beast, and suddenly the shadow was in front of him. On instinct, he stepped out of range of its claws, only for a dark blade to knock his sword from his hands. Defenseless, the shadow’s hand gripped his throat and slammed him to the ground. Yuichiro could only look up into its blazing turquoise eyes.

The shadow’s sword swung towards his neck.

—

Yuichiro’s eyes snapped open, greeted only by the darkness of his empty bedroom. The mist and the shadow were gone. He sat up straighter and took deep breaths to calm his racing heart.

What the hell was that? He’d had dreams - nightmares- like that before, with something attacking him in the red fog, but this was the first time he’d actually seen what attacked him. A shadow that resembled Muichiro. What did it mean? He hadn’t expected it to actually talk, let alone have a voice so much like Muichiro’s. But the cold, harsh cadence was so unlike his little brother; if anything, it almost sounded more like himself.

The shadow’s words came back to him. A failure of an older brother; that’s what it had called him. But it wasn’t wrong. He did fail Muichiro. He failed to keep his promise and left him alone in the hands of Muzan himself.

Still, that shadow worried him. Inside the dream, he somehow knew that he’d been closer to finding Muichiro than any of the crows searching for him. But the shadow stopped him. Why? Was it protecting him? Or was it keeping him trapped? He didn’t know, but the bad feeling he had refused to go away.

Muichiro was in danger, and he was running out of time.

Yuichiro stood up, pushing through another sudden headache. He didn’t feel rested at all, but he’d already wasted enough time as it was. Tonight, he was going to take action. It didn’t matter if Muichiro was somewhere that humans couldn’t go. The solution was obvious from the start, even if no one in the Corps wanted to consider it. The only way he was going to find Muichiro was by finding the one who took him in the first place.

To save his brother, he needed to find Kokushibo.

Chapter Text

It hurts. Yui…

Blood poured from wounds that wouldn’t heal. His own blood stained the floor below and splashed across the wall behind him, a gruesome sight. Fleshy tendrils with too many eyes and teeth rooted him to the spot, leeching away any strength he had to fight back. Not that he could, with the King of Demons watching his every move, red eyes trained coldly upon him.

Muichiro was tired. He was tired and in pain. But he couldn’t sleep, couldn’t fade out, couldn’t hide from his agony. Muzan wouldn’t let him.

“You’re resilient, I’ll give you that,” Muzan admitted with a scowl. “Most demons in your place would be begging for death by now.”

Muichiro didn’t speak. Talking resulted only in him being hurt more, so he held his tongue. The fog tried to close in around his mind, to dull the pain, but a sharp stab in his heart brought him back to reality. He bit back a scream as ancient blood pushed through his veins and burned away the fog.

Muzan withdrew a needle-pointed tendril and hummed, like he was observing a moderately interesting specimen under a microscope. “Now, now, no hiding inside yourself. You’re staying right here.”

A low growl slipped past Muichiro’s lips. He couldn’t ignore the pain, so he just had to endure it. He had to hold out.

But he was tired. How long has it been? He wasn’t sure; he thought he had these “sessions” with Muzan once a night, but he’d also lost count of how many he’d gone through. Time didn’t matter here.

“You know what you have to do to make it stop,” Muzan said softly, enticingly.

Muichiro shook his head, but it only earned him another needle in his chest and a flood of liquid agony. He screamed; Muzan’s blood burned in his veins, but he didn’t have enough of his own to push back against it. The torture was constant, his blood continuously drained and replaced, leaving him to suffer until his body adapted, only to start the process all over again.

But he couldn’t break. He had to hold out.

For Yuichiro.

Eventually, the torture came to an end, as it always did. Muzan grew frustrated with his refusal to give in, and with a final injection of his blood, the Demon King withdrew his tendrils, letting Muichiro collapse to the floor.

“We’re done here. Nakime, get him out of my sight.”

The sound of a biwa answered his call, and suddenly Muichiro was somewhere else. He quickly recognized his “bedroom”, a small room with only one door. It was empty but for a single futon, and even that was only here because Kokushibo provided it. Though a kind gesture, it didn’t make up for kidnapping him in the first place.

Alone in his dark room, Muichiro shuddered and tried to pull himself together. Literally. His wounds started to close at last, agonizingly slowly compared to his usual speed. He didn’t know how long it’d been since he’d last eaten. The strain of trying to regenerate while deprived of any sustenance made his head throb. His gnawing stomach became harder to ignore in the absence of anything else to focus on; he was so hungry…

Once he stopped bleeding, he crawled over to his futon and lifted it up, pulling out Yuichiro’s haori from underneath. He held it close, inhaling his twin’s scent, careful not to get any of his blood on it.

Where are you, Yui? I hope you’re okay… He held the haori and prayed, as if Yuichiro could hear his thoughts if he tried hard enough. I’m trying to stay strong…

Truthfully, Muichiro was torn. He wanted Yuichiro to come for him, to bring him back home, but he had no illusions about where he was. He was in the Infinity Castle, isolated from the entire world, and surrounded by dangerous, powerful demons. Maybe it was for the best that only he was here. He didn’t even want to think about Yuichiro being put in his position.

A knocking outside his door startled Muichiro, setting his senses on alert. But he soon relaxed upon recognizing the silhouette outside. It slid open, revealing Kokushibo. The demon looked over his ragged form, eyes narrowing ever so slightly.

“Come… walk with me.”

—

“How are you feeling…?” Kokushibo asked as they walked. He kept a fast pace, and Muichiro hurried to not lose the Upper Moon. He wrapped Yuichiro’s haori around himself.

“…It hurts,” he answered simply. He could still feel Muzan’s blood writhing and burning in his veins. He felt the urge to claw off his skin and bleed it out, but he resisted. It didn’t work the last time he tried that, anyway.

Kokushibo had no response, but Muichiro hadn’t really expected one. What would he even say? Sorry? It wouldn’t change anything.

They both fell silent again as Muichiro followed Kokushibo through the castle’s changing hallways and twisting corridors. At seemingly random intervals, the walls would fall away or appear from nowhere to reveal or block off pathways, and occasionally they would stand still and the floor would move on its own, up, down, left, right… Muichiro couldn’t make any sense of it. But Kokushibo seemed to know where he was going, so he simply stuck close.

At some point, they walked over a high up, rail-less path with a multitude of similar paths below it, hanging over a deep pit. He heard growls and snarls, and peered over the edge. On one of the paths below, demons in strange morphed forms stalked along aimlessly. Muichiro remembered when he first came here, how there were some lesser demons who still retained their humanoid forms. But all those demons were long gone, transformed by Muzan into powerful, mindless monsters to use against the slayers.

One of the morphed demons collided with another larger one, and the offended demon roared before descending upon the other in a flurry of claws and fangs. Muichiro grimaced; they were little more than animals, wild and ravenous. Looking at them filled him with revulsion, and yet, he found it hard to look away. The scent of spilled blood made his mouth water and his stomach turn. He really was very… very hungry…

A hand touched his shoulder, and Muichiro felt himself being pulled away. “Pay them… no mind,” Kokushibo instructed him. Muichiro could only nod.

Eventually, they reached a location that Muichiro found very familiar by now. A large space filled with black pillars extending high into the air, a training grounds for Upper Moon One and his student.

Kokushibo walked a distance away before turning back to face him. “Draw your sword.”

Muichiro nodded and took off his twin’s haori to set it down beside a pillar. He formed a white mist sword, readying himself as his Teacher drew his own blade from its sheath.

“This time… I wish to see your skill with the Moon Breathing techniques.”

Muichiro nodded, and then he made the first move, launching himself forward. “Moon Breathing, First Form: Dark Moon, Evening Palace!”

White crescents flew from his blade as he made a blindingly fast slash to disarm his teacher. But Kokushibo still reacted in time, dodging his swing and retaliating. Muichiro stepped back to avoid the blade; though he was still tired, his demonic body was slowly regaining its strength.

“Impressive… though I showed you these forms only once before… you’ve been able to remember and replicate them masterfully…”

Muichiro acknowledged Kokushibo’s praise with another technique that the Upper Moon skillfully blocked. Thus their training continued; he took to the rhythm of sparring with practiced ease, dodging or deflecting Kokushibo’s swings while trying to land a hit against his more experienced ancestor. Sometimes he succeeded, the gap between them having shrunk over the years. He could almost feel proud of his growth, if not for the circumstances that led to it.

But training like this had become the one part of his new routine that Muichiro didn’t dread with all his being. Being able to wield a sword was comforting; he could at least pretend that he had some level of control, even if he knew he didn’t. And Kokushibo was no harsher on him as a teacher than he had been when he first started training him almost three years ago. He didn’t hold back, but frankly, a clean cut with a sword hurt a lot less than the horrible wounds that Muzan inflicted on him regularly.

After an uncertain amount of time, Kokushibo stepped back to allow him a break. The older demon sat down against a pillar, appearing to meditate, and Muichiro gathered his folded haori in his arms before sitting down beside him.

“Teacher?” he asked tentatively.

“Hm?” Kokushibo opened one eye to peer at him, waiting for him to continue.

“Can you tell me more about you and Yoriichi?”

Kokushibo froze, the rest of his eyes snapping open. It was the most emotion he had seen the Upper Moon express in a while. “Why… do you want to know that?”

“It’s just, you were twins, right? Like me and Nii-san,” Muichiro answered. He was curious, and he needed a distraction from the constant pain and hunger. “You’re my ancestor. I want to know more about you.”

Truthfully, Muichiro felt like he didn’t really know anything about Kokushibo. He was his teacher and ancestor, but what did that really tell him? Kokushibo kept his thoughts and feelings guarded so tightly, but he had once been human too. He had an entire life before becoming the demon he was now. He wanted to know more about Michikatsu Tsugikuni.

Kokushibo looked away, his gaze becoming distant. It was a long while before he finally spoke again. “Yoriichi and I were brothers, but… we were never equal.”

Muichiro felt a pang in his heart at that word. Equal. It had been so important to him once. But now he just wanted to be with Yuichiro again, equal or not.

Kokushibo continued. “At the time, twins were thought to be unlucky. As the older twin… I was to be our father’s successor. Yoriichi would have been killed… but our mother convinced our father to send him to a temple… to become a priest instead.”

“So, how did you two become demon slayers?” Muichiro asked.

“As a child, I trained to become a samurai. I trained hard, everyday. Yoriichi was never meant to become one, and yet… he surpassed me instantly. He had a natural talent… from the very moment he picked up a sword. It was such that our father made him his successor… but Yoriichi ran away before that could happen. The next time I saw him… was as an adult years later. I would have been killed by a demon… but he appeared, and beheaded it with no effort at all.”

Muichiro listened carefully. Yoriichi sounded like an amazing swordsman. “So, Yoriichi protected you, and that inspired you to become a demon slayer?”

“Inspired…?” Kokushibo repeated, blinking. His eyes narrowed. “No, I was not inspired by him. I… envied Yoriichi. I wanted his strength and skill for myself. That is why… I chose to become a demon slayer. To surpass him.”

“Why? I thought you wanted to be equals?” Muichiro asked.

“No. To be equal to Yoriichi was… impossible. At every turn, he exceeded me. His was a talent… that no amount of hard work could overcome.” Frustration laced Kokushibo’s tone.

“That’s not true, though. Talent will only take you so far. You still need to train hard to be truly good at something.”

But Kokushibo shook his head. “You did not know him. He was… truly blessed by the gods. I felt… inferior to him.”

Muichiro looked away. He understood that feeling, at least. He remembered when he felt the same, like he would never measure up to his big brother. But he and Yuichiro overcame that; they came to understand each other. He looked back at Kokushibo. “Even so, no one’s perfect. Everyone has things they’re not good at, or things they wish they could do better. I’m sure there were things that you did better than him. He might have even envied you, too.”

“Envied… me? For what?” Kokushibo looked dumbfounded, like the very idea was inconceivable to him.

Muichiro shrugged. “I can’t say since I didn’t know him, but everyone has secrets they keep to themselves, right?”

“I… cannot answer that. I cannot imagine what he would have envied me for.”

Unsure of how to respond to that, Muichiro decided to change the subject. “…So what happened, then? In the end?”

“You saw it yourself. I became a demon to survive. And Yoriichi grew old… as all humans do.”

“Did you… did you kill him?” Muichiro asked, almost afraid to know the answer.

“…No, I did not. We confronted each other, but… it was not even a battle. He could have killed me in one strike. But instead he spared me a fatal blow… and died of old age, standing with his sword drawn. In the end… after everything I did to live on… I never surpassed him.”

Yoriichi died of old age? So Kokushibo didn’t kill his brother; Yoriichi’s sudden death had spared them both that pain. But was it really a coincidence? “Why do you think he didn’t kill you?”

“I do not know. I imagine… he pitied me, and what I had become.”

Kokushibo seemed certain of his words. But Muichiro remembered the vision of Yoriichi, and the tears running down his face. That immeasurable sadness… he couldn’t believe that it was just pity. “I don’t think so. I think you were his brother, and even after everything, he still loved you. I think he couldn’t bring himself to hurt you.”

Kokushibo’s eyes widened; he seemed to consider his words for a moment. Then they narrowed again, face creasing in irritation, and he turned away. “There is… no point in discussing this any further. The past is long since gone. I cannot ask him anything… nor can I reconcile with him.”

“But maybe you can look back on your memories of him with a new perspective!” Muichiro continued to press the subject. For some reason, this felt important to him. Maybe it was because he was a twin himself, but the idea of resenting one’s own twin for centuries was too sad for words. “That’s what happened with me and Nii-san. He used to be cold and cruel, and I thought he hated me. But that wasn’t true! He just wanted to keep me safe, but he was in pain and couldn’t show it properly. Maybe-”

“Enough,” Kokushibo interrupted him in a stern but resigned voice. “There is no use in reflecting on the past… not for me. I chose my path long ago. I cannot change it now.”

Muichiro fell silent, and for a while he just stared at his teacher, searching his face for any sign of what he was feeling. The Upper Moon’s expression was carefully crafted, but Muichiro could see the slight creases of his eyes and the tightness of his lips holding back a scowl. He looked upset.

Muichiro looked down, and noticed Kokushibo’s hand resting on the floor. Slowly, carefully, he moved his own hand, until his fingers brushed over the older demon’s claws.

Kokushibo jolted upright, eyes darting to Muichiro in confusion. “What are you doing?”

“Nii-san always holds my hand like this whenever I’m sad. It’s to let me know I’m not alone, and that everything will be okay,” Muichiro explained, smiling at the thought of his brother. “So I thought…”

He trailed off, suddenly realizing how strange his gesture really was. Kokushibo was not his brother or even his friend. He was his teacher, his mentor. And though he often found himself forgetting it, he was also his enemy. And here he was trying to hold his hand.

Muichiro pulled away, his face going red. “I-I’m sorry, I shouldn’t have-”

“No, it’s fine. I do not mind,” Kokushibo’s words shocked him into silence. “I was simply… surprised. My apologies.”

Muichiro grunted; Kokushibo was apologizing a lot to him lately. But he took that as an invitation to lean in close to the Upper Moon. His kimono was a lot softer and more comfortable to rest his head on than the pillar, anyway. Kokushibo stiffened, but he soon relaxed and allowed him to stay there.

Muichiro breathed in Kokushibo’s scent, the only smell here that didn’t set him on edge. He wasn’t adept at sniffing out people’s emotions the way Tanjiro was, but he thought he could pick out the scent of sadness.

“Teacher?”

“Hm?”

“What you said before, about it being too late to change your path?” Kokushibo hummed again, and Muichiro continued. “Well, I don’t think that. You’re your own person, and you can choose to be better. As long as you’re alive, you can still change.”

Kokushibo didn’t respond to that. But Muichiro could tell that he was thinking. About what, he didn’t know, but he hoped something he said had gotten through. Muzan’s blood itched painfully under his skin, and Muichiro shuddered and leaned further into Kokushibo’s kimono to try and ignore it.

“Lord Kokushibo! Muichiro! There you are!”

The cheerful voice sent shivers down Muichiro’s spine. His claws clung to Kokushibo’s kimono as he looked up at a blonde-haired demon whose eyes shone with the colors of the rainbow. Despite their beauty, the mere presence of this demon unnerved him. He smelled strongly of blood, but not of bloodlust; in fact, he couldn’t sense his intentions at all.

“Douma…” Kokushibo growled lowly, “Leave us be… Your presence is not welcome here.”

“Lord Kokushibo, I’m hurt!” Douma, Upper Moon Two, gasped. But despite his words, he kept smiling. “I’ve no intention to cause trouble; I only wanted to give Muichiro a little gift!”

A gift? Muichiro didn’t want anything to do with whatever Douma would consider a gift. It was then that he noticed a strange smell coming from the rainbow-eyed demon. He was carrying something wrapped in cloth. The smell was familiar; his stomach dropped.

Please, no!

“A gift…?” Kokushibo echoed. He sniffed the air, and his eyes narrowed.

“That’s right!” Douma placed the cloth on the floor and let it unfurl. Immediately, Muichiro covered his mouth and nose as the smell of Marechi blood hit him full force. A mutilated human torso laid before him, its head and limbs missing, its blood still fresh. From its size alone, he knew it was a child. His stomach growled, tempted by the prospect of meat after being starved for so long, and he felt bile rise in his throat.

“I searched long and hard for a human of high enough quality to please Lord Kokushibo’s descendant, until I stumbled across this one with Marechi blood!” Douma continued, oblivious to - or perhaps purposely ignoring - his distress. “It’s a shame he was a boy; a girl would have been more nutritious. But beggars can’t be choosers, right?”

Muichiro shuddered and turned his head away from the gruesome sight, only for a clawed hand to suddenly grab his chin and force him to look into Douma’s eyes. The kanji for ‘Upper Two’ bored into him, reminding him of the power this demon held.

“Now, now, it’s rude to refuse a gift, you know! You haven’t eaten in a long time, right? You must be starving! So go on, eat!”

It happened too quickly for Muichiro to process. He spotted a chunk of bloodied meat in Douma’s other hand, but before he could think about it, his hands were ripped away from his face. The scent of Marechi made him gasp, and in that moment the piece of meat was forced into his mouth.

Immediately, an overwhelming flavor assaulted his senses. It was like nothing he’d tasted before; the flesh and blood of demons didn’t even compare. It was incredible. It was horrible. He tried to spit it out, but Douma held his jaw shut.

“Ah, ah, no spitting it out! At least give it a chance first! You might like it!”

Muichiro’s mind was screaming that he would not, but his traitorous body wouldn’t listen to him. Every instinct cried out for him to swallow and satisfy the aching hunger. The marechi blood on his tongue made his head spin, his vision blurring. His thoughts were a panicked, desperate stream fighting to stay in control.

Get it out! Get it out get it out get it out!

Douma grinned and-

-a sword sliced through the Upper Two’s neck, parting his head and sending it rolling across the ground. His hand let go of Muichiro’s face, and he thought he must have blacked out, because suddenly he was gasping and heaving over a bloody mess on the floor. The unidentifiable piece of meat laid in a pool of blood, along with something-

Muichiro wretched, blood pouring from his mouth. Oh, that was his tongue. He held up his bloodied claws, bits of tissue clinging to them. He stared numbly, before slowly lifting his gaze to see Kokushibo standing in front of him, his sword returning to its sheathe.

“Know your place… Upper Moon Two,” Kokushibo growled, his six eyes glowering, an unmistakable fury in his voice. “If you touch him again… I will make you regret it…”

“Come now, Lord Kokushibo, I was only trying to help!” Douma said, his body casually reaching for his head and placing it back on his neck. “Can’t you see how much he’s suffering by denying his true nature? Even you must feel pity for him, surely?”

Slowly, Muichiro became able to feel again, and what he felt was hunger and revulsion. The taste and smell of the marechi still lingered as his tongue regenerated. His stomach howled, furious at being denied, and Muichiro felt hot tears forming in his eyes, a sob escaping him along with another splatter of blood.

This was awful; he was awful. A child was murdered, his corpse tossed in front of Muichiro like meat to a dog, and all his body wanted was to devour as much of it as he could. He hated this. He hated himself.

“Oh look, he’s crying,” Douma observed, his tone full of fake concern. “Poor Muichiro, you’d be so much happier if you’d just accept what you are! There’s no Heaven or Hell, so it doesn’t matter how virtuous or wicked you are in this life. Your insistence on not eating humans to preserve something as nebulous as humanity is completely pointless!”

Muichiro shook his head, refusing to listen. No, Heaven and Hell were real, and his humanity did matter… didn’t it? But the smell of flesh and blood was still there, enticing his hunger, reminding him that he was not human. He was still a demon, a monster. Maybe Douma was right about one thing; no matter how good he tried to be, he was going to the same place in the end.

“Enough, Douma,” Kokushibo said again, leaving no room for arguing. “Leave us...”

“As you wish, Lord Kokushibo!” Douma bowed. “And you can keep my gift to Muichiro! Maybe he’ll change his mind!”

Muichiro shuddered, his empty stomach turning and a feeling of nausea rising in his throat. He’d never met a demon so utterly devoid of any humanity. He hated the Upper Moon Two almost as much as he hated Muzan himself.

As Douma walked away, humming merrily to himself, Kokushibo helped Muichiro to his feet. The young demon was too tired to refuse his help. The fog in his mind struggled to bury the memory of the Marechi’s taste in his mouth, Muzan’s blood burning painfully and pushing it back. He didn’t notice Kokushibo’s subdued, almost guilty expression.

“That is… enough for today. Let us… go back to your room.”

His room. His dark, empty, lonely room. Muichiro sobbed and clung to Kokushibo like he was his lifeline in a stormy and uncaring sea. “I want to go home…”

“I know,” was all Kokushibo said as he picked him up and carried him away, until the nauseating, intoxicating smell of the Marechi no longer reached him.

—

Kokushibo brought Muichiro back to his room, laying him down on his futon and covering him with Yuichiro’s haori before closing the door behind him. But Muichiro couldn’t fall asleep, no matter how much he wanted to. Alone in the darkness again, he sat up and moved to rest against the wall.

A shudder ran through him; the pain and hunger were unbearable, a gnawing void eating him from the inside out. Traces of the Marechi still lingered beneath the layers of his own blood filling his mouth; the fog in his head buried most of that horrible experience, but he still remembered the taste, awful and wonderful in equal measure. It made him sick all over again.

How long was this going to go on? Was it only going to get worse? Muichiro couldn’t imagine how it could, but he was sure Muzan would find a way. Yuichiro’s haori still laid on the futon, and he reached out to grab it and pull it towards him. Sliding it on, he could close his eyes and almost pretend Yuichiro was there with him. The mere thought almost brought him to tears.

I’m sorry, Yui. I’m trying to be strong, but… I just want to see you again!

He needed to see him again. Muichiro opened his eyes and held out his hands, and white mist rose up around him. The mist flowed forward, gathering in front of him and collecting into a familiar shape. A human shape, long hair and flowing clothes, and its face…

…its face was nothing, just a blank swirl of mist. His hands shook, and the mist shook with them, quickly falling apart. Muichiro clenched his teeth and forced his hands to hold still, solidifying the mist again into its prior shape. He tried to picture his big brother’s face, those sharp but warm teal eyes, his kind smile whenever he looked upon him. The double’s face shifted, two holes where the eyes would be becoming distinct, a facsimile of a nose and mouth forming. It was…

It wasn’t good enough. It didn’t look like Yuichiro.

He tried again, but his hands were trembling. Tears obscured his vision. The mist shook and the face distorted, becoming unrecognizable. No matter how he tried, it wouldn’t match the image in his head. It was just a crude copy, a failed recreation, a mockery-

Muichiro screamed and buried his face in his hands. The misty double collapsed into a cloud that hung aimlessly around him. Why couldn’t he do it? Failure, failure. Time blurred as he sobbed into the darkness of his room.

Until he felt something approach. A familiar presence. Muichiro looked up, and through the mist and his tears he saw the shadow of himself, six turquoise eyes glowing within the darkness.

“You…!” Muichiro hissed, instantly on guard. “What do you want?”

For a moment, the shadow said nothing. It just continued to stare down at him with an unreadable expression. And then he heard its voice.

He won’t come for you.

There was no cruelty or triumph in its tone. Only a somber statement of fact. But Muichiro refused to believe that. He curled in on himself and looked at his feet, avoiding the shadow’s gaze.

“He will. He… he won’t give up on me.”

It is not a matter of choice. Understand your position. You are in a place cut off from the world you know, a place humans cannot enter. He can search and search and search, but he will never find you here.

Muichiro couldn’t respond. The shadow stepped closer, and he closed his eyes, bracing himself. But nothing happened, and slowly he opened them again to see his dark double knelt down before him. Their eyes met, and he didn’t see the usual hostility present within its gaze.

You are running out of time. Muzan grows more impatient by the day, and soon he will tire of your resistance. What then? Even if your brother were to find you, it would be too late. There would be nothing left of you to save.

Muichiro recognized the implications of those words. Nothing left to save. Either he would be killed, or he would be made into a mindless beast like all the other demons. He shuddered at the thought of Yuichiro seeing him like that. Assuming… assuming he would ever find him at all…

Do you understand? Your brother cannot reach you. He cannot protect you. He cannot save you. The only one who can… is you.

The shadow’s voice was soft and absolute. There was no arguing with it; Muichiro knew it was right. What he had been denying all this time was the truth. Yuichiro wasn’t coming to save him. No one was. The only one he could rely on was himself.

But how could he save himself? He was only alive by Kokushibo’s good graces. He couldn’t defeat the Upper Moons, let alone Muzan himself. He couldn’t escape the castle. He couldn’t do anything. Even with all the power he possessed as a demon, he had never been as powerless as he was now.

“I… I can’t…” Muichiro felt his tears and sobs start anew. “I can’t keep doing this… not without him! I need him! I need to see him again!”

That was all he wanted. He just wanted to see Yuichiro again, to feel his touch and hear his voice tell him that everything would be okay. He cried, no longer caring if the shadow was there to see him or not. It didn’t matter, anyway. What good was his pride in the face of something that only existed in his mind? Even the shadow wasn’t real; he was truly alone.

A hand touched his own. Muichiro jolted upright, his eyes darting to a shadowy claw holding onto his left hand. The touch was warm, too warm, but he was too stunned to pull away. He looked up, and the shadow met his gaze.

Everything will be okay.

"Huh?" He didn’t understand. It almost sounded like…

And then, right before his eyes, the shadow began to change. Bit by bit, the darkness fell away, revealing what was underneath. Pale skin, black hair tipped in turquoise, and a dark mist-patterned haori; Muichiro’s eyes went wide, a gasp escaping him.

“Yui…?” No, of course this wasn’t Yuichiro. It was still the shadow. But, why was it… why take this form?

The Yuichiro lookalike opened two teal colored eyes, slit pupils looking back before expanding into warm circles. He smiled kindly, a perfect match to the vision in Muichiro’s memory.

“What are… what are you doing?” Muichiro asked, voice barely above a whisper.

“I am that which protects you,” the double spoke in Yuichiro’s voice. “Everything I do is for your survival, to make you stronger so that none may harm you. Because that’s how a big brother should be, right?”

“You’re… you’re not Yuichiro…” Muichiro could barely get the words out. His mind struggled to process what was happening.

“No, but I will protect you in his stead. I will be whatever you need me to be.”

It was then that the reality before him started to set in; somehow, someway, he was seeing his big brother and hearing his voice. But, it wasn’t Yuichiro. It was the shadow, the thing inside him that tempted him to give into his demonic nature. What was it planning? What was it trying to accomplish by taking Yuichiro’s form?

“N-no… No!” Muichiro’s voice rose into a shout. “I don’t believe that! Even if you look like him, there’s no way I can trust you! You’re just trying to trick me!”

The Not-Yuichiro shrugged, uncaring of his anger. “Believe whatever you want. But whether you trust me or not, I’m the only one here who's truly on your side.”

The fake was hard to look at; Muichiro turned his gaze away. “…Teacher-”

“Can’t be trusted. How can you trust the man who kidnapped you? Who stood by and let you choke on Marechi blood? Any familial love he feels for you will always come second to his loyalty to his master. All you can rely on here is your own power.”

Muichiro flinched; this fake sounded like the old Yuichiro, harsh and coldly logical. But he knew he was right. He couldn’t trust Kokushibo, no matter how he felt about him. He couldn’t trust anyone here.

He shuddered, once again feeling on the verge of tears. Not-Yuichiro squeezed his hand, startling Muichiro, but for some reason, he didn’t pull away.

“But don’t be scared. You’re not alone. I’m here.” The fake’s lips turned up in a smile. “Everything will be okay.”

Muichiro felt like he was going to be sick. It was mocking him; this thing his mind created was mocking him. But still his heart ached. Those words, spoken by his twin, were what he wanted to hear most of all.

Not-Yuichiro spoke again after a pause. “You’re exhausted. You should get some rest while you can.”

Muichiro doubted he would; sleep was all but impossible with the agonizing fire constantly running through his veins. But something in that voice made him want to try. He laid his head against the wall, and despite everything, his weary mind soon drifted off into slumber, lulled by the sound of his big brother’s voice and the too-hot warmth of his hand.

“Go to sleep now. And don’t worry. I’ll protect you, from all who would hurt you, and all who would hold you back.”

—

A sea of mist stretched out without end. Muichiro had been here before, many times. It wasn’t real; it was nothing but a dream. He sat on the ground and curled in on himself. There was no point in searching for anyone in the fog. He was alone here. Always alone.

Before he knew it, tears were coming to his eyes. A sob escaped him, but he didn’t try to stop it. Alone in the mist, there was no one to see him cry.

Until he heard something. A faint voice, deep inside the mist, but slowly growing closer and louder.

“Yui…?” he whispered. That was his twin’s voice; was he here? But this was just a dream, right? Yuichiro couldn’t be here…

No... No, it wasn’t him! It was just that damned shadow trying to trick him again!

“Go away!”

The mist turned red, responding to his anger. How dare that imposter use his brother’s voice against him?! Even in his dreams, he couldn’t escape it! The blood mist roared, screaming out his rage, his pain, his despair, until the voice was gone, and all was silent again.

Until he was all alone again.

Chapter Text

Yuichiro waited until night had settled before making his leave from the estate. It was late, and he had made sure Aoi was asleep and wouldn’t get in his way. Under the cover of darkness, lit only by the moon high in the sky, Yuichiro secured the bag held over his shoulder and prepared to depart.

“And where do you think you’re going, brat?”

Yuichiro startled, but as he recognized the voice, his irritation returned. “Of, you’ve got to be kidding me…”

“Hey, if it were up to me, I wouldn’t be here either,” Sanemi said as he leapt down from the roof to land in front of Yuichiro. He looked down on him and grinned wryly. “Man, you look like shit, Tokito. When’s the last time you slept?”

Yuichiro ignored his remark. “Why are you here? You’re the one person who's never come by, so why show up now?”

“Because your little butterfly friend is worried you’ll do something stupid after the fight you had. And lucky me, my estate is the closest one to yours, so she asked me to help,” Sanemi rolled his eyes. “Now, are you going to tell me where you’re going or not?”

Really? Aoi went to Shinazugawa for help? But even if Sanemi was here to help, Yuichiro was not in the mood for his bullshit. “What does it look like? I’m going on patrol.”

“Really now? That bag looks a little heavy for one night on patrol,” Sanemi grinned, easily seeing through his lie.

Yuichiro scowled and looked away. “Why do you even care?”

Sanemi sighed and looked irritated again. “Seriously? I may not like you, Tokito, but that doesn’t mean I can’t see how much you’ve been falling apart since your brother was kidnapped. So I’ll ask you one more time, and if you don’t answer, I’m dragging you inside and tying you to your bed. Where are you going?”

There was no room for argument in Sanemi’s tone. Yuichiro scowled further and decided to come clean. “I'm going after Kokushibo.”

“Kokushibo? You mean Upper Moon One?” Yuichiro nodded, and Sanemi groaned. “You can’t be serious... Do you have a death wish, Tokito? How are you even going to find him in the first place?”

Yuichiro had an answer to that. “I’m going back to our old home. He appeared there once; I’m certain that if I go back, he’ll appear there again.”

It was the only thing he could do. He couldn’t blindly wander the country at night and hope he’d just cross paths with the demon. He needed to go somewhere they both knew, someplace with significance to them both. If he did that, he was sure that Kokushibo would show himself.

“So that explains the bag,” Sanemi said, his expression growing serious. “But you’re crazy if you think I’m just going to let you waltz right into the hands of one of our strongest enemies.”

“He won’t hurt me. If he wanted to capture or kill me, then I wouldn’t be here right now.”

“You don’t know that. You can’t trust an Upper Moon; if you could, then Muichiro would be here right now.”

Yuichiro clenched his teeth, having no retort to that. He knew Sanemi was right; he still didn’t know why Kokushibo chose to retreat with only Muichiro when he could have easily killed Tanjiro and Genya and taken him, too. Kokushibo wouldn’t kill him, but seeking him out could still end badly.

But he didn’t care. He needed to find his little brother. “You don’t get it. I know it’s dangerous. But I need to get to Muichiro.”

“And it’s fine if that means ending up a prisoner right alongside him?” Sanemi asked.

No, his rational mind said, but his heart said something else. “Yes, it is! At least we’d be together, then!”

“Yeesh, this again…” Sanemi rolled his eyes. “Tokito, I’m going be honest with you: you and your brother are codependent as fuck. I’m surprised you both don’t burst into flames when you’re more than eight feet away from each other.”

Yuichiro reeled back like he’d been punched. For a moment, his mind came to a halt, struggling to process what he’d just heard. “Co… codependent?! We’re not codependent! We’re twins! We support each other!”

“Sure, until something like this happens and you completely lose your shit.”

“What are you even saying?! Muichiro’s been kidnapped! Of course I’m upset!”

“I’m not talking about that. I’m talking about how irrational you’re being. You think Muichiro would want you to be wherever he is right now? You think he would want to be together if that meant you being at the mercy of whatever Muzan wants? If you’d quit being a self-destructive idiot and think for once, you’d realize that.”

“I can’t-”

“And spare me that crap about it being "not right" for you to be happy while your brother’s not. It’s because he’s suffering that he’d want you to be happy in his stead.”

“Oh, shut up!” Yuichiro snapped. “What do you know, anyway? Trying to tell me how I should feel about my little brother when you left yours behind! What if it was Genya in Muichiro’s place, huh? Would you even care?!”

Sanemi scowled; the subject of Genya was clearly a sore spot for him. “Tch… of course I’d care. Listen, Tokito, I’m not gonna claim I wouldn’t act the way you are now if I was in your shoes. But I’m not.”

“So you’re acknowledging that you’re a hypocrite? Good, glad we can agree that I have no reason to listen to you, then.” Yuichiro tried to walk past Sanemi, only for the latter to hold out an arm and shove him back. “What do you think you’re doing?”

Sanemi heaved a sigh. Then he stepped back and placed a hand on the hilt of his sword. “Fine, talking’s never been my strong suit, anyway. Fight me. If you win, I’ll let you leave. If you don’t, then you’re staying right here.”

Yuichiro grit his teeth. He could feel a headache building again, but he refused to back down. He drew his own sword and composed himself. “If that’s what it takes to get you out of my way, then fine.”

His track record against Sanemi wasn’t great; the older Hashira had a level of experience he couldn’t match. But this was for Muichiro’s sake. Sanemi drew his sword and waited. After a tense moment of silence, Yuichiro made the first move. He lunged forward, swinging his sword, but Sanemi blocked it with ease. Their swords locked together for a moment before Sanemi pushed forward to throw him off balance. Yuichiro saw this coming and jumped back, but he still stumbled for a second as he landed.

Sanemi scoffed, all humor gone from his voice. “Tch, look at you. Have you been taking care of yourself at all, Tokito?”

Yuichiro didn’t answer that. He knew that Sanemi was bigger and stronger than him and he wouldn’t win in a direct clash. He could only ever get the upper hand in their spars by using his greater speed and evasiveness. But as he tried to feint and get into Sanemi’s blind spots, the Wind Hashira was able to react to all of his strikes. His movements were slower than they should have been, his body not moving the way he needed it to.

He feinted a strike up high, and when Sanemi moved to block it, Yuichiro dropped low, his blade swinging at his feet. Sanemi grunted, but then he jumped and landed on the blade of Yuichiro’s sword. His momentum thrown off, the Mist Hashira lost his balance and fell face-first on the ground.

Sanemi crouched down, still pinning his blade beneath his feet. “Give up, Tokito. You aren’t beating me like this.”

“I… I’m not finished…!” Yuichiro tried to get up and pull his sword away, but he couldn’t manage it.

“Yes, you are. Your body’s running on empty. I bet you’ve been training all this time without any regard for your health, right? Trust me, I know what that looks like. I’ve been there.”

Yuichiro’s eyes narrowed. “So… so what if I have?! The training’s the only thing that gets him off my mind! When I’m not doing that, I can’t stop thinking about him; alone, afraid! He needs me! I need him!”

His entire life revolved around Muichiro. For the past three years - no, even longer than that, ever since their parents' deaths - everything he did was for his little brother’s sake. And now that he was gone, it felt like a part of his soul had been torn away.

“You’re just proving my point, you know,” Sanemi growled.

“Shut up!” Something in Yuichiro snapped. A surge of desperate strength filled him, and he elbowed the unprepared Sanemi in his stomach before tackling him to the ground. The Wind Hashira’s grip on his own sword loosened, and Yuichiro wrestled it from his hand to hold it against his throat. “What point?! Am I just supposed to stop caring about him?!”

“No, of course not! What you need to do is stop acting like you’re alone in this fight!” Sanemi yelled, heedless of his own blade against his neck. “You’ve got friends, Tokito; there are people here who care about you! Let them help you!”

“I don’t need help!”

“Then do it!” Sanemi’s fingers gripped the steel of his green blade and brought it closer against his neck. “Take that sword and kill me, because the only way I’m letting you walk out of here the way you are now is if I’m dead!”

Yuichiro froze, the raging fire driving him extinguished in an instant. An icy chill crept up as he became aware of the position he was in. He was on top of Sanemi, sword held to his neck, and the Wind Hashira was giving him a choice. Would he even resist if Yuichiro chose to run that blade through his throat? His grip on the hilt trembled.

How did it come to this? He just… wanted to be with Muichiro again. Was he really willing to kill his own companions to make that happen? Was that the kind of person he was?

Muichiro wouldn’t want this.

The fight left him. Shame flooded in, and Yuichiro squeezed his eyes shut, feeling tears behind them. The sword in his hands was gently pulled away, and he felt Sanemi easing him off his body. He didn’t try to fight it.

Yuichiro realized that his love and worry for Muichiro had warped somewhere along the way. Subconsciously, he must have believed no one cared but him, so he pushed everyone away. He went back to being that hurt child that was angry at the whole world. Muichiro’s heart would break if he could see him now.

He heard Shinazugawa’s voice. “Come on, Tokito. Take my hand.”

Yuichiro opened his eyes, seeing Sanemi crouched before him, a hand held out in offering. He could only stare in disbelief. Sanemi had never done this before, not even in the previous spars that he’d lost. But more than that, the look in Sanemi’s eyes was different. He was… truly worried. The animosity and rivalry they had maintained for years didn’t matter right now. He was putting that all aside to try and help Yuichiro.

How messed up was he that even Sanemi Shinazugawa, of all people, could see it?

Without the anger pushing him forward, he became truly aware of how tired he was. Yuichiro reached out for Sanemi’s hand, and the Wind Hashira pulled him to his feet. Upon standing, his legs almost fell out from under him again, but Sanemi’s arm caught him just in time.

“Yeesh, you really are running on empty, aren’t you?”

Yuichiro looked dejectedly at the ground. “…I’m sorry.”

“Don’t be. You’re not the first person to point a sword at my neck, and you won’t be the last.” Sanemi grinned at his joke, but when Yuichiro didn’t react, he sighed. “Look, you’re only human. Like it or not, you can only do so much on your own. That’s why the Corps exists, because humans need to work together if we want to win this war.”

Yuichiro gasped as a memory came to his mind, spurred by Sanemi’s words. The Master’s voice resounded in his head.

“Needing help is not a sign that you are weak. We humans can accomplish such greater things when we work together.”

That was years ago, before he even became a Hashira. Why was… no, he knew why he was remembering it now. Because the Master’s words were the truth he’d been denying.

“I can’t save Muichiro on my own,” he finally admitted. “I need... I need help.”

Sanemi looked surprised; perhaps he hadn't truly expected him to ever say it. But then he smiled, a chuckle on his lips. “Took you long enough.”

Yuichiro felt his irritation return. “Shut up, old man.” He didn’t have the energy for much more than that; he could feel himself swaying on his feet.

“Maybe I should’ve let you run off and die, you shitty little-” Yuichiro almost collapsed again, and Sanemi barely caught him. “...Well, too late for that, I guess. Come on, let’s get you to bed.”

It spoke to how exhausted Yuichiro was that he didn’t protest as Sanemi hoisted him up onto his back and carried him inside the Mist Estate. As they walked, Yuichiro struggled to stay awake, but at the same time, his mind was whirling with thoughts and anxieties that kept him from falling asleep.

“Hey, Shinazugawa…?”

“Yeah?”

“Be honest with me… do you… do you think we’ll find Muichiro?”

Sanemi was silent for a while, thinking over the question. Then finally, he answered. “…I know you don’t want to hear this, but Iguro’s probably right that Muzan wants to turn Muichiro against us. So, when Muzan shows himself again, that’s probably when we’ll see your brother, too.”

“But what if it’s too late by then?” Yuichiro’s voice was small, dreading to even say it out loud. But his implication was clear.

Another long pause. And then, “If worse comes to worse, I’ll fight him for you. I won’t make you go through that.”

Yuichiro suddenly remembered that Shinazugawa had gone through something similar. A family member turned demon, who had to be killed. That he would offer to spare Yuichiro from that pain; an indescribable feeling welled up inside him.

But…

“…No, if that happens, it has to be me. It can’t be anyone else.”

Yuichiro wouldn’t let anyone else fight his battles. If the worst came to pass, if he had to fight his twin… then it would be his blade, and his alone, that would end his brother’s torment.

“…Alright,” was Sanemi’s only response. He took him back to their room, and Yuichiro felt himself being laid on his futon. He was already drifting off; he wondered if he’d have that dream again, with the sea of mist and that strange shadow.

But Sanemi stayed by his side that night, and his sleep was long and dreamless, a restful reprieve from his waking nightmare.

—

Muichiro was returned to his room after another session with Muzan. The torture had been shorter, but no less painful; it was clear that the shadow was right, and Muzan was losing patience with him. And speaking of the shadow…

“Welcome back.”

Muichiro lifted his head to glare at the fake wearing his brother’s face. The Not-Yuichiro smiled down at him, mocking him with his false warmth.

“Go away. I don’t want to see you,” Muichiro growled and looked away, focusing on healing his wounds.

“Is that any way to talk to your big brother?”

“Shut up. You’re not even good at being Yui. You smile too much, and Yui doesn’t have his haori right now because I have it.”

“That’s true, and you’ve done such a good job of taking care of it, haven’t you?”

Muichiro glared and retrieved the haori from under his futon. “Yes, I have.” He wrapped it around himself as if to prove a point. It was the only piece of his twin he still had; of course he took good care of it.

Their “conversation” was interrupted by a knock outside the door. Kokushibo opened the door, and Muichiro turned his gaze to the floor. He remembered what the shadow had said, the bitter truth about his teacher.

“Come… You will accompany me.”

Muichiro nodded and followed wordlessly. But they didn’t go far before the Upper One stopped. “Nakime.”

The sound of a biwa answered him, and suddenly they were on top of a large platform. Nakime sat by the edge, strumming her instrument.

“What is your request, Lord Kokushibo?” she asked in a tone that sounded utterly disinterested.

“I request an audience with our lord.”

“For what purpose?”

“That is none of your concern.”

Nakime hummed, accepting that answer; most likely, she didn’t care either way. After a long moment of silence, she nodded. “Lord Muzan will see you now.”

Kokushibo turned to Muichiro. “Wait here… I will return soon.”

Muichiro nodded, not saying a word and still avoiding eye contact. Kokushibo watched him silently for a moment, then turned back to Nakime.

She strummed her biwa and Kokushibo vanished. It was just Muichiro and Nakime now, who went back to plucking the strings of her instrument in a simple but skillful melody. It was nice to listen to, but it didn't distract from the constant aching pain, nor the feeling of Not-Yuichiro staring at him from the corner of the platform. Muichiro fiddled with his claws and turned to his only other company here.

“Miss Nakime?”

The demon in question ceased her strumming and inclined her head to show she was listening.

“Can you brush my hair?”

—

The biwa’s echo brought Kokushibo to Muzan’s study, where he dropped into a bow. The Demon King’s back was turned, but he was well aware of his presence.

“It’s rare to see you come to me of your own volition.” Muzan’s displeasure was apparent from the first word. “I don’t recall sending you on any missions recently. To what do I owe the pleasure of this visit?”

Kokushibo said nothing; internally, he braced himself. Muzan turned to face him, red eyes piercing deep into his being. “Have you come to speak about your student, Kokushibo?”

The Upper Moon lowered his head. “That is correct, my lord.”

Muzan smirked knowingly. “You think I’m being too harsh on the boy. But clearly I’m not being harsh enough, given that he remains firmly loyal to the demon slayers.”

“The boy possesses a strong will… pain will not break him.”

Muzan hummed and placed a hand to his chin, considering his words.

“With all respect, my lord… allow me to take him fully under my wing. There is no need for this torture… I will get through to him.”

“Will you now?” Muzan lowered his hand, his glare returning. “I’ve given you many opportunities to have the boy and his brother for your own, and yet you’ve found a way to squander each and every one of them. Your bias towards your two descendants is quite clear to me.”

“My lord, this torture will not yield the results you wish for,” Kokushibo tried to reason with his master, ignoring the barb against him. “Muichiro is becoming unstable. His mind will break before his will does.”

He would have to be blind to not have noticed the change in Muichiro. How on edge he seemed, even more than before. How his eyes shifted to glance at empty air, and how he avoided looking at or speaking to Kokushibo for too long. And he heard him too, talking to something as if holding a conversation, even though he was the only one in the room.

Something had changed after Douma tried to force that Marechi blood onto him, something that greatly concerned the Upper Moon One. He still remembered their talk, how Muichiro had let him open up about Yoriichi, and tried to soothe his feelings of envy and inferiority. Muichiro had seen something in him worth helping. And now that same child was withdrawing into himself, the distance between them growing further and further.

“Muichiro…? That’s the first time you’ve used his name around me.” Muzan blinked, looking almost surprised. Then his eyes narrowed. “You’ve changed, Kokushibo.”

His tone was full of disappointment. Kokushibo froze, a strange feeling of dread running through him. “I don’t understand…”

“You can lie to yourself, but you cannot lie to me. You care about the boy, don’t you? As more than just a student. You’ve come to think of him as family, as a son, even.”

On instinct, Kokushibo tried to refuse the idea. “No, that is not-” the Upper Moon was cut off by a sharp pain lancing through his entire body. He almost collapsed from his bowed position, his cells heating up and breaking down, cracks forming along his skin.

“Not what, Kokushibo?” Muzan’s tone dared him to try and talk back, to give even more reason to punish him. “I am never wrong, remember that. You’ve allowed your lingering human affections to cloud your judgment. Well no more.”

Muzan stepped forward, looming over his subordinate. Kokushibo couldn’t even move to look up at him. “I will use that child’s power to destroy the demon slayers. His mental state is of no importance; I don’t need him sane to be a weapon.”

A distant rumbling echoed around them, and suddenly the pain paralyzing Kokushibo stopped. He fought to maintain his composure as he looked up at his king.

Muzan looked up as well, then tilted his head to glare down at the Upper One. “It seems your descendant has caused some sort of commotion.”

Kokushibo’s dread only grew.

Muichiro, what have you done?

—

Muichiro sat silently as Nakime ran a brush through his hair. The rhythm was soothing, and he kept his eyes glued to the floor. But he could still feel Not-Yuichiro’s gaze upon him. Desperate to distract himself, he spoke up.

“Miss Nakime?”

“Yes, child?”

“Why do you follow Muzan?”

“Why ask such a thing?”

Muichiro shrugged. “I’m just curious.”

The demon seemed to think for a moment before answering. “I have a certain set of abilities that make me very valuable to Lord Muzan. It is in my best interest to obey him.”

“Are you talking about this castle?”

“Indeed. The Infinity Castle is made by my Blood Demon Art; I am needed to maintain it. In return, Lord Muzan gives me safety and greater power.”

Muichiro looked back out at the seemingly endless expanse of space within the castle. “How is that possible, though? For a place like this to exist, even with a demon’s power?”

“It simply is.” Nakime didn’t elaborate. Perhaps even she didn’t know. In the ensuing silence, Muichiro thought about what to say next.

“This is your chance to escape.”

“Huh?” Muichiro said aloud, eyes turning towards Not-Yuichiro, who eyed Nakime with a calculating gaze.

“What was that, dear?” Nakime asked, pausing in her brushing.

“Oh, uh, nothing, I thought I heard something…” He looked back towards the shadow, thinking instead of speaking. What are you talking about?

“Use your senses. This demon is powerful, but her power lies in being able to control this space; she herself is vulnerable. One decisive strike could kill her and cause this entire reality to fall apart. You would have a chance to escape this castle as it collapses.”

Muichiro’s eyes went wide, astonished by the idea. It made sense; Muzan couldn’t control this space without Nakime. If she were to die and the castle were to collapse, he could likely lose the Demon King and his Upper Moons in the resulting chaos. He could get outside, and Muzan would lose his stronghold, exposing him to the demon slayers.

There was just one issue. He didn’t know what time it was outside the castle. But, what if it’s daytime?

“That doesn’t matter. You have your brother’s haori, don’t you? It’ll keep you safe.”

Muichiro nodded. That was something he could worry about later, anyway; the most important part was getting out of the castle and back outside in the first place. “Um, Miss Nakime?”

Nakime breathed a sigh. Evidently, she wasn’t much for conversation. “Yes, dear?”

“Have you ever considered not following Muzan?”

Nakime paused, then let out a chuckle. “Now why would I consider something like that?”

“Well, you’re your own person. You have all this power, but you have to stay here to maintain the castle, right? Don’t you want to do what you want for once?” He was mostly asking to get her guard down, but now he was genuinely curious about her answer.

Nakime chuckled again. “Hmph, that’s where you’re wrong. I am not my own person; no demon is. We are all extensions of Lord Muzan’s will. Whatever we want must come second to his desires.”

“That’s so sad, though…” Muichiro frowned. He had broken free of Muzan’s curse long ago, though he had no idea how. But most other demons were still shackled to the Demon King’s will, unable to act or even think freely without him knowing. When he thought about it like that, he almost pitied them.

“Perhaps, but I am quite content in my position. It affords me greater privileges than most, and it is not so different from how I lived as a human.”

“What do you mean?”

Nakime grinned. “I killed people as a human, too. Greedy, unfaithful men who wanted a night of passion, if you understand my meaning.”

Muichiro… did not. But that didn’t matter right now. “You killed people when you were human? Why?”

“You’re still a child, so I don’t expect you to understand. But there are many men in this world who are little more than parasites, who take all they can and give nothing in return. The blood of those worthless men sharpens my focus and makes my music more beautiful. They are worth more dead than they ever were alive.”

“That’s so cruel…”

“The cruelest humans make the cruelest demons. And the cruelest demons are the most powerful. That is how our world works.”

“Why should it have to be that way, though? Why bring more suffering into the world?” Muichiro couldn’t understand; the world was unfair enough without humans and demons alike choosing to hurt others. “We’re not slaves to our instincts; we can be different.”

“A demon’s nature is cruelty. You are no different in that regard. How many demons have you devoured with glee? Beings that could think and feel just as humans do? Are their lives worth less than those of humans, simply because they must kill to survive?”

Muichiro fell silent; on impulse, he wanted to reject her words. Demons were cruel because they ate in excess of what they needed to sate their hunger. They were not simply predators; they were killers, killers that had to be stopped from hurting more people. He wanted to say that he was different from them.

But, how different was he really? He turned his hunger for flesh and blood towards demons instead of humans, but he couldn’t claim that he made their deaths fast or painless. The fire burning inside him was stoked by seeing the fear in their eyes. He thought that they deserved it, to feel just as helpless as the people they killed.

Was he really any different in the end?

Muichiro turned around. Nakime stopped brushing his hair and watched him carefully. He couldn’t see her face. He stared, unblinking, and pushed her hair away, revealing a single eye with a pair of kanji written upon them: 'Upper Four'. This close, the characters looked almost scarred into her eye.

“…You’re right,” he said softly, not breaking eye contact.

“Hm?”

“Demons are cruel. I’ve seen it countless times. I’ve felt it, too. I hate demons; I hate them so much it burns me up inside. There’s a part of me that wants to make them suffer. It wants to make them feel the same pain and fear they’ve inflicted on countless innocent people.”

As Muichiro spoke, Nakime remained silent. Her single eye was fogging over, falling under the spell of his gaze. White mist rose up around them. “But unlike you, I can be different. I can go against my nature.” He scratched his palm, and a drop of blood fell into the mist. “So that’s why… I’ll make this quick.”

The mist turned red, howling and collecting behind Nakime in the form of a massive dragon. It opened its jaws and lunged for the entranced demon.

“Blood Demon Art: Freezing Clouds.”

A gust of impossibly cold wind blew past them. Before it could even touch her, the mist dragon was frozen in place, its gaseous form turned to ice before it collapsed under its own weight. Muichiro felt frost forming on his skin as his eyes snapped away from Nakime to see Douma standing at the edge of the platform. When had he gotten here? He wasn’t there a second ago!

“Oh my, when I saw you two sitting together, I truly thought you were bonding! It was so adorable that I just had to stay and watch!” The Upper Moon Two waved a fan over his face; shards of ice still glittered in the air around him. His voice dropped, suddenly sounding a lot less friendly. “I’m glad I did, too.”

The twang of a biwa sounded, and suddenly Muichiro was back in the middle of the platform, far away from Nakime. And then it wasn’t just them and Douma present. Akaza appeared to his right, and in front of him, next to the biwa demon, appeared Kokushibo and Muzan himself.

Muichiro felt his every instinct go on alert; by habit, he looked for his brother, and jumped at the sight of Not-Yuichiro knelt right beside him. His face was set in a grimace, eyes moving and analyzing the situation. It was the first time he had ever seen the shadow look so threatened.

“Don’t move, don’t speak,” the illusion of his twin whispered. Muichiro managed to keep himself from nodding as he looked up at Muzan. To say the Demon King looked displeased would be a massive understatement.

“Well now, what is going on here?” Muzan asked. It was clear he already knew by the way he glared down at Muichiro. “Care to explain?”

Muichiro said nothing. Kokushibo looked down at him, his body tense as he turned his head towards Muzan. “My lord-”

“Oh? Do you have something to say, Kokushibo?” Muzan interrupted him. “Perhaps you wish to take responsibility for his actions? Will you take on his punishment in his stead?”

Kokushibo grit his teeth. He opened his mouth, but then Douma spoke up.

“Lord Muzan, please don’t be so harsh on him! The boy’s only a child; he doesn’t know the rules here!” The Upper Moon's voice dropped low again. “If he has a problem with Nakime, he should challenge her to a blood battle, don’t you agree?”

Huh? Muichiro blinked, confused. A blood battle? What was that?

“Hmm…” Muzan seemed to consider his suggestion. Then he smiled, fangs glinting in the lantern light. “Not a bad idea…”

“My lord, there is no need for this!” Kokushibo cut in. It was by far the most emotion Muichiro had ever heard in his voice; he actually sounded distressed. Was he worried for Muichiro? “He is my student; I will take responsibility for his attempt on Nakime’s life!”

“No, Douma is correct,” Muzan cut him off, his frustration with the Upper One palpable. “A conflict between demons should be resolved in combat. However, it would be inappropriate for a no-rank demon to challenge Upper Moon Four. He’ll have to climb the ranks first.”

Muzan turned towards Nakime, who nodded and strummed her biwa. Immediately, they were all transported somewhere else. Muichiro now found himself on one side of a large arena-like platform. The Upper Moons and Muzan stood on smaller platforms surrounding the main one. And on the other side of the arena, facing him directly, was one more figure.

The newcomer looked around, confused. “What the… What’s going on here?”

Muichiro didn’t recognize him. It was a demon with black hair and tiger-like stripes on his face, wearing a black kimono with a blue obi. But then Muichiro noticed the sword at his hip, and the familiar uniform underneath the kimono. His eyes went wide; he had heard rumors of a demon slayer who betrayed the Corps by becoming a demon and devouring humans. To think that he would find him here, under such circumstances…

But before he could say anything, Muzan spoke. “As we’re all aware, the positions of Upper Moon Six and Upper Moon Five remain vacant. Muichiro, Kaigaku, I will give you the opportunity to fill these positions through a blood battle. Whichever of you two wins this battle will be rewarded with the rank of Upper Moon Five.”

Muichiro felt his blood run cold. That’s what a blood battle was? A fight to determine the ranks of the Upper Moons? No, he didn’t want that! He stood up and backed away, looking for an escape even though he had botched his only chance to do so. Akaza looked annoyed, but he still stood and watched without saying a word. Douma looked far too interested, sitting down with his fan in front of his face. And Kokushibo looked angry, eyes shifting between Muzan and Muichiro. Their eyes met for a second, but Muichiro was the first to look away. What could the Upper One do to help him now, even if he wanted to?

“What do I do?” he whispered to Not-Yuichiro. His body was shaking and he couldn’t stop it.

The fake wearing his brother’s face looked at him, his gaze turning cold. “You have to fight. Muzan will kill you if you don’t.”

“No, I can’t…!” Muichiro whispered back. If he won this battle, Muzan would make him an Upper Moon. There was no way he could let that happen!

The other demon, Kaigaku, called out to him. “Hey, brat! What are you doing just standing there?!”

Muichiro growled back to hide his fear, keenly aware of everyone’s eyes on him. Muzan glared at him once more, then lifted his head to observe them both.

“Begin.”

Wait, what? No, this was too fast-!

Kaigaku moved first. “Thunder Breathing, Fourth Form: Distant Thunder!”

Black lightning leapt from Kaigaku’s body as he unsheathed his sword and swung. A ball of condensed electricity shot towards Muichiro at high speed. Muichiro instinctively tried to break into mist, only to realize he was still wearing his twin’s haori. He leapt out of the way at the last second, the heat from the lightning ball scorching his skin.

Thunder Breathing? There was no question, then; this was the traitor to the Demon Slayer Corps. Muichiro felt fire surging through his limbs, but fear still held him back. How could he fight, knowing what would happen if he won?

Kaigaku leapt forward to close the distance between them. “Thunder Breathing, Second Form: Rice Spirit!”

His sword, clearly a Nichirin sword up close, lashed out five times, lightning flying from every arcing swing. Muichiro stepped back to avoid the attack, then summoned a white mist sword and met the final slash with his own. A bolt of lightning lanced across his cheek, burning and cracking the skin; he hissed in pain but held firm. Their blades pushed against each other.

“You…! You’re the demon slayer who betrayed the Corps!” Muichiro growled.

“Yeah? And who are you supposed to be…!” The other demon’s face lit up in recognition. “Wait, you’re the demon who became a Hashira, aren’t you? Ha, this just gets better and better! Once I beat you, the Upper Moons and Lord Muzan will have to acknowledge my strength!”

Kaigaku suddenly pushed forward, his larger stature knocking Muichiro back. The Mist Hashira leapt away to put distance between them. Kaigaku grinned and lunged, nichirin blade swinging towards his neck, and Muichiro transformed into mist to dodge before reforming and kicking him away. But his opponent recovered quickly, and Muichiro secured Yuichiro’s haori and jumped away as he resumed his attack.

“Ugh, hold still and fight, will you?!” Kaigaku yelled in frustration as Muichiro continued to evade or deflect his strikes without attacking back.

“He’s right, if you continue to stall, Muzan will get angry!” Not-Yuichiro called from the sidelines. “You have to fight!”

Muichiro growled. He didn’t have a choice; he had to do something. “Blood Demon Art: Devouring Mist!”

Instantly, the blood mist rose around him, snapping beasts rearing to face the former slayer. Kaigaku’s grin grew as he raised his blade. “Thunder Breathing, Fifth Form: Heat Lightning!”

Lightning flew from his sword; Muichiro’s eyes widened and he leapt clear as the red mist exploded in flames, a wave of heat and force knocking him to the ground. He cursed himself. This demon wielded electricity; the Devouring Mist was useless against him! How could he have forgotten something so important?

“If you can’t fight, then let me fight for you!” Not-Yuichiro yelled. “Summon me!”

“How do I do that?” Muichiro asked as he recovered and dodged another blow.

“You know how! You just have to want it!”

“Who the hell are you talking to?! Focus on the fight!” Kaigaku yelled, refusing to let up on his assault. “Thunder Breathing, Sixth Form: Rumble and Flash!”

Muichiro instinctively jumped away, but the range of the lightning strikes was larger than he anticipated. He heard a tearing sound and the smell of burning fabric, and for a moment his mind went blank. And then a sharp pain forced him back to reality as his right arm was sliced from his shoulder. He stumbled back, watching as it landed on the ground.

His eyes went wide; the haori’s sleeve on his severed arm was singed and torn, the mist patterns barely discernible beneath the blackened fabric. Looking down, he saw the rest of the haori in a similar condition, ruined by the same black lightning that left charred cracks across his skin. But that pain was nothing compared to his horror at the state of his brother’s prized possession.

“What’s with that face? Don’t tell me you’re upset about some dumb haori.” Kaigaku’s voice brought him back to the present. The demon stomped down on his severed arm, snapping the bone beneath his foot. Muichiro didn’t react to the sound, but seeing the demon’s zori dirty the haori sleeve made his mind and heart go numb.

“…Give it back,” he breathed, voice barely audible.

Kaigaku raised an eyebrow, then smirked. “If you want it back, then come and get it.” He ground his foot further into the sleeve. “If you even can.”

Silence greeted his challenge. And then…

“Moon Breathing, First Form: Dark Moon, Evening Palace.”

“Huh-” Kaigaku stumbled as his leg was suddenly separated from his body. Muichiro surged past him, snatching up his lost arm from underneath the demon’s foot and reattaching it to his shoulder in one motion.

“What the hell?” Kaigaku growled, all smug bravado gone in an instant. “How did you…?”

Muichiro’s mist sword lashed out, cutting a line across the other demon’s throat as he backed off just in time. Kaigaku growled and readied another Thunder Breathing technique, electricity sparking around him, only to be enveloped by a cloud of white mist. Muichiro leapt back while tossing a spray of his blood into the mist, and the cloud turned red before igniting around Kaigaku’s electrified form.

Kaigaku stumbled out of the explosion, body near unrecognizable, arms burnt to crisps and charred legs barely keeping him standing. The red mist gathered around Muichiro again, his sword turning a vivid crimson.

“Moon Breathing, Second Form: Pearl Flower Moon Gazing.”

Three crescents cut through both of Kaigaku’s arms and then finally his head, sending it flying into the air. Muichiro looked up to follow it, and the blood mist roared, opening its maw and surging towards its prey.

“That’s enough. Douma.”

For the second time, a freezing gust of wind turned the Devouring Mist to ice just before it could close its jaws around Kaigaku’s head. Muichiro stumbled, the icy chill bringing him back to his senses. He looked around, seeing Kaigaku’s head hit the ground and roll away, then up to the watching Upper Moons. Akaza seemed impressed, while Douma grinned ecstatically. But Kokushibo only watched on with trepidation. Muichiro felt the same feeling building up inside him as he realized what had happened.

He had won the blood battle.

A slow clapping filled the air. He looked up at Muzan, hands coming together slowly, mockingly, to celebrate his victory. The Demon King smiled maliciously. “It seems we have a winner.”

Muichiro’s body shook. Again he looked instinctively for his older brother, but he couldn’t see him. The fake Yuichiro had disappeared, leaving him alone to face the consequences of his success.

The platform carrying Muzan lowered to be level with the arena, and he stepped forward, each footstep seeming to echo in the vastness of the castle. Muichiro stood frozen in place; he didn’t dare try to retreat. He only watched as Muzan came to a halt in front of him, staring him down with a satisfied grin.

“Congratulations, Upper Moon Five.”

Muichiro saw his hand move a moment too late. And then he couldn’t see anything but red. Liquid fire surged through his eyes as he fell to the ground, hands rising to claw at his face, trying and failing to stop the horrible burning. Something was carving itself into his irises, like after line like a heated knife. Distantly, he heard his own voice screaming.

“Be quiet,” Muzan’s hiss was similarly far away, until a sharp sting in his neck cut off his voice. The painfully familiar sensation of Muzan’s blood flowed into him, but something was different this time; it hurt, but he felt stronger. Power coursed through his limbs, as welcomed as an oasis in a desert. But then Muzan removed his needle-tipped hand, and suddenly all that strength disappeared. Muichiro collapsed to the floor, unable to move. He felt hot, but his body wouldn’t stop shivering. Blood writhed in his veins, painful and nauseating, addictive and exhilarating.

He wanted it out.

He needed more.

Someone, please… help me…

“Well done. A good dog deserves a reward, don’t you think?” Muzan said mockingly. “Kokushibo, accompany him to the dungeons.”

Kokushibo said nothing, his eyes narrowed in helpless frustration. Nakime strummed her biwa, and he and Muichiro were instantly transported somewhere else. Muichiro’s eyes adjusted to find a dark cellar-like location, lined with barred cells. And in the cell directly facing him was a demon chained to a wall, withered and starved.

Kokushibo’s solemn voice broke the silence. “This demon attempted to give information to the demon slayers… in exchange for sparing his life. However, we were able to… retrieve him before that could happen.” His six eyes looked towards Muichiro, who couldn’t tear his gaze from the demon. “…Lord Muzan has given you permission to eat.”

At his words, the demon in the cell tried to shrink away from them. Perhaps it knew who Muichiro was; perhaps it did not. But the fear in its eyes stirred something in Muichiro, something he couldn’t fight. Pain radiated from his eyes and dulled his mind. His limbs felt stronger, ready to pounce, and the aching in his stomach was more agonizing than ever. He was so, so hungry.

The Devouring Mist rose up at his unspoken command, creeping through the bars of the cell. Even if the demon hadn’t been chained up, it had nowhere to run.

Muichiro felt tears run down his face as the mist descended, its roar drowning out the demon’s screams.

—

It took an hour for that demon to die. Not because it was strong, or tough, but because Muichiro wouldn’t let it. Tear and feast, tear and feast, let it heal, then tear and feast again. Until the hunger was satisfied.

Except he was still hungry; he’d allowed the demon to die when he’d eaten enough to regain his senses, the guilt too much to bear. He really was no different from any other demon.

When it was all over, Nakime teleported him back to his room. In the time he’d been gone, a new addition had been made to the room’s sparse decor: a mirror, propped up against the far wall. When Muichiro first saw it, the urge to smash it to pieces had been irresistible.

But before he could, he saw himself in its reflection. His anger drained away, and he crept closer, as if his own reflection could leap out and attack him. He stopped in front of the mirror and stared, looking into his own eyes. Beneath their ever-present glow, black lines of kanji scarred his irises, seeming to absorb the light around them. Even reversed, the characters were unmistakable.

Upper Five. The same rank as the Upper Moon he and Yuichiro had killed. Was Gyokko laughing at him from hell?

Before he could stop himself, Muichiro’s claws slashed through his reflection. Glass cut into his skin, but pain like that was nothing to him. The pieces of the mirror laid shattered, reflecting him more than ever. Muichiro couldn’t scream. He couldn’t cry. There was a tempest inside him, but he had no means to release it in any way that would matter. The undeniable truth of his reality was carved into his eyes.

Muichiro was going to die here.

There was no hope for him anymore. Either Muzan would kill him, or the demon slayers would end his misery once they saw what he’d become. An Upper Moon. A traitor.

Traitor.

Traitor.

Traitor.

“That’s right. You’re a traitor to everything the demon slayers stand for. They’ll never take you back now.”

Muichiro jumped and whirled around. The shadow, still wearing Yuichiro’s form, smiled down at him. His words didn’t register in Muichiro’s mind; all he could process was pain. “You…! You left me! I needed you and you weren’t there!”

He didn’t know who he was even yelling at anymore. The shadow? Yuichiro? They had both left him alone.

Not-Yuichiro knelt down and pulled Muichiro into a gentle hug. Despite his fury, the illusion of his brother’s touch soothed some of the storm inside him. “Hush now, I never left. I am always with you, even if you can’t see me. You can’t give up now. This is the opportunity you’ve been waiting for.”

“What do you mean?” Muichiro asked. He was marked as an Upper Moon, one of Muzan’s strongest warriors. How could that possibly be a good thing?

“Can’t you feel the power running through you? The strength of an Upper Moon? Muzan has made the mistake of elevating you beyond any normal demon. This is your true chance to escape him!”

“True chance…? Wait…” Muichiro pulled away, looking into those familiar teal eyes, alight with joy at the suffering he’d just gone through. “Did you know this would happen?”

Not-Yuichiro frowned and tilted his head. “Did I know? No. I exist within you; I only know what you know.”

“But-”

“The escape attempt was genuine. If you had succeeded and gotten away from here, I would have been satisfied. But this has turned out better than I could have ever hoped. You have power now, and you can use that to gain even more power!”

“…No… no, I… I didn’t want power…” Muichiro suddenly found it hard to speak; his voice was barely above a whisper. “I just wanted to go home.”

Back to Yuichiro. Back to his friends. Back to where he was safe and loved.

The shadow’s eyes narrowed. “That won’t happen anymore.”

Muichiro felt his heart crumble. He already knew that. “…What do I do now?”

“Now? You survive. That’s all you need to do. Everyone is against you, except for me. You can trust me; I will keep you alive.”

“But what are you?” Muichiro asked, his voice breaking. This was all too much, and he didn’t know how to handle any of it. “Why are you here? Why are you in my head? Why do you care?”

Silence answered him, and then the fake heaved a sigh. “…Is it really so hard to understand? I exist because of you. Did you ever wonder why your power takes the form of mist? Because things become lost in the mist. Vile things, dangerous things. The mist swallows and hides them all.”

“But what does that have to do with you?”

“It has everything to do with me. Remember that night on the mountain, the night you lost control. You buried everything that you couldn’t bear to face down into the mist. Your rage, your hunger, your hatred. And then finally, you buried even your sense of self. All of that came together to create me. You made me from everything you hated about yourself.”

Muichiro could only stare in horror. Then, the shadow really did come from him. It wasn't just some hallucination, it was everything wrong with himself. Everything he didn’t want to be.

“…Do you hate me, then? If you’re everything I rejected, you must hate me for it, right?” That was the only explanation for its cruelty, the way it insulted and taunted him despite claiming it cared. It was just pretending.

But the shadow leaned in to hug him again, unfittingly tender in its touch. “No, I don’t hate you. I am a part of you, and my only wish is for you to live. As long as you survive, everything else can burn.”

It was at that moment that Muichiro finally understood. The shadow truly did want to help him. But only because helping him helped it as well. If Muichiro died, so would the shadow. It didn’t care about his happiness or his humanity. It was survival instinct, self-preservation at all costs. It was the demon inside him that wanted to live no matter what.

But if this monster was the part of him that wanted to live, then Muichiro would rather be dead.

The illusion of his brother stood up, looking down on him again. “The final battle approaches. Everyone will be too busy fighting to focus on you; that will be your chance. There will be hundreds of demons to feast upon. Kill them. Kill the Upper Moons. You have the power to do so.”

“…And what about Muzan?” Muichiro asked, already knowing the answer.

“…Muzan is not your concern. However he wronged you, your life is tied to his; if he dies, so do you. You have no reason to fight him.” The shadow looked into his eyes, coldly logical. Muichiro glared back. It was the response he expected, and confirmed what he already knew.

The shadow would not allow him to die. Not by his own hand. The only way he could die would be in battle, against an opponent he could not overcome. Muichiro came to a decision, right then and there.

On the night of the final battle, he would kill every demon in this castle, and then the new Upper Moon Five would fall to the blade of the Mist Hashira.

Chapter Text

“Nakime.”

“Kokushibo, welcome back. What do you require?”

Kokushibo felt a sense of relief to be back in the Infinity Castle. By order of his lord, he had been away on a mission to locate the demon who conquered the sun. He’d searched for five nights without success; Ubuyashiki’s skill for remaining hidden was as impeccable as ever. But it mattered not. He knew the mission was mere busywork, meant only to keep him away from the castle, and away from his descendant.

But Muzan had called him back unexpectedly, which could only mean one thing. “Is it true? You have… located the Ubuyashiki Estate?”

“It is,” Nakime nodded. “Lord Muzan is preparing to depart as we speak.”

Kokushibo stayed silent, thinking. Going after Ubuyashiki now would make a clash with the demon slayers inevitable. If his lord was making a move, it meant he believed he had Muichiro under control. He felt unsettled by the thought.

“How is… Muichiro?” he asked. He hadn’t seen him since the day of the blood battle.

Nakime frowned tightly. “…He is well. He has not left his room since your departure. He seems to spend most of his time training.”

“I see…” Kokushibo nodded. While that didn’t soothe his concerns, it was good to know he hadn’t been harmed any further. He wanted to see his descendant right away, but first he had something else to bring up. “Nakime… I believe it is time… that Muichiro had a space of his own here.”

Nakime took a moment to respond. “He has a room already.”

Her voice was tense; it was clear she was unhappy with the boy after his attempt on her life. While understandable, Kokushibo still found himself annoyed. “He is… an Upper Moon as well, now. And furthermore… I am ordering you… to give him his own space.”

Nakime sighed. No matter her reservations, she was unable to refuse a direct order from her superior.

“Fine. What kind of space do you want for him?”

—

Against all odds, Muichiro’s life became easier after becoming an Upper Moon. Or at least, it became simpler.

He no longer had his daily torture sessions with Muzan. In fact, he no longer saw the Demon King or any of his Upper Moons; even Kokushibo had stopped coming around. He spent all his time in his room with only the shadow, still masquerading as his twin, for company. He had no idea how much time had passed; without anything to do, time was a blur. All he could do was train to distract himself from how lonely he felt.

So when a knock came from outside his door, and he saw that familiar silhouette through the screen, Muichiro was immediately on edge.

Why is he here? he thought to the shadow.

Not-Yuichiro frowned. “I suspect something has happened. Stay alert.”

Muichiro nodded and waited as the door opened and Kokushibo entered. The Upper One’s eyes locked onto him first, and Muichiro suddenly felt self-conscious with his marked eyes and Yuichiro’s tattered haori draped over his shoulders. Then his gaze moved to the shattered mirror with its pieces still scattered across the ground, and he felt even more pathetic.

But Kokushibo did not acknowledge any of it. He blinked and lowered his head. “I have been away on a mission… by Lord Muzan’s orders. I apologize… for not informing you before I left.”

Ah. So Kokushibo hadn’t left him alone willingly. But he also hadn’t tried to disobey his orders to stay, either. But Muichiro wasn’t surprised; that was just how the Upper One had always been. He cared, just not enough to fight for him.

…No, that wasn’t entirely true. “Teacher?”

“Hm?” Kokushibo blinked again.

“Before… before the blood battle, were you trying to stop it? For my sake?” he asked. After all, Kokushibo had raised his voice against Muzan, something he suspected would get any lesser demon killed. He had tried to take Muichiro’s punishment, but the Demon King wouldn’t allow it.

Kokushibo’s eyes widened. “I…”

“…Thank you.” It was hard for Muichiro to smile these days, but he meant what he said. Kokushibo had been the one person who never abused or ignored him while he was imprisoned here. Sometimes he was even tender, beneath his cold exterior. Muichiro was his descendant, which meant Kokushibo had once had a family. Was this what he was like as a father? He left a lot to be desired, certainly, but Muichiro could see the effort.

Kokushibo was silent for a long moment, but when he spoke, his voice was heavy. “Do not thank me. I could do nothing to protect you.”

Muichiro frowned. That was true; the evidence was burned into his eyes.

Not-Yuichiro glared at him. “You’re letting your feelings blind you. He caused all this; he doesn’t deserve your forgiveness!”

Muichiro flinched and turned his gaze downward. “Um… did you… come by just to see me?”

Kokushibo shook his head. “There is something… I wish to show you. Come with me.”

Something he wanted to show him? What could it be? But Muichiro just nodded and followed the Upper Moon. He’d find out soon enough.

They stepped out of the room, and Kokushibo called out, “Nakime.”

The familiar biwa reverberated through the hallway, and suddenly they were somewhere entirely new. An unexpectedly bright light shone in Muichiro’s eyes, and he squeezed them shut with a hiss. But his body didn’t burn under the light, and slowly he opened them again in a squint.

Muichiro gasped, his eyes shooting wide open. “What… What is this?”

His childhood home stood in front of him. The old house was just as he remembered it, before the fateful demon attack that left it ruined and stained with blood. The ginkgo trees were in full autumn bloom, their leaves a brilliant gold. And this light… was this sunlight? But it was when he looked up that the illusion was broken, the Infinity Castle’s walls and lanterns visible high up in the air.

It wasn’t real. It wasn’t actually his home. But looking at it brought tears to his eyes. That swirling tempest of emotions was building up inside him again; he didn’t know how he should feel. Sad for what he had lost? Angry for being reminded of it?

Kokushibo’s voice brought him back to the present. “This is your personal space within the Infinity Castle. A space to do with as you please… no one else may touch it but you.”

“But why… how…?” Muichiro couldn’t understand. The only one who knew about his old home was… “Did you make this?”

Kokushibo nodded. “I instructed Nakime to construct it. I thought… you would find it comforting.”

Comforting? Muichiro wasn’t sure comforting was the word for it. If anything, this perfect replica of his home was disconcerting. He went to look around a certain tree, and sure enough, he found the first kanji of his and Yuichiro’s names carved into the back of the trunk. The level of detail present was frightening. “It’s all so… exact.”

“I sought to replicate… every detail I could remember… to make it look as accurate as possible.”

“It’s not autumn, though,” Muichiro pointed out. At this time of year, the ginkgo leaves would still be green, not gold.

“I… thought you would prefer the color.” Kokushibo admitted, almost sounding sheepish.

“…Thank you.” Muichiro couldn’t think of anything else to say, so he left it at that. He still didn’t know how to feel about being gifted a fake version of his home after being stolen away from his real one. But even if he escaped from here, he couldn’t go back. Not anymore. This facsimile would have to be enough.

A moment of silence passed. The illusory sunlight was cold on his skin, reminding him of how fake this all was. Kokushibo spoke again. “There is… something else I must tell you.” Muichiro looked his way, and he continued. “Lord Muzan… has discovered the location of the Ubuyashiki Estate.”

Muichiro froze, fear alighting in his heart. Muzan had found the Headquarters? But how? And what did this mean for the Master and his family? Were they in danger? But he couldn’t do anything to help them; he was still a prisoner here.

No, more than that, he was an Upper Moon now. Would they even want his help in the first place?

But Kokushibo was still looking at him, and Muichiro couldn’t let those feelings show. He pushed the fear down and fought to keep his voice level. “…I see. Then, the final battle is here.”

Tonight, it would all come to an end. This war between demons and demon slayers would see its conclusion, one side wiped out for good. And… Muichiro would see his end, as well.

But something about knowing that felt… freeing. His own words made his heart feel strangely light. It didn’t make sense. This battle would spell untold amounts of death for both sides. The Hashira, his friends, his brother - they were all going to be right in the thick of it, risking their lives against the demons. So why did thinking about the upcoming fight bring him a measure of peace?

“Oh, is it not obvious?” Not-Yuichiro asked, suddenly right beside him. Muichiro jumped and backed away. “You’re far more selfish than you realize. The pain of your friends? Their possible deaths? None of that matters. All that matters is that your pain stops, right?”

Muichiro felt a stab in his heart, but he couldn’t refute the shadow’s words. How could he, when they were true?

The shadow’s malicious grin widened. “Of course, if you want to save them, you know what you have to do.”

Muichiro did know; he looked back at Kokushibo. He would have to kill him tonight, the same as all the other demons. His Teacher, who taught him Total Concentration Breathing. Who taught him Moon Breathing. Who brought him to this hell and was complacent in his suffering. Who was powerless to help his own family. He had every reason to hate him.

And yet, that just seemed so… pointless. It was clear that Kokushibo’s inaction was because he didn’t have the power to stand up to Muzan. For all his strength, he was still at the mercy of the Demon King’s curse. Kokushibo was as much a prisoner as he was. One in a prison of his own making, but a prisoner nonetheless.

No, Muichiro didn’t hate him. In fact, he still clung to his small moments of kindness, those moments when his Teacher did act and risk Muzan’s wrath for his sake. They were all he had to keep himself sane now; he had no hope of rescue, and the symbol of his brother laid in tatters on his shoulders. Kokushibo was all he had left. So even if he had to kill him…

“Teacher, can I ask you a question?”

Kokushibo eyed him with confusion. “What is it?”

Muichiro forced himself to smile. His fleeting peace was gone, and suddenly he felt uncertain about the future. What awaited him after death? He needed assurance, some hope in the face of his karmic punishment, that he wouldn’t have to face it alone.

“When we die and go to hell tonight… will you wait for me?”

—

“When we die and go to hell tonight… will you wait for me?”

Kokushibo suddenly felt cold. What kind of question was that? No, why was Muichiro, of all people, asking that? To suggest that not only was death inevitable, but also damnation? Kokushibo knew he would be condemned after death for his sins, but his descendant had done nothing wrong.

And that wording - wait for him - as if Kokushibo would die before Muichiro. As if he was certain that would happen. But Kokushibo had no intention of dying, and he certainly had no intention of doing so and leaving Muichiro alone.

“I will not…” He saw Muichiro’s smile fall, and continued before he could speak. “You will not go to hell… because you will not die tonight… I won’t allow it.”

He couldn’t protect Muichiro from Muzan, but he could protect him from everything else. As long as Kokushibo drew breath, no demon or Hashira would touch him.

But Muichiro just stared, eyes wide and glow flickering, his body deathly still. Then he sucked in a breath - Kokushibo recognized the sound of laughter - and smiled again. A smile that didn’t reach his eyes, and which bared his sharp teeth.

“…It’s funny that you think you can stop it,” Muichiro’s voice was shaking. “You can’t even fight against Muzan. How can you fight against the gods? Against fate?”

The chill Kokushibo felt grew stronger; he became aware of his heart beating faster in his chest. This feeling was more than dread, it was fear of the child right in front of him. Fear for him. Those fatalistic words were coming from the same boy who had told him he was not bound to the path he chose. That he could choose to be different.

Where was that boy now?

“…Did you not tell me… that I could change, as long as I was alive?” Kokushibo asked, afraid of the answer he might hear.

Muichiro’s broken smile disappeared, his face disturbingly blank. His voice was just as empty as his expression. “Some things can’t be changed.”

The Upper One couldn’t summon the courage to respond. What had Muzan done to him?

…No, what had Kokushibo done to him?

Muichiro’s empty expression cracked as his eyes narrowed and his lips turned in a snarl. “After everything you’ve done… you can’t even give me this.”

Kokushibo noticed the boy’s claws digging into his palms, red mist rising from the wounds. He moved to stop him, only to freeze as the mist took shape. Muichiro seemed unaware of it, his gaze trained to the forest floor. But the image of Yuichiro in the mist was unmistakable as it curled possessively around him, hollow eyes glaring at the Upper Moon One with unveiled malice.

What… what was that? “Muichiro-”

“Go away. You said this was my own space, right? Well I don’t want you here.” The red mist dispersed as Muichiro shook his head and stalked off towards his childhood home without waiting for a response. Kokushibo could only watch as he closed the sliding door behind him, leaving the Upper Moon alone under the golden ginkgo trees.

But despite Muichiro’s order, he didn’t leave. Slowly and quietly, he stepped forward until he was in front of the house. There was a window just to the side of the door, and he peered through to see Muichiro curled up beneath one of the futons. He could easily make out the young demon’s face in the dark, his eyes closed and wet with tears as he tried to sleep. Was it his imagination, or did he look younger?

Kokushibo peered closer. He was younger, back to the age of eleven, when Kokushibo had first transformed him. He had been so small back then, so frail. A child too young and kind for this world. Much like…

A memory flashed before his eyes. A young boy with red hair and eyes and a birthmark like a flame on his face. He was smiling as he clutched a wooden flute in his small hands, looking up at the one who gave it to him with love and adoration.

Yoriichi…

Muichiro was so much like Yoriichi. Both prodigious talents who took to wielding a sword with such natural ease. At first, Kokushibo had only focused on that. But over time, he noticed other similarities. They were both soft-spoken and polite. They were both observant and wise beyond their years. And they both possessed a kind heart that cared deeply for the people around them, and for the world as a whole.

But Kokushibo was not that kind of person. He was envious and cold, selfish and cruel. Everything his twin was not. And yet, he wanted to be strong like his twin. So much so that he gave up everything. His name, his family, and any chance he had of reforging his bond with his brother; he trampled over all of it in the name of power.

But what power did he really have? Certainly none with which to stand up to his lord; Muzan could kill him in an instant if he chose so. He could only watch as Muzan tortured his descendant day after day. Even when Kokushibo had defended Muichiro against Douma, the thought of his lord’s anger had briefly paralyzed him. For all his strength as the Upper Moon One, he couldn’t protect Muichiro from Muzan’s wrath.

And yet, Muichiro wouldn’t even be in this position if not for Kokushibo. Why did he bring him here? Why did he not refuse his orders? 

He knew the answer: because to do so would mean going against his loyalty to his lord. And a samurai was defined by his loyalty. That was why he followed Muzan all these centuries. Everything he once valued was gone. His family name was lost. His companions were dead by his hand. And the brother he so longed to surpass had long left this world behind.

Kokushibo had nothing left but his loyalty to define him.

Until he found them.

Muichiro and Yuichiro, his last living descendants. The last traces of his mark on this world. The last pieces of evidence that he had once been human.

Admittedly, Yuichiro reminded him too much of himself. But Muichiro was different. He was so unlike Kokushibo, innocent and perhaps naive, but he saw the good in people like him. He evoked feelings of warmth and affection, the desire to protect, that he hadn’t experienced since he was human, since he was a father himself.

That scared him. After centuries of feeling nothing, to feel so human again was terrifying. But therein lied his realization.

Muichiro was his second chance. To succeed where he had failed Yoriichi. To succeed where he had failed his own son. To have a family again.

And he was losing that chance. His inaction had isolated Muichiro and drove him to this point, to think that death was his only escape from the hell Kokushibo had dragged him into.

He had to do something. Anything to fix this. But the answer came to him immediately.

Muichiro needed his brother. Not whatever illusion was haunting him, but his real brother. His twin and other half.

Tonight, Muzan would launch an attack against the Ubuyashiki Estate and the Demon Slayer Corps. His victory, his pursuit of immortality, was imminent. He would not be focused on Kokushibo; that would be his chance.

Kokushibo turned and left the false forest of golden ginkgo trees behind. But he would return; he would not fail Muichiro again.

—

A sea of red mist stretched out before him. Yuichiro kept his hand on his sword, alert for danger, but the feeling of anger and hostility was all around him. He saw movement out the corner of his eye and turned. His grip on his sword’s hilt tightened.

“You. What do you want now?”

The shadow that resembled Muichiro glared at him, and he glared back. If this came to a fight, he wouldn’t be caught off guard again. But the shadow’s stance was neutral; it simply stood there, making no move to attack.

…You’re here again.

There was that voice, so much like Muichiro’s and his own at the same time. Yuichiro scowled. “Where’s Muichiro?”

Where? He’s all around us; this is his dream, after all. You’re just a trespasser.

Yuichiro growled; he really hated this thing’s attitude, but it confirmed what he suspected. Somehow, he had connected to his twin through his dreams; this was his chance to reach out to him. “Let me through, I have to find him.”

I think not. You had your chance to keep him safe and you failed. I will be the one to protect him now.

“Yeah? And what the hell are you, anyway?” Yuichiro scoffed. Even if the shadow was right that he had failed to protect his brother, he didn’t trust it for a second with Muichiro’s safety. He could feel it, the bloodlust of a demon emanating from this thing in front of him. The shadow closed its eyes.

As if you could truly understand. I am what he refuses to be. What he denies about himself. But most importantly…

As the shadow spoke, the darkness enveloping it fell off like autumn leaves shed from a tree. Yuichiro prepared himself for a fight, only to freeze as the darkness fell away completely to reveal the form underneath. It almost looked like Muichiro, but Yuichiro knew better; garbed in his black mist-patterned haori, it was a perfect mirror of himself.

“…I am that which will keep him alive.” What was once the shadow spoke in his voice.

“…What the…” Yuichiro was momentarily at a loss for words. How was this possible? But his anger soon returned. “What the hell are you trying to pull here?!”

“It’s simple, really. You’ve failed, so I’ve taken your place. A big brother should try to help his little brother, to make him strong so he can survive in this world. But all you’ve done is hold him back from reaching his true potential. Shameful, don’t you think?”

“Like I give a damn what you think!” Yuichiro snapped. Seeing this thing smile so smugly with his face pissed him off. “You don’t have any idea what you’re talking about! Muichiro and I do make each other stronger! It’s by fighting together and supporting each other that we’ve come this far!”

“Yes, you’ve come this far and look at what’s happened,” the fake Yuichiro continued to taunt him. “If only you could see what’s become of him because of your failure.”

Yuichiro’s anger at the fake was doused by a sudden rush of fear. What did that mean? Did something happen to Muichiro? “What are you talking about?”

“Oh, I really shouldn’t say. It’s not my place to tell.”

Yuichiro snarled, his body shaking with renewed fury. This piece of…! But he realized what was going on and fought to get a handle on his temper. It was trying to get a reaction out of him, to scare him. He had to remain calm.

“…I don’t care what you say. I’m not giving up on Muichiro. Wherever he is, I’ll find him.”

“You should reconsider that. If you go there, you’ll be playing right into his plan.”

“I’m not scared of whatever Muzan has planned.”

“I’m not talking about Muzan.”

Yuichiro blinked. Not Muzan? What the hell was it talking about, then?

But the fake him didn’t elaborate. It looked away, placing a hand to its chin as it whispered to itself. “…Then again, you might be the only one who can stop this foolish endeavor…”

For a moment, it looked frustrated, even angry, but the emotion was gone as quickly as it came. It turned back to Yuichiro with a grin on its face. “You wanted to know where he is? I can tell you.”

Huh? Wasn’t it trying to keep him away just a minute ago? The sudden change unnerved Yuichiro, but he needed to know. He nodded, and it looked pleased.

“…The Infinity Castle. A space separated from reality. The stronghold of the Demon King.” The illusion’s pupils narrowed to slits, and when it smiled, its teeth were sharpened and deadly. “Find him. Save him. Better hurry, though, before it’s too late…”

It raised a hand, and the blood mist roared and closed in on them both.

—

Yuichiro snapped awake to his dark room. The sight of it frustrated him; it had been five days since he first had that dream, and he’d been so close to finding Muichiro. But that damned shadow got in his way again. Everything about it put him on edge, now more than ever. It could take his form, something that was both insulting and terrifying. Could Muichiro see it like that? Could he talk to it? Was it pretending to be him?

But despite his new worries, the shadow had also given him information. Muichiro was in a place called the Infinity Castle; it was Muzan’s stronghold, and a place separated from reality, whatever that meant. Most likely, it meant it was indeed a place humans couldn’t access, but just knowing about its existence could be valuable information to the Corps.

With that in mind, Yuichiro got up and changed into his uniform, then grabbed his sword. As he moved to leave, his gaze landed on two origami cats set on the dresser, black and white with turquoise ears. The sight of them evoked a feeling of sentimentality, and he found himself pocketing them before opening his door to depart.

It was dark out in the hallway, but he could hear sound coming from the kitchen. Aoi was still awake. Following the sound, he found the girl still washing dishes from dinner; it seemed he hadn’t slept for very long, then.

“Hey,” he called, trying not to startle her. Even so, Aoi jumped before turning and relaxing at the sight of him.

“Oh, it’s just you. I thought you went to bed?”

Yuichiro shrugged. “I had a weird dream.” He left it at that, unwilling to explain the details when he didn’t fully understand them himself.

Aoi nodded in understanding. She didn’t push it; even though he’d been trying to get more sleep lately, nightmares were still a frequent occurrence.

“I’m going to the Ubuyashiki Estate. There’s something I have to discuss with them,” Yuichiro informed her.

“Oh, okay. I’ll probably be asleep when you get back, so have a good night.” With that, Aoi turned back to the dishes. But Yuichiro wasn’t finished just yet.

“Um, Aoi?”

“Hm?” She stopped again and looked back.

“I just… wanted to say thank you, for everything you’ve done for me. I know I’ve been saying that a lot lately, but I… I want you to know that. That I appreciate you always being here for me.”

Aoi shook her head and sighed, but her smile showed she didn’t really mind his constant words of gratitude. “You’re welcome, Yuichiro. I’m just glad you’re finally starting to act like your old self again.”

Yuichiro found himself smiling back. He couldn’t say he entirely agreed - he would never feel like himself until Muichiro was safe again - but he understood her sentiment. Taking time to eat and rest and talk to his friends this past week had helped him feel more grounded than he had in a long time. Part of him still felt guilty for being happy while Muichiro was suffering, but… that just meant he had to succeed in rescuing him. So his twin could be happy again, too.

“Yeah. I’ll see you in the morning, then. Good night, Aoi.”

They bid each other farewell, and Yuichiro left for the Ubuyashiki Estate. The night was still young and he had plenty of time, but he walked quickly, hoping to catch Amane before she went to bed. Maybe if he was lucky, he could even share a few words with the Master, too.

He reached the estate after about an hour of travel, finding it quiet and peaceful. Two of the Ubuyashiki girls, Hinaki and Nichika, were playing with a ball in the courtyard, and he gave them a smile and wave as he passed by.

The girls waved back and pointed at an open doorway into the manor. Yuichiro nodded gratefully and went that way. Coming closer, he saw both Master Kagaya resting on a futon inside and Amane leaning over him, tending to his illness.

“…Ah, this presence… is that you, Yuichiro?” the Master asked, his voice straining with each word. Yuichiro couldn’t help but gasp at the sight of him; he knew his sickness was bad, but now he could see that there wasn’t a bit of skin untouched by the disease. Most of his face was covered in bandages, and he barely had the strength to turn his head.

“Yeah, it’s me.” He sat down and bowed. Seeing the Master in this state made Yuichiro’s heart squeeze painfully, but he had to keep a strong face.

“It’s been a long time… how are you faring?”

“I’m… doing better.”

Master Kagaya smiled; even that much seemed to strain him. “I understand. But, Yuichiro, do not worry so much… you will see Muichiro again. I am sure of it.”

“…Right.” He had no reason to doubt the Master, but he hoped their reunion would not be a tragic one.

“Is there a reason you came here, Yuichiro?” Amane asked him.

Yuichiro nodded; she knew him well. “I learned something important about where Muichiro is.”

Amane’s eyes widened slightly, but her face remained composed. “You did? How?”

Yuichiro knew the answer to that, but he wasn’t sure how to actually explain it. Would they even believe him if he said he heard it in a dream? But he decided to just be honest, though he left out the part about hearing it from his brother’s shadow.

“I think I somehow connected to Muichiro through our dreams. He told me he’s somewhere called the Infinity Castle. It’s Muzan’s stronghold, and it’s in a place separate from our reality.”

“The Infinity Castle… I see…” Master Kagaya breathed, “It must be a Blood Demon Art… so that’s how he’s evaded us for so long.”

Amane looked sadly at her husband, then lifted her head to smile at Yuichiro. “Thank you for this information, Yuichiro. While you’re here, might I trouble you to come with me to the kitchen? I would appreciate your help.”

“Um, sure, that’s fine,” he agreed, and with a quiet goodbye to the Master, Yuichiro stood and followed Amane further into the manor. She led him to the kitchen, where she got to work collecting an assortment of powders to mix together.

“Could you boil some water for me?”

Yuichiro nodded and did as she asked. He figured she was making medicine for the Master, but it didn’t seem like something that she really needed help with. Most likely, she just wanted him away so her husband could rest.

And indeed, the next words she spoke confirmed that. “My apologies. The Master’s illness has taken a heavy toll on him, and he needs to conserve his strength.”

“It’s okay, I understand.”

“I heard about what happened with you and Sanemi from Ginko. I’m glad that he was able to help you.”

Yuichiro sighed; of course it was Ginko who told her. He hoped this wouldn’t start some rumor that he and Shinazugawa were friends now. “Well, I guess I needed the wake up call. I can’t help Muichiro if I’m not taking care of myself, right? And I know you’ve been telling me the same thing, even though I didn’t want to listen. I’m sorry.”

“There’s no need for-”

“I know, that’s what everyone keeps saying. But I still need to say it. And I really am grateful to have had you and everyone else to support me. So what I’m trying to say is… thank you.”

Somehow, he felt more nervous apologizing to Amane than to Aoi or any of his peers. But Amane listened intently, and when he was done, a warm, kind smile graced her lips.

“You’ve come a long way, Yuichiro.”

“Ugh, don’t tell me you’re gonna start talking about that, too?” Yuichiro groaned. Hearing everyone tell him how much he had changed was embarrassing.

“It’s something that needs to be said. When you and Muichiro first came here, you were so cold and untrusting. And I don’t blame you for being that way, given your circumstances. But it makes me happy to have watched you grow over these three years. You’ve become such a brave and caring young man.”

“Seriously?” Yuichiro could feel his face heating up. “What are you, my mom?”

As soon as those words were out of his mouth, he blushed even more. Did he really just say that? The fact that Amane didn’t even look surprised made it worse; in fact, she looked amused. He could almost die of embarrassment.

“Do you think of me that way, Yuichiro?”

“Eh? U-Um, well, I…” Yuichiro’s brain wasn’t working right to form a response. Did he? He knew Muichiro would say yes in a heartbeat; he had always seen Amane as a second mom of sorts. But Yuichiro had only just started to sort out his own feelings for his parents. He couldn’t replace them, but who said that he had to? Maybe, with time, he could come to think of her that way.

But a sudden, soft ‘meow’ saved him from having to answer her. He breathed a mental sigh of relief as they both turned towards the window and a familiar cat appeared out of nowhere. It hopped down to the floor and approached Yuichiro, meowing again. He knelt down to pet it.

“Uh, Chachamaru, right?” He wasn’t sure if the cat understood him, but it purred and leaned into his touch. He then noticed the pouch in its back with a little note tied to it. He moved to untie the note and saw that it was addressed to him.

Upon opening it up, he immediately recognized Tamayo’s handwriting.

Yuichiro,

I hope Chachamaru finds you well. I wish I could deliver this message in person, but preparations for the fight against Muzan have kept me busy. I am pleased to tell you that the cure is a success. Nezuko has already received it, and will be human again by the end of the night. It pains me that Muichiro cannot be here with us, but that is why I am entrusting you with this dose of the cure. Keep it safe, and use it before Kibutsuji meets his end. I know that you will be able to make Muichiro human again.

I wish you the best of luck.

Tamayo

Yuichiro’s eyes moved towards the pouch Chachamaru carried. The cure was complete? Nezuko had already received it? Amane carefully opened up the pouch, and inside was a syringe with a red liquid inside. Though it looked like blood, it carried all of Yuichiro’s hopes for his twin to live as a human once more.

Amane closed the pouch again, and Yuichiro took it and placed it in his uniform’s pocket. He made sure it fit securely and wouldn’t fall out while in battle. He would only have one use of it; he had to make it count.

“Yuichiro?”

He looked up at Amane. She was smiling again, that warm, motherly smile. “I have faith that you’ll be able to save Muichiro.”

Yuichiro felt tears come to his eyes. He wasn’t sure why, but something in her own eyes seemed deeply sad. Before he knew what he was doing, he had moved closer and wrapped his arms around her. As she returned the hug, his tears fell. “…Thank you, Lady Amane. I won’t let you down.”

“…Yuichiro, if I may, I have a favor to ask of you.” He pulled away from her embrace to listen. She reached into her robe and took out a small envelope. “I need you to go into town and deliver this for me before the tailor shop closes. Don’t worry about reporting back to me; that can wait until morning.”

“Now?” Couldn't this also wait until morning? He didn’t want to leave so soon.

“Please, it’s important. I need you to do this for me tonight.” Amane’s eyes implored him to accept. Whatever this was, it really was that important. Yuichiro knew he couldn’t refuse such a request.

“…Alright, I’ll do it.”

But though he departed from the Ubuyashiki Estate quickly, Amane’s sad eyes and grateful smile stayed with him for a long while after.

—

Yuichiro arrived at the town late into the night, and he feared that the tailor shop might already be closed. But he was in luck, and the lights were still on as it came into view. He quickly made his way into the shop and found the elderly tailor herself preparing to close for the night.

She stopped at the sight of him, a warm smile coming to her face. “Welcome! You came just in time; I was just about to close up shop. Can I help you, young man?”

Yuichiro nodded and held out the envelope. “Amane Ubuyashiki asked me to deliver this.”

“Oh, of course! Her order’s all ready; I’ll get it packed up right away.”

It only took a few minutes for the tailor to go into the back of the shop and return with two garments. Yuichiro only caught a glimpse of them as she started putting them away in a box, but that glimpse was enough.

Two haoris, one black and one pale blue, both with misty patterns.

For him and Muichiro. Amane had these made with the full belief that Muichiro would come back to them.

”Here you go, young man. Tell Lady Amane that I said hi!”

Yuichiro wordlessly accepted the box and nodded. He held it close to his chest as he exited out into the summer night air. What should he do now? Should he go back to the Ubuyashiki Estate? But Amane had told him there was no need to.

But before he could think about it anymore, he was struck by a sudden sense of alarm. A heavy feeling filled in the air, created by a familiar aura. His eyes shot up to a nearby roof, where a moonlit figure with six eyes looked down on him.

Kokushibo!

The Upper Moon turned and ran. Yuichiro almost ran right after him, but he remembered the box in his hands and quickly placed it in front of the tailor shop door before making his pursuit. It wasn’t hard for him to keep up; it was clear Kokushibo wanted him to follow. He led him out of town and into the surrounding forest. Yuichiro kept his senses open, but there was no one here but them. But then again, Kokushibo himself was more than enough; he had no need for backup.

Finally, the Upper Moon came to a stop. They weren’t too deep in the forest, but they weren’t so close to town that anyone would disturb them. Kokushibo waited as Yuichiro caught up seconds later, sliding to a halt and glaring at the demon.

“You…!” Yuichiro growled with pure venom. “What are you doing here?”

Something about Kokushibo seemed different. He didn’t exude the usual untouchable air that Yuichiro was so familiar with. But he didn’t let his guard down for even a second; he unsheathed his sword and held it tightly, waiting for an answer.

Kokushibo was silent, appearing deep in thought. Then he lowered his head and said, “I need your help.”

That was not the answer he’d been expecting; for a second, Yuichiro froze in pure shock. Then he remembered who he was facing and snapped back into a battle stance, sword pointed at the demon.

“What kind of trick are you trying to pull here?!”

“This is no trick. I require your help. You are the only one… who may be able to get through to Muichiro as he is now.”

Yuichiro gasped. The mention of his twin’s name sent his fear skyrocketing. “What are you talking about? What did you do to him?!”

Kokushibo didn’t respond at first, but Yuichiro saw something that gave him pause. The Upper Moon’s eyes were cast downward, unwilling to meet his gaze, and his fists were clenched tight to the point of drawing blood.

It was familiar to him. Muichiro had looked the same way when he was struggling with Hina’s death after Shimizu Jima. Was Upper Moon One feeling guilt?

It was then that Kokushibo finally answered. “Muichiro has… given up on surviving this fight.”

Before Yuichiro could ask what he meant, the nighttime peace was rent apart by the boom of a massive explosion.

—

Muichiro was roused from his sleep by an unpleasant sensation. He growled and reluctantly opened his eyes, but that just made the feeling worse. He couldn’t understand what was causing it. Nobody else was around in this replica of his home; it was just him here.

And then the feeling intensified into a sharp pain, and finally he knew what it was. The kanji carved into his eyes was burning. As the pain grew, his surroundings grew dark, his vision fading out.

And then the darkness was shattered by a flash of the moonlit sky. Muichiro recognized this, the feeling of looking through eyes that were not his own. The burning faded into a dull throb as visions continued to move across his mind’s eye.

The Ubuyashiki Estate, quiet and peaceful.

Hinaki and Nichika playing with their ball.

Amane knelt above the Master, unable to move from his futon, but able to acknowledge the one whose eyes Muichiro saw through.

“…So you’re here. A… pleasure… to meet you, Muzan Kibutsuji.”

Suddenly Muichiro understood what was happening. Muzan was showing him what he saw, making him watch as he killed the Master himself. Fury warred with horror, but he couldn’t look away. Even when he closed his eyes, the visions were still there.

“Tell me…” Master Kagaya breathed, “How is Muichiro? Does he still live?”

Huh? The Master was facing death right in the face, and he was worried about Muichiro? But Muichiro reminded himself it was only because he didn’t know the truth. If he did, surely he wouldn’t care.

“He is alive,” Muzan answered. “But he is one of mine now, as he was always meant to be.”

“…I see…” And then Kagaya smiled. “That is good… as long as he lives… he can be saved.”

What? What was that supposed to mean? Muichiro didn’t understand; he couldn’t be saved. Not anymore. Why was the Master saying this?

But as much as he wanted to demand an answer, Muichiro was only a spectator. He couldn’t do anything but watch as the Leader of the Demon Slayer Corps and the Demon King spoke to each other for the first and last time. They spoke of what it meant to be eternal, to be undying. The Master believed immortality was not possible for living beings to achieve. He believed that only human feelings were truly undying, persisting even after death. Muichiro clung onto every word.

Would his feelings persist too, after his death? His love for the Corps, his friends, his brother - would it all live on after him?

But Muzan soon brought their discussion to a close. “Are you done talking?”

“Yes. I never expected you to listen this long.” Master Kagaya smiled, serene and peaceful, like the Buddha himself. “Thank you… Muzan.”

There was a strange sound, and then the image of Kagaya and Amane was washed away by a brilliant white light. Muichiro screamed as fire flooded his eyes and cut his connection to Muzan off in an instant. The backlash paralyzed him, but it passed as quickly as it came. Soon the pain ceased, and he could think once again. Soon he realized what had happened.

Muzan had been preparing to kill the Master. But the Master had anticipated his attack. And with his death looming, he had launched one final strike against the Demon King. One Muichiro knew well.

An intense wave of light and heat. An explosion.

Tears filled Muichiro’s eyes. Master Kagaya, Lady Amane, Hinaki, Nichika; they were all gone. The people who had taken in him and his brother, who accepted and believed in him, who he had come to view as family… they were all dead.

And it was Muzan who was responsible.

A familiar presence appeared, and Muichiro looked up to see the shadow looking down at him. For once, it wasn’t smiling. Its expression was somber as it knelt down and pulled Muichiro into its embrace.

“Once more, you’ve lost the ones you love,” the shadow whispered. “How many more will you lose?”

Muichiro couldn’t answer. He felt the fire building inside.

“…Take action.”

Muichiro stood up, aging back to his usual appearance. Muzan’s presence was weak; something was distracting him. This was his chance. He rushed out of the house, thinking about how he was going to get out of this false forest. Nakime had teleported him in, but there must still be a way out, right? If he could-

His instincts shouted danger, and he stopped and leapt back as a bolt of lightning struck the ground where he'd just stood.

“And where are you going?”

Muichiro recognized that voice. His eyes narrowed at the sight of Kaigaku leaping from a tree to stand directly in front of him. The traitor’s eyes were marked with the kanji for ‘Upper Six’.

“What do you want?” Muichiro growled. The fire burned inside, but he kept it restrained for now.

“Me? I’m just making sure a certain Upper Moon isn’t thinking about betraying us,” Kaigaku answered with unveiled contempt. “Where are you rushing off to in such a hurry, anyway?”

“Like you need to know,” Muichiro spat back with equal disgust. “You’re only Upper Moon Six, remember? I’m your superior.”

Kaigaku’s face twisted with fury, but he calmed himself down and grinned. “You might be Upper Moon Five, but I know you can’t be trusted. You’re still on the demon slayers’ side. But why bother? You know they’ll all be dead by the end of the night.”

Muichiro glared, saying nothing.

“Ubuyashiki’s dead, don’t you know? Blew himself to smithereens, along with his family. Even he knew there was no beating Muzan, so he went and killed himself instead.”

Muichiro’s eyes widened, their glow intensifying. How dare he claim something like that? How dare he call the Master a coward? His body went rigid, but the fire was still building, and about to burst.

“This one needs to learn his place, don’t you think?” the shadow whispered in his ear. “Why don’t you let me do something about it?”

Muichiro took a step forward, his eyes meeting Kaigaku’s own. The new Upper Six stopped talking, looking nervous as he perceived a sudden change in the atmosphere. “Hey, what’s with that look? If you attack me, Muzan will punish you, you know?”

Muichiro did know. He didn’t care. He was done listening to the squeaking of prey.

“Blood Demon Art: Mist Twin Guardian.”

A flash of red leapt from his body, and suddenly Kaigaku was sliced from shoulder to hip. The demon stumbled and turned too late, seeing a cloud of red mist in a humanoid shape, a copy of Muichiro, crouched down with a sword in its hand. It stood and turned to face him, hollow eyes glaring.

Kaigaku quickly realized how bad the situation was turning. “Nakime! Get me out of here!”

But Muichiro was ready. He lunged before Kaigaku even finished speaking, grabbing a hold of him. The sound of the biwa rang and the forest disappeared, replaced with a simple hallway as Kaigaku crashed to the floor with Muichiro on top of him.

Traces of the red mist still lingered, and sparks leapt from Kaigaku to ignite them. The explosion threw Muichiro back, and Kaigaku leapt to his feet, immediately taking off down the hallway. But the blood mist gathered again, reforming as the guardian which surged forward and sliced off the Upper Six's head before he could even see it coming. Several smaller mist beasts split from the guardian's form, eager to chomp down on their prey.

But a sudden, agonizing pain in Muichiro’s eyes put a stop to that. The mist beasts and the guardian convulsed and fell apart. Kaigaku reattached his head and continued his escape, but Muichiro barely noticed; the pain had him screaming on his hands and knees and clawing at his face. Blood turned to mist that lashed out all around him without purpose. His vision flashed red with each pulse of agony.

He couldn’t take it anymore. Muichiro’s claws dug in around his eyes and squeezed, and suddenly the pain stopped, and he couldn’t see anything at all. Something wet slipped down his cheeks and through his fingers, and he became aware of an awful stinging, but it was nothing compared to what he’d just experienced.

He soon felt the familiar sensation of his regeneration starting, but Muichiro forced it to stop. He knew this was a punishment built in by Muzan, meant to keep him from disobeying or going against orders. If his eyes regenerated, the pain would only start anew.

But that was fine. He didn’t need them; he had four more.

Opening his other eyes, Muichiro prepared to go after Kaigaku. But a new sound caught his attention. Multiple sounds. The roars and growls of demons, and the shouts and screams of humans.

“The final battle begins.” Muichiro turned to see the shadow standing beside him. It still looked like Yuichiro, but the red mist surrounded it as it manifested through his Blood Demon Art. “Are you ready?”

Muichiro nodded and gathered the Devouring Mist around him, his beasts snarling hungrily within the sanguine fog. There were hundreds of demons in this castle. Hundreds of monsters. But Muichiro was the bigger monster. He had more heads and more teeth. His claws were sharper, his fangs deadlier. He would devour them all.

In their final moments, the monsters would fear him.

Chapter Text

An explosion?! But that direction is…!

Yuichiro looked in horror at the wall of flames rising in the distance. Even from here, he could tell the blast had been powerful. And there was only one place where an explosion of that intensity could have come from.

The Ubuyashiki Estate was under attack!

His horror was replaced with fury, and he turned back to the Upper Moon One.

“You! What did you-!” Suddenly he was lifted into the air, Kokushibo scooping him up and throwing him over his shoulder. “Hey! Let go of me!”

“We must hurry.” Kokushibo ignored his protests as he took off running towards the flames.

“At least carry me on your back, you bastard!” Yuichiro yelled. Being carried like a sack of rice by a demon was so humiliating; he’d held Muichiro with more dignity than this!

“Don’t talk. You’ll bite your tongue.”

Yuichiro growled and reluctantly fell silent, though he had no shortage of curses to hurl at the Upper Moon inside his head. Even at his top speed, it took time for Kokushibo to cross the distance to the Ubuyashiki Estate. But eventually Yuichiro felt him slow down, then come to a stop. He struggled again against the demon’s hold, and Kokushibo wordlessly set him down.

As soon as Yuichiro’s feet hit the ground, he turned to face the devastated site that had once been the Ubuyashiki Estate and headquarters of the Demon Slayer Corps. The fire had died down, going from an inferno to small blazes scattered about. The entire front half of the manor was just gone, its pieces strewn across the ruined courtyard, and what remained of it was charred black and exposed to the night like a gaping wound. The smell of burning flesh hung in the air; he didn’t dare look in the direction where he last saw Hinaki and Nichika, nor the room where the Master and Amane had waited.

Yuichiro suddenly felt sick to his stomach. He knew, with utmost certainty, that they were all dead. He thought about how unusually empty the manor had been, how Amane and the Master had kept their door open as if they were expecting someone to show up. And how Amane had sent him away on a seemingly trivial errand, so soon after he’d arrived, as if it was a matter of life and death…

He fought back tears and turned to Kokushibo, whose face was infuriatingly neutral as he looked upon the carnage. “What happened?!”

Kokushibo closed his eyes and exhaled before opening them again. “Lo… Muzan discovered Ubuyashiki’s location and planned to launch an attack tonight. This explosion was… likely Ubuyashiki’s response to his attack.”

Yuichiro’s breath caught in his throat. Then, they knew that Muzan would appear tonight. Amane had sent him away so he wouldn’t be caught alone and unprepared.

Kokushibo started walking towards the manor. “Come. Muzan’s presence is weaker than normal… he cannot affect me right now… this is our opportunity to get to Muichiro.”

“Huh…? Hey, wait a minute!” Yuichiro’s temper was building as he ran after him. “First of all, stop saying his name like you’re so familiar with him! And second of all, you still haven’t explained anything! What did you do to Muichiro, and why are you asking for my help to fix it?”

“I will explain, but first we must get inside.”

“Inside what?!”

“The Infinity Castle.”

Yuichiro’s heart skipped a beat. That was the place the shadow had named in his dream; so it was real after all! “What? How?”

“Nakime’s power still lingers here. It must be… there.” Kokushibo turned his head, and Yuichiro followed to see something peculiar: an open doorway embedded in the ground, untouched by the explosion. Yuichiro hurried to look inside, but beyond the doors, there was only darkness.

He remembered the door that appeared when Kokushibo kidnapped Muichiro; this had to be another entrance to the Infinity Castle. Kokushibo approached him and held out a hand. “Take my hand… we must stay close… so that we are not separated.”

Yuichiro glared; being in the Upper Moon’s presence was making him sick with restrained fury. He didn’t trust him, but he had to know what was happening to Muichiro. He took Kokushibo’s hand, and yelped as the demon lifted him onto his back and leapt into the doorway.

Yuichiro wrapped his arms tightly around Kokushibo’s neck as they fell. His eyes adjusted to the darkness, and he saw light after light flash by. Their descent seemed endless, a yawning void below with no bottom to be seen - he wondered if it even had a bottom. But then Kokushibo’s sword lashed out, catching the wall and gradually slowing their fall. He leapt down to the wall across from them, then across again, and then once more to jump through an open doorway.

Finally, Kokushibo’s feet touched solid ground, and he let Yuichiro climb off to take in their surroundings. A large pathway lit by lanterns stretched out over another open void. He could see why it was called the Infinity Castle; it had all the majesty of a castle in scale and aesthetic, and it truly seemed to go on into infinity. Walls, floors, and ceilings moved all around them, dizzying and dreamlike.

Yuichiro was briefly overwhelmed; how could a place like this even exist? Then he remembered Kokushibo was there, and he quickly composed himself. “Alright, we’re here. Now tell me what’s going on.”

He refused to move from this spot until Kokushibo explained everything. The Master was dead, something had happened to Muzan, and now Upper One was coming to him for help with his twin that he kidnapped. He needed something to start making sense, right now.

“…I made a mistake in bringing Muichiro here,” Kokushibo said after a moment of tense silence.

“No shit. What made you realize that?” Yuichiro scowled. Did the Upper Moon finally grow a conscience after holding his brother hostage for nearly a month? If he was feeling regret, he deserved every bit of it.

“He told me himself. I told you that… Muichiro has given up on surviving this fight. He fully believes that he will die tonight… and go to hell after his death.”

Yuichiro felt a chill run down his spine. He wanted to reject Kokushibo’s words, but he also knew his brother, both the good and the bad. And Muichiro had always hated being a demon. The times he’d called himself a monster, or thought himself worth less than humans; Yuichiro remembered them all.

“Tell me what you did to him.” His tone left no room for negotiation.

“…For weeks, Muzan has attempted to break Muichiro’s will… to use him as a weapon against the demon slayers. He was ruthless in his torture, but… Muichiro did not break… at least, not in the way he wanted.” Kokushibo explained. “I believe that Muichiro has… created a false version of you… to cope with his loneliness here. He talks to it… and it seems to talk back.”

Yuichiro listened, feeling a burning rage at the confirmation that Muzan had been torturing his little brother all this time. But that rage turned to dread as Kokushibo described Muichiro’s ‘false him’. The shadow was real, and Muichiro could indeed see and talk to it. His skin crawled imagining how it might have tormented Muichiro at his lowest point.

He glared up at the Upper One. “…You did this. You’ve been here all this time, and you just let this happen to him!”

“I know.” Kokushibo accepted his blame so readily. It only made Yuichiro angrier.

“Then why are you only acting now?!”

“I… tried… but I could not disobey Muzan’s orders. Even we Upper Moons… are not exempt from his wrath, should we displease him. And he is… very displeased with me.” Kokushibo looked away, his eyes narrowing, his mouth turning in a grimace. “But… that was only my excuse. The truth is… that I did not comprehend what he was truly going through.”

“So now that you’ve realized how much you screwed up, you came to me for help,” Yuichiro finished for him. Kokushibo nodded, and he growled before marching past the Upper Moon.

“Come on, let’s go. But don’t think for a second that I’ve forgiven you; I’m only working with you for Muichiro’s sake. Once he’s safe, I’ll kill you myself.”

Kokushibo didn’t respond to that; he only walked ahead of him. “…Follow me. I will take you to where he is.”

—

The battle between the demons and the demon slayers waged on in a clash of claws and steel. The mutated demons forged by Muzan had the strength of Lower Moons, but the slayers had grown as well, their training with the Hashira showing its worth. But for every demon cut down, more seemed to take their place. And each one was bigger and more beastly than the last.

One such demon batted a group of slayers aside with a single swipe of its massive claws. The lion-like beast barreled through even its own kind, its three eyes swiveling mindlessly in search of more prey. One demon slayer ran in and tried to reach its neck with a jumping slash, but its spiked tail swung around and caught his leg midair. The slayer hit the ground hard, leg bleeding and bent at a grotesque angle; he tried to move but couldn’t. The other demons kept his companions from getting close enough to help.

The slayer was helpless as the demon loomed above him. Its jaws opened up, eyes focusing on its next meal.

A flash of red sliced through the demon. For a moment, it froze, and then it collapsed, split down the middle. A humanoid shape landed in the midst of its remains, formed from a crimson mist that spread out and engulfed the demon, melting down its massive form in seconds. The hall was suddenly filled with an intense aura of bloodlust, bringing the fighting on both sides to a terrified halt.

“This feeling…” The downed slayer trembled with dread. All he could see beyond the strange misty thing was a wall of red fog. “Is this… an Upper Moon?”

The mist thing’s dark eyes looked down on him with contempt. Then it raised its sword and leapt past him to crash right in the middle of a group of demons. Its blade swung out, crimson mist cutting and swallowing them all in a single stroke.

A rumbling filled the hall; biwa chords rang out as pieces of the walls, floor, and ceiling moved discordantly, slamming against each other, trying to hit something as it darted through the mist.

Muichiro ran forward, eyes fixed on the demons ahead. The wall to his left rumbled, and he leapt back as it burst forth and smashed into the opposing side. The ceiling followed next to try and crush him, and he wrapped himself in mist before charging straight through the wall blocking his way.

On the other side, the Mist Twin Guardian cut through the hoard of demons with surgical precision, slicing limbs and heads without even touching the human slayers. Muichiro burst through the wall, shrouded in the blood red cloud, and willed the Devouring Mist forward, swallowing those demons unfortunate enough to be near him. Their screams were a cacophony that only further enticed his hunger.

One demon tried to flee; at Muichiro’s command, the mist swept in to block its path. As it turned back, he lunged, claws latching onto its face and forcing it to the ground. Through the haze, golden cat-like eyes looked up at him with pure fear.

Muichiro bared his fangs in a grin and squeezed, crushing the demon’s skull and letting the mist flow over and devour it. As he stood up, the sea of red came to a halt, rumbling threateningly. The demon slayers stood frozen, unable to even raise their swords against the overwhelming aura he radiated.

Muichiro raised his hand, and beasts within the mist reared up and roared, a single warning for them to run.

And run they did, recognizing how outmatched they were. Muichiro watched, trying to maintain control as he absorbed Muzan’s blood inside these demons. The familiar red haze edged at his vision. He waited for the slayers to get away, but a few stopped and looked back.

“Iori!”

“Iori, get up!”

Muichiro looked down, seeing a single slayer who had failed to flee. He sat on the ground, his right leg cut and bleeding heavily. Muichiro stepped forward; the Devouring Mist moved around him, feasting on the remaining demons, but his gaze was fixed only on the slayer. Iori tried to back away from the demon shrouded in mist, discernible only by the turquoise glow of his four eyes.

But as he came closer, the boy’s expression changed.

“Tokito-Sensei?”

Muichiro froze, his eyes meeting those of the downed slayer. He recognized him from the Hashira training, and it was clear Iori did, too. The raging red mist slowed and thinned, mortified realization dampening his fury.

“…” He couldn’t speak; his mouth felt dry. “I…”

The strum of a biwa echoed, and the ground beneath Muichiro’s feet shot up and crushed him against the ceiling. He coughed up blood from his smashed lungs, body pressed painfully between the two pieces of wood. Then the ceiling opened up, and the moving floor continued to push him upward and away from the injured slayer.

Iori watched him disappear into the void above with an utterly dumbfounded expression. “…What the…?”

As he moved through the castle, Muichiro felt his frustration building. Ever since he escaped his “home” in the forest, the Infinity Castle itself had turned against him, trying to keep him away from the fight. Not that it did any good; being crushed by walls and sent through random doorways had done nothing to keep him from tearing through every wretched demon he could find. Still, it was a massive hindrance to deal with. He knew Nakime was responsible; no doubt she still held a grudge over his attempt to eat her.

But once he got a hold of her…

Muichiro forced the Devouring Mist through the pillar to destroy it, but as he did, the biwa's tone summoned another one to slam into his right side. He struggled to push away from the wall and reorient himself, only for a melodic strum to bring the pillar to a stop, and yet another tower of rooms to crash into him from below. Muichiro fought the urge to scream; he was going to smash that stupid instrument to pieces!

As the tower moved up, Muichiro turned his head to see another coming down on top of him. He bared his fangs. “Blood Demon Art: Mist Twin Guardian!”

The guardian burst from his body, mist sword striking out blindingly fast to slice through the incoming structure. The tower he was pinned to pushed harmlessly through the wooden remains.

Muichiro watched as the guardian landed beside him, the red mist dispersing to reveal the shadow, still wearing his twin’s form. The fake Yuichiro grinned down at him.

“Having fun?” he teased.

“I’m going to rip that demon limb from limb and eat her entrails while she watches!” Muichiro snarled as he was finally able to stand up again.

“Ooh, I like that idea. Save it for when you actually find her, okay?” Not-Yuichiro chuckled. “Keep moving. Don’t give her a chance to focus on you.”

Muichiro nodded; the last thing he needed was to get teleported to who knows where. He noticed another tower rushing towards him and crouched low. The blood mist formed the head of a dragon as he leapt towards it, smashing through wall after wall until he burst out the other end to free fall towards a pathway leading further into the castle. Landing on the path, Muichiro heard sounds of battle nearby.

“More prey,” Not-Yuichiro landed beside him with an anticipatory glint in his teal eyes.

Muichiro felt that same hunger. It was time for the Devouring Mist to feast once again.

—

Yuichiro kept close to Kokushibo as they traversed the endless halls of the Infinity Castle. Nothing about this place made sense; the paths twisted and turned, and sometimes they traveled up or down or even upside down, which shouldn’t be possible but somehow was here. He had given up on trying to understand it, and just trusted that the Upper One would get them to where Muichiro was.

“It should be close by now,” Kokushibo told him.

“Where are we going, anyway?” Yuichiro asked. He didn’t even know how long they’d been running; it’d felt like hours, but he had no way to be sure. They hadn’t even encountered any demons to break up the monotony of constant traveling.

“I had a space prepared for Muichiro. It is far from the rest of the castle… but we should reach it soon.”

The pathway they were traveling along came to an abrupt end, and Kokushibo held out a hand. Yuichiro groaned and let him pull him onto his back before the demon jumped. They fell for a solid minute before Kokushibo landed on another pathway he hadn’t even been able to see from above. Yuichiro decided he really hated this place.

Kokushibo let him down. “This way… the space I made for Muichiro is down-”

“Don’t waste your time; he’s not there.”

Yuichiro stopped at the sound of a new, unfamiliar voice. A small grunt escaped Kokushibo, but he otherwise had no reaction as a demon walked up the same path they were heading down. The demon had pink hair and white skin marked with blue criminal tattoos, but what caught Yuichiro’s attention most was his bright yellow eyes, bearing a set of kanji.

Upper Moon Three.

The Upper Moon that killed Kyojuro.

The demon’s gaze turned to Yuichiro with mild interest. “Oh, you brought the other one too, huh?”

A burning rage sprung up from the depths of Yuichiro’s heart; his hand flew to his sword. But before he could do anything more, Kokushibo positioned himself between him and the demon. “Akaza… what do you mean… he isn’t there?”

“Exactly what I said, the kid’s not in his space. I went looking for him, and all I found was a spot of charred ground and some blood. Not his blood, though.”

“Charred ground… a lightning strike, perhaps?”

“Seems like it. Looks like our new Upper Moon Six bit off more than he could chew.”

Huh? Yuichiro blinked, not following this conversation at all. New Upper Six? Did that mean Muzan had replaced his dead Upper Moons? And a new Upper Six implied a new Five and Four. Who were they?

Kokushibo took a moment to think, and then his six eyes narrowed. “Akaza, you said you came to look for him… Why?”

Akaza didn’t answer immediately; he stayed silent, eyes narrowing as they looked between Kokushibo and Yuichiro. Finally, he sighed and turned his head in the direction he’d come from. “I couldn’t keep turning a blind eye, you know? I thought I could get him out of here while everyone was distracted. That kid’s suffered enough.” He turned back to meet Kokushibo’s gaze. “You think so too, don’t you?”

Kokushibo nodded. “I do.”

“Hmph,” Akaza grunted. “Maybe you’re not hopeless as a father, after all.”

“Huh?” Yuichiro’s head snapped towards Kokushibo so hard he got whiplash. “Father?!”

Akaza raised an eyebrow. “You didn’t tell him?”

Kokushibo didn’t answer. He kept his eyes to the ground, avoiding Yuichiro’s gaze. “Tell me what?! Hey, look at me and explain, you bastard!”

“Ugh, I’m not sticking around for this…” Akaza groaned and prepared to jump away, but Yuichiro’s voice stopped him mid-crouch.

“Where do you think you’re going? I’m not done with you!”

The Upper Three stood up straight, looking confused. “Huh? Do I know you, kid?”

Yuichiro growled. Of course he didn’t know; he probably didn’t care enough to even remember. But this was an Upper Moon; he had to keep his temper in check. He took a deep breath, but his anger still boiled beneath the surface. “No, you don’t. But I know you. On the Mugen Train, there was a Hashira named Kyojuro Rengoku who fought to protect everyone on that train. He was my friend, and you killed him.”

“Kyojuro?” Akaza repeated. And then he grinned, a gleam appearing in his eyes. “Yeah, I remember him. He was strong; it's a shame our battle turned out the way it did. But you’re a Hashira too, right? Are you as strong as him?”

Yuichiro growled; he felt a fire rising inside him, and then the burning feeling of the mark manifesting on his body. Akaza’s eyes glowed brighter, but before the situation could escalate, Kokushibo stepped in.

“Enough… you and I… do not have time to waste fighting.” He looked at Yuichiro as he spoke. Yuichiro glared back, but he soon relented, turning away to calm himself. He hated to admit it, but Kokushibo was right; finding Muichiro was what was most important right now.

Akaza seemed to back off as well, submitting to Kokushibo’s authority. “…I can’t say I know where the kid’s gone, but… you feel it too, don’t you? There’s a lot less demons in the castle, and I don’t think it’s the Hashira that are responsible. So you’d better get to him fast, before Muzan finds him first.”

With that, Akaza’s presence disappeared. Yuichiro looked back to see Kokushibo deep in thought.

“…Come. I can still locate him through our connection.” He started walking again, but Yuichiro stopped him.

“Hold on, you still haven’t answered my question. What did he mean when he called you a father?”

Kokushibo frowned. “I…”

“…You’re a Tsugikuni, aren’t you?” Yuichiro asked the question that had been in the back of his mind for two years now. Kokushibo’s eyes widened. “Yeah, I remember what you said. You said we were descendants of the Tsugikuni bloodline. So if you’re a Tsugikuni, then that means…”

He paused, waiting for Kokushibo to supply the answer he had already come to.

The demon sighed. “…You are correct. I am… was of the Tsugikuni family. My name was-”

But just as the Upper Moon was about to reveal the truth about himself, he stopped. His eyes blew wide open, glazing over as he stared straight through Yuichiro. Seconds stretched on, and Yuichiro began to feel unnerved, but just as he was considering how to rouse the demon, Kokushibo snapped back to reality. He blinked, and his six eyes narrowed.

“I know where he is. Follow me. I will… explain everything along the way.”

—

The howling of the blood mist spelled certain death for all demons in its path. Its hunger was insatiable as it fell upon them, absorbing their cells into itself in a matter of seconds, and feeding that power to its master in turn.

Muichiro didn’t want to admit it, but Muzan had indeed made him stronger. His demonic mist was more deadly than ever; none of the demons in his path could lift a claw to threaten him. Any who tried were consumed before they could even get close, and all who fled met the same fate. And with each kill, the Devouring Mist became more excited, more frenzied and harder to direct. It wanted to spread and swallow up everything, demons and humans alike.

But Muichiro refused to let that happen. The red haze clouded his vision, but he still knew a human from a demon, and no matter how much the mist cried out for blood, he wouldn’t let it touch the slayers. He gave them a chance to flee and they took it. Maybe they recognized him, or maybe all they recognized was the power of an Upper Moon. But it didn’t matter, as long as they were far away from him.

As the last of the demons in the corridor melted away in the vicious haze of red, the demon slayers ran back the way they came. Muichiro heard them cry out for the Hashira, and wondered if he might run into one of them soon. If he did, he’d have no choice but to flee. He couldn’t risk hurting them, and he couldn’t die yet, either. He still had yet to kill even one of the Upper Moons; he couldn’t die before they were all erased from this world.

A flapping of wings reached his ears, and Muichiro looked up. Through the sanguine haze, he saw a Kasugai crow flying towards him. But not just any Kasugai crow.

Muichiro gasped. “Ginko?”

“Muichiro! Is that you?” the crow in question cried out as she flew toward the red mist, heedless of its danger. Muichiro backed away, trying to hide inside the fog, but Ginko just flew around it, overjoyed to see him. “When the other crows started to talk about a red mist, I knew it had to be you! I’m so happy you’re safe! Yuichiro and I were so worried about you!”

“You were?”

“Of course! We’ve both been worried sick!” Ginko flew even closer, her wing beats faltering, and against his better judgment, Muichiro allowed the mist to thin and held out his hands for her to rest. He noticed how thin she was, her feathers lacking the sheen she was so proud of. Had she really worried for him so much that it affected her health? His heart ached with guilt.

Ginko looked up at his face, and a squawk escaped her. “Muichiro, your eyes…!”

“Don’t,” Muichiro shook his head frantically. “Don’t say anything.”

Ginko’s shock changed to concern, but she obeyed his request. A moment of silence passed between them, thankfully uninterrupted. Nakime’s attacks seemed to have stopped for the time being; was something else distracting her? But thinking of that made Muichiro realize that Ginko could give him valuable information about the battle.

“Ginko, what are the statuses on the Upper Moons?”

Ginko seemed surprised by the question, but soon she puffed herself up and stood tall to deliver her report. “ Two Upper Moons have been killed so far! Upper Moon Six was killed by Zenitsu, and Upper Moon Two was killed by Shinobu, Kanao, and Inosuke!”

Muichiro’s eyes went wide. He wasn’t surprised by Kaigaku’s death; the traitor wasn’t truly on the level of the Upper Moons, and he was too arrogant for his own good. That he lost to a single slayer, one who wasn’t even a Hashira, was so fitting that Muichiro wasn’t even upset that he hadn’t been the one to kill him.

But Upper Moon Two, Douma; he was already dead? He still saw red whenever he thought of the rainbow-eyed demon and what he’d tried to do to him. A part of him had anticipated making Douma feel fear for the first time before his end. But he was already dead, killed in the time Muichiro had spent being stalled by Nakime.

“Muichiro?” Ginko must have noticed his agitation. He forced the anger down; he needed to hear more.

“I’m fine. Go on.”

Ginko nodded. “Upper Moon Four is currently being fought by Mitsuri and Obanai! And we have not yet sighted Upper Moons Five, Three, or One!”

Muichiro felt a brief panic, but he forced himself to appear calm as he quickly shook his head. “You don’t have to worry about the Upper Five; I already took care of that one.”

It was technically not a lie. Ginko accepted his words without hesitation. “You did? That’s amazing! Just what I’d expect from you, Muichiro!”

Muichiro nodded and tried to refocus before the guilt could eat him alive. So Nakime was in a battle with two Hashira; that explained why she stopped attacking him. As much as he wanted to kill her himself, he had faith that Mitsuri and Obanai could defeat her. And while it was strange that Akaza had yet to be spotted, he knew it was only a matter of time before the battle-hungry demon sought out one of the Hashira to fight. So that left only Upper Moon One, Kokushibo, unaccounted for.

“What about the other Hashira?” he asked.

“What about my brother?” went unsaid.

Ginko’s cheerful mood sank like a stone. She bowed her head, and Muichiro feared the worst. “Shinobu is dead; she was killed in the battle against Upper Moon Two.”

Muichiro felt like he’d had the breath ripped from his lungs. For a moment, he pictured Shinobu’s smiling face; it brought tears to the corners of his eyes, but they didn’t fall. His heart squeezed, grief and rage mixing painfully inside him.

One after another, the people he cared about were dying.

Ginko went on somberly. “The other Hashira are alive but scattered. But Yuichiro wasn’t brought here with them. I don’t know where he is.”

Muichiro was still processing Shinobu’s death, and hearing that only sent him into a greater panic. If Yuichiro hadn’t come with the other Hashira, did that mean he might not be here at all? But there was no way Yuichiro wouldn’t come for him, right? His fear was building, but he couldn’t let Ginko see it. He closed his eyes and tried to push it down deep into the fog, to force himself to stay calm. It was starting to work, the fear and sorrow fading in the mist.

But the sound of heavy footsteps made him stop; he opened his eyes again. More demons? No, this felt different, more like-

“Oh, that’s right! I just was with Gyomei!” Ginko yelled, hopping into the air and flapping her wings excitedly. “He must have followed me!”

“Himejima’s here?!” Muichiro’s half-buried panic surged up with renewed fervor. He couldn’t face Gyomei, not now! His cells itched to split apart and flee, so much so that he heard a certain sound just a second too late.

The twang of a biwa echoed, and suddenly a wall was moving towards him and his crow.

“Ginko!” Muichiro leapt forward, grabbing the startled crow and holding her to his chest as he put himself between her and the wall. It slammed into him a split second later, heading straight for the opposite side. Muichiro’s heart stopped; they were going to be crushed. But while his body would heal, Ginko’s would not.

He closed his eyes and wrapped the Devouring Mist around them both in a desperate attempt to shield her. But then he heard a rapid series of slashes, and the wall he was pinned to burst out into open air. Muichiro opened his eyes, and he looked up to see Not-Yuichiro standing on top of the now-airborne pillar of rooms, smiling that ever-infuriating grin.

“Where would you be without me?”

“Oh, shut up!” Muichiro dug his claws not holding Ginko into the wall, and a huge mass of red mist filled each room inside before bursting out to destroy the whole structure in an instant. Without anything to push him along, Muichiro started to fall. He saw ground below, and his lower body turned to mist, bringing his descent to a gradual halt. He held Ginko close as he slowly floated to the ground.

Muichiro looked around, taking in wooden pillars in a vast space he’d seen many times before. It was Kokushibo’s training grounds; what luck for him to have ended up here, of all places. His feet reformed on the ground, and he looked down at the crow sheltered in his arms. “Ginko, are you okay?”

Ginko shook her head and stood up, trying to hide how scared she was. “Of course, thanks to you, Muichiro!”

But Muichiro didn’t miss the way her right wing was kept awkwardly tucked against her body. His anger returned, so hot that he thought it would burn him up inside. Ginko wasn’t a threat to anyone. She wasn’t a demon slayer; she was just an animal. And yet Nakime had tried to kill her, for no reason other than to hurt him.

“Muichiro?! Muichiro, calm down! I’m fine! It's not that bad, really!” Ginko cried, flapping her good wing frantically. Muichiro blinked and saw the Devouring Mist spreading out, roiling violently in response to his emotions. He tried to calm himself by extending his senses, feeling for any other life nearby. But it was just them.

Muichiro growled; he was getting nowhere like this. He needed to find the remaining Upper Moons and stop them before they could hurt anyone else. But how?

“That's simple: use your blood connection.”

Muichiro blinked, he turned to face the shadow. What?

“You heard me. You don’t have to search for Upper Moon One at all; you two have a blood connection. Use that to find him.”

Muichiro was stunned; it really was a simple, obvious idea. Why hadn’t he thought of it himself? Probably because he had no idea how to actually use that connection. He’d only done it once, by complete accident. But he had to try.

He felt the gazes of both Ginko and his fake twin as he closed his eyes and looked inside himself. He focused on feeling the blood running through his veins, the same blood he shared with Kokushibo. He willed it to show him what the Upper Moon was seeing. But his vision remained frustratingly dark, his memories and feelings his own.

“It’s not working…” he growled aloud.

“Try again. Or go back to searching aimlessly while getting crushed by walls the whole time. It’s your choice.” Not-Yuichiro said unhelpfully.

Muichiro growled louder. What he wouldn’t give to have the real Yuichiro to give him advice instead of this condescending-

The darkness behind his eyes exploded into light, and suddenly he was looking at Yuichiro. The real Yuichiro, wearing only his Hashira uniform without his haori, his smell and aura undeniably human. He was looking up at Muichiro, confusion and slight worry in his gaze.

No, Yuichiro wasn’t looking up at him. He was looking up at Kokushibo; Muichiro was seeing through Kokushibo’s eyes. The location they were in was undoubtedly the Infinity Castle; Yuichiro had come for him after all!

But he wasn’t able to look for long. He felt a strange sensation, as if a new pair of eyes had settled upon him. It was a familiar gaze, tinged with surprise, and Muichiro remembered that this blood connection went both ways.

And then suddenly that connection was cut off. His eyes snapped open. The vision of Yuichiro disappeared, replaced with the training arena and Ginko’s concerned face.

“Muichiro?”

Muichiro didn’t answer; he blinked, trying to make sense of what he saw. Kokushibo was in the Infinity Castle with his twin. But why? He hadn’t sensed any hostility, nor had Yuichiro looked threatened. So if they weren’t fighting, did that mean they were working together? What was Kokushibo trying to do?

“Oh, is that not obvious?” Not-Yuichiro was suddenly right in front of him. But though he was smiling, his gaze was cold. “He knows what you’re planning, and he’s certainly told your big brother, too. This ridiculous self-sacrificial scheme of yours, they’re going to try and stop it.”

Muichiro felt a pit open up in his stomach; a chill swept over him. Then it passed, and the fire inside burned hotter; he wouldn’t let that happen. The red haze creeping at the edge of his vision spread further.

Not-Yuichiro continued. “But now you know where he is. And more importantly, he knows where you are.”

Muichiro nodded. In his hands, Ginko’s concern was growing by the second. “Muichiro? Are you okay?”

“…Ginko, can you fly?”

“Yes, of course!” Ginko spread her wings with a poorly disguised wince, but when she took to the air, she was able to maintain her flight.

“Good. Get as far away from here as you can. Upper Moon One is coming, and I have to stop him.”

“Huh? All by yourself?” Ginko looked shocked.

“It’s okay. I can handle it.” Muichiro’s expression was deathly serious. “This is something I have to do.”

“…Okay! I trust you, Muichiro!” Ginko flew off, and Muichiro turned to watch her go until she was a black speck in the distance.

He heard the fake Yuichiro’s voice chuckle behind him. “She trusts you, she says. As if you haven’t already betrayed that trust.”

Muichiro’s heart clenched, but he pushed the unpleasant feeling down into the fog. He couldn’t think about that right now; he had a fight to prepare for. His former teacher was coming, and he would almost certainly have his twin in tow.

“You don’t have to worry about that,” Not-Yuichiro grinned. “I’ll handle him.”

Muichiro glared. He didn’t trust him, but… he had no choice. “…Just don’t hurt him.”

For just a moment, the false Yuichiro frowned. But then it was gone, the grin back on his face. “I wouldn’t dream of it…”

Something about the way he said that made Muichiro angry, but then again, everything the shadow said made him angry. He couldn’t figure out if it was with him or against him.

Still, Muichiro had no option but to rely on it. He had a mission to complete, and he couldn’t let Yuichiro interfere until the time was right.

He lifted his arms, and white mist began to fill the arena. Whatever happened tonight, he promised that this place would be the Upper Moon One’s grave.

—

Michikatsu Tsugikuni.

That was Upper Moon One’s true name, his name when he had been human.

He’d been a demon slayer from the Sengoku Era. He was the creator of Moon Breathing, and the older twin brother of Yoriichi Tsugikuni, the creator of Sun Breathing. And he was a traitor who became a demon, who almost wiped out the Demon Slayer Corps, all in the name of becoming the strongest swordsman of all.

Yuichiro listened to his story without interruption, waiting for him to explain everything. But though he held his tongue, his disgust with the Upper Moon only grew. He was truly a monster, a being who killed countless humans over hundreds of years, for so petty a reason as being jealous of his more talented twin brother.

It was something Yuichiro couldn’t even fathom, much less try to empathize with. He knew Muichiro was more talented with the sword than him; that was just a fact. And maybe he did feel envious, from time to time. But to be so envious that he’d give up his humanity and become a monster to be stronger than him? Never.

“There’s one thing I still don’t understand,” Yuichiro said once Kokushibo fell silent, his story finished. “You had a family when you were human, and you gave that up. You had a twin, and you betrayed him. You haven’t cared about anyone for hundreds of years, have you? So what changed? Why do you care so much about Muichiro now?”

“You are… not wrong. After Yoriichi’s death… I cast aside all human emotions… in the pursuit of strength. I believed there was nothing human left in me. But Muichiro… showed me that wasn’t true. He... awakened something in me… that I buried long ago.”

So Muichiro had cracked the stone-cold heart of Upper Moon One. Yuichiro could almost laugh if the situation wasn't so dire. But he also felt pride and vindication. His little brother, who hung onto his humanity even as a demon, had reached the humanity in the very demon who transformed him. The strongest demon besides the Demon King himself. It must have made Muzan furious.

Kokushibo went on. “I have not felt love in four hundred years. And yet… over these past three years… I have watched over you two brothers. I have seen you love and support each other unconditionally. I saw… what Yoriichi and I could have been. What I… should have been.”

Yuichiro glared. Taking so long to realize that, he really was a sorry excuse for an older brother. “And what about your loyalty to Muzan?”

“I have already dishonored myself in his eyes. But that blood-stained loyalty… was worth nothing from the very beginning. Now, I only wish to protect… the family that I have left.”

Yuichiro scoffed. He’d accepted that this monster was his ancestor. It made him sick to imagine that tainted blood in his veins, but it was the truth. But he was delusional if he thought Yuichiro would ever see him the way he saw his parents or the Ubuyashikis. “You may be our ancestor, but you’re not our family.”

“…I understand.” Kokushibo’s voice betrayed nothing of how he truly felt. “I do not expect… nor do I desire… your forgiveness. All that I ask… is that you give me a chance to save Muichiro.”

His earnest plea gave Yuichiro pause; he never expected such vulnerability from the Upper One. He was right that he wouldn’t forgive him, but for Muichiro’s sake, he could put aside his hatred, just this once.

“…We’ll save him, no matter what.”

Kokushibo nodded, and they kept running. But within minutes, he slowed to a stop, and Yuichiro saw why a second later. A thick cloud of white mist filled the hallway in front of them, completely obscuring what laid beyond. Kokushibo narrowed his eyes and placed a hand on his sword’s hilt.

“Hey, you’re not planning on fighting him, right?” Yuichiro balked. While he would fight if he had to, raising his sword against his twin was his absolute last resort.

“I do not wish it, but… I fear it may be inevitable,” Kokushibo answered gravely. “Stay alert.”

He stepped into the mist, and Yuichiro hurried after. He kept his other senses on alert to make up for his limited vision. Now that they were inside the mist, Muichiro would know they were here. But the fog was cold on his skin, no trace of his brother's usual warmth present.

Soon, they entered into a wide open space filled with wooden pillars stretching high into the air. The mist hung heavy and ominous here. Kokushibo continued to cautiously move forward, and Yuichiro stepped as far as he could while keeping him in sight. He listened, but all was quiet.

Something unexplainable tugged at the edges of Yuichiro’s senses. And then suddenly the mist moved, honing in on Kokushibo and engulfing him in a twisting, howling whirlwind. A second later, the white mist turned blood red, and the howling grew louder.

Yuichiro stumbled back and drew his sword, raising it towards the twister. “Mist Breathing-”

But Kokushibo didn’t need his help. The twister expanded, then burst as several glowing crescents tore it apart. The Upper Moon lowered his sword and looked straight ahead. The red mist rumbled as it pulled away and hovered ominously.

The sight of it sent chills down Yuichiro’s spine. He’d never seen it this vividly red before, and the smell of blood was overwhelming. Muichiro usually didn’t eat more than a handful of demons in one night; it was clear that this time, he’d eaten many, many more.

Light footsteps echoed through the arena, heralding a powerful demonic aura. Four turquoise lights came to life within the crimson haze; the mist withdrew, coming to a halt behind its master like a barely-restrained beast.

Yuichiro’s breath left him; he felt something like a stab to his heart. “Muichiro…”

His little brother stood before him, clad in the haori given as a sign of their eternal promise, now reduced to blackened tatters. His demon crest was on full display, extending all the way down to his sharpened claws. Four of his eyes, the top and bottom pairs, glowed bright and dangerous, slit pupils fixed on them both.

But his middle pair of eyes, his natural eyes; Yuichiro couldn’t see them. The red mist flowed over them, hiding them from sight. Tears of blood marred his face.

Muichiro spoke, his voice cold and hollow.

“So, you’ve come.”

Chapter Text

“Muichiro…” Yuichiro gulped. He couldn’t understand this maelstrom of emotions inside him. He felt nervous, worried, but also relieved just to see Muichiro, no matter his condition. He sheathed his sword and stepped forward slowly, knowing better than to move too quickly. “I’m so glad… I’m so glad you’re alive!”

Muichiro’s stoic facade cracked ever so slightly; his mouth curved downward and his eyes softened. “Nii-san…”

“…I’m sorry. I’m so sorry I haven’t been here for you.” Yuichiro held back tears. “But it’s okay now. It’s going to be okay.” He took another step, but Muichiro stepped back.

“Don’t get any closer. Why are you with him?”

“Huh? Oh…” Yuichiro glanced back at Kokushibo. “That’s... hard to explain. But we’re here to help.”

“Help? He’s the one who brought me here.”

“I know, and I haven’t forgiven him for that. But he’s on our side now. We’re going to get you out of this horrible place.”

“…You can’t.” Muichiro shook his head. “I can’t leave.”

“What? Why not?”

“There are things I still have to do here.” Muichiro’s voice was unnaturally calm, but the blood mist writhed, betraying the true anger behind his mask. “Every demon in this castle, they all have to die. Every last one. I won’t stop until they’re all dead.”

“Muichiro…” Yuichiro tried to think. The color of the blood mist spoke to the power of the demons he’d eaten, the amount of Muzan’s blood he’d absorbed. Most likely, Muichiro wasn’t in a reasonable state of mind. He had to tread carefully.

Kokushibo stepped forward. “Douma and Kaigaku are dead. Nakime and Akaza are in battle against the demon slayers. And you have killed… nearly all of the demons here. You do not need to keep fighting.”

Muichiro’s gaze shifted towards the Upper Moon. His eyes stared coldly, and then he bared his teeth in a joyless smile. “No, I do. Because you’re still alive. I told you, every demon has to die.”

“Including you?” Kokushibo asked. Yuichiro felt his heart drop.

Muichiro’s smile fell. He didn’t answer, but that was answer enough. His heartbeat quickening, Yuichiro placed himself between the two demons. Muichiro stiffened. “What are you doing?”

“What am I doing?!” Yuichiro repeated incredulously. “I came here to save you! To bring you home! And now you’re telling me you want to die here on some suicide mission?!”

Muichiro flinched, his mask cracking again. “…It’s the only way.”

“Only way to what? What did Muzan do to you?” As he spoke, a horrifying possibility hit him. “Did he… make you eat people?”

Muichiro’s eyes blew wide open, the first clear emotion he’d shown; the look in his eyes was haunted. He shook his head frantically. “N-No, he didn’t!”

“Then what? Mui, talk to me!”

But he refused. Yuichiro tried to get closer, making himself as non-threatening as possible.

“Come on, Muichiro. Let's go home.” He reached towards his pocket. “We have the-”

The jaws of the Devouring Mist snapped down inches from his face. Kokushibo grabbed his collar and pulled him back; Yuichiro was too stunned to resist.

Muichiro trembled, the mist starting to whirl around him. “Enough. I have to do this. Every demon here has to die tonight. Muzan, the Upper Moons… and me.” A red mist sword formed in his hand. “But I won’t die before they do.”

“Muichi-!”

“I don’t want to hurt you, Yui. But you won’t stop me.” The mist rumbled and the beasts within reared their heads, glaring down the Mist Hashira and the Upper Moon One. “So get out of my way.”

For a long moment, Yuichiro could only stare. And then, slowly, he raised his shaking hand to grip the hilt of his sword. “Don’t do this, Mui.”

Muichiro’s composure slipped, a single sob escaping him. Then he closed his eyes, the red mist settling briefly. When he opened them again, they were focused and devoid of all hesitation.

“I’m sorry.” The blood mist whirled around him, hiding all but the blazing light of his eyes. “Blood Demon Art: Mist Twin Guardian.”

The mist leapt forward, taking a familiar shape. Yuichiro gasped, and he jumped back to dodge a blow from a misty sword.

“You again…!” Yuichiro growled and drew his own blade, glaring at the shadow taking his form within the mist. Its hollow eyes narrowed, and it lunged forward, driving Yuichiro further back.

Kokushibo turned to help him, only to be forced to move as the Devouring Mist roared and crashed down where he’d stood. It chased after him, filling the air, not giving him space to breathe that wasn’t touched by its burning sanguine haze.

From the mist, a dragon charged forth. Kokushibo swung his blade, but it leapt into the air and descended with jaws opened wide.

“Moon Breathing, Second Form: Pearl Flower Moongazing.”

A swarm of crescents flew to meet it; the two attacks collided and destroyed each other, but from the remnants of the dragon’s head, a shape cloaked in red emerged. Muichiro’s mist blade swung towards Kokushibo’s neck, and the Upper Moon narrowly dodged in time. But as Muichiro landed, he swung again, the sword releasing a wave of red mist. It sliced through the tip of Kokushibo’s blade, sending it flying away, and kept going to cut deep into his torso.

But despite the injury, the Upper One’s focus did not waver. His wound was already healing as Muichiro lunged, and he met his descendant in a deadly dance of blades. They traded blows back and forth, almost as if they were just sparring, but the all-consuming rage in Muichiro’s eyes proved that this was no mock fight. It promised that one of them would not leave this battle alive.

As the two demons fought within the mist, Yuichiro was entrapped in a battle of his own. The guardian, as Muichiro had called it, blocked his every attempt to get back to them. Its sword swung out eight times, forcing him to dodge, but it continued to pursue him, arc after sweeping arc of burning red mist driving him further from the other fight.

Yuichiro struck back after ducking beneath another swing. But his sword slashed uselessly through the guardian's body. Of course; it was only mist, with no solid form of its own. And yet, that demonic fog would have no issue hurting him if he got too careless.

The guardian almost seemed amused by the futile attempt to hurt it. It lifted a finger in a wagging motion, eyes quirking upward. Yuichiro felt his temper rising; that damned shadow was taunting him again, mocking his inability to protect Muichiro.

“Oh, you can just fuck off! Mist Breathing, Third Form: Scattering Mist Splash!”

Yuichiro swung his sword up, and the guardian looked shocked for a split second before its form was blown apart by the force of the technique. Yuichiro smirked; he might not be able to attack it directly, but it was still just mist in the end. His way now clear, the Hashira rushed towards his brother and ancestor.

“Muichiro!”

Two of his twin’s eyes glanced his way. Before Yuichiro could get any closer, the red mist swept in between them, blocking his path. Two mist beasts burst forth, and he backstepped away from their sweeping strikes. More fog formed to crowd him out and restrict his movements.

The guardian reformed in between the two beasts, directly between Yuichiro and his brother. Narrowed eyes conveyed its anger. The message was clear: it would not let him interfere in this fight.

Yuichiro growled and gripped his sword tighter. If the shadow thought it could stop him, then he would show it just how wrong it was. He breathed in deep, feeling the power of the mark, and raised his blade.

“Mist Breathing, Third Form…!”

—

The red mist burned against Kokushibo’s skin; even the slightest brush was painful in a way he’d never experienced before. Rage and hatred given form, it was hostile to his very existence. Any lesser demon would have melted in the haze; only his regeneration as an Upper Moon kept him whole and alive.

Kokushibo did not try to block Muichiro’s attacks; the brilliant crimson color and overpowering smell of blood told him all he needed to know of the power the mist held. He could not afford to be struck directly.

“Moon Breathing, First Form: Dark Moon, Evening Palace!”

Kokushibo recognized Muichiro’s form, and responded with the same technique. Their blades clashed, but Kokushibo was bigger and stronger, and his crescents cut through their crimson counterparts. One slashed across Muichiro’s face, and he jumped back.

“You will find… that my skill greatly exceeds your own, my student,” Kokushibo told him. As prodigious as Muichiro was, the Upper One had had four hundred years to perfect his Moon Breathing techniques.

Muichiro glared and continued his assault. Kokushibo was able to handle his sword techniques with minimal trouble; the problem lied in the red mist. Each attack spread the mist further, filling the arena with its haze. It clung to him, slowing his regeneration and stiffening his movements. Even his techniques could not dispel it completely.

“Moon Breathing, Fifth Form: Moon Spirit Calamitous Eddy! Devour!”

And even if Muichiro couldn’t match him in Moon Breathing, he was more than adaptable enough to make up for it. Muichiro launched a series of layered slashes, waves of mist accompanying the crescents and extending the attack’s already wide range. Kokushibo wasn’t able to dodge all of it; he landed on his feet, covered in shallow but bloody cuts.

The red mist returned to Muichiro, and he hissed in discomfort before attacking again. As they fought, Kokushibo noticed that despite his regenerative abilities, Muichiro seemed averse to getting hit himself. But he could guess why, eyes moving to the ruined haori the younger demon still wore.

“Do you hate me… Muichiro?” Kokushibo asked.

Muichiro’s assault slowed. “For what?”

“For everything. For transforming you into a demon… for bringing you here… for not saving you.”

Muichiro blinked; he abandoned his battle stance to stand straight, his expression one of hurt. “No. I don’t hate you.” His eyes narrowed, as if he were upset with himself. “But I am angry.”

“I see… and will killing me appease your anger?” Kokushibo asked. “Will my death… give you the peace you need to keep living?”

For a moment, the mist stilled as Muichiro seriously considered that question. His hands gripping his sword shook. But then they stopped, an unnatural calm descending over him once more. “…No, it won’t.”

Kokushibo nodded. He had expected that answer, but it didn’t stop his heart from squeezing tight in his chest. Human emotions were certainly troublesome. But amidst the pain, he felt a spark ignite. A new determination, to save this child who believed he didn’t deserve to be saved.

“…Very well. Moon Breathing, Sixth Form: Perpetual Night, Lonely Moon - Incessant.”

Muichiro gasped, and he barely leapt back in time as multiple slashes cut through his mist. But he couldn’t fully avoid the smaller crescents; as his feet touched the ground, he looked down in horror at the cuts across his body, staining his twin’s black haori red.

Whatever calm he forced on himself shattered instantly. The blood mist roared back to life, his turquoise eyes blazing with fury.

Kokushibo regretted causing him more pain. But the time for talk had long passed; all he could do now was act.

“You will not die here...” Kokushibo readied his blade. “There is… no peace at the end of this path.”

Muichiro answered with a scream, and the Devouring Mist lunged forth.

—

The guardian leapt into the air, sword swinging in the motions of Mist Breathing’s sixth form. Yuichiro backstepped the slashes, then weaved between the two mist beasts attacking from below.

Trying to fight an enemy he couldn’t hit was a new, infuriating experience. His third form could scatter the guardian and its beasts, but they would always return within seconds. The shadow hadn’t said a word - maybe it couldn’t speak in this form? - but its smug mockery was present every time it obstructed him from getting close to Muichiro. But he heard his twin’s enraged scream across the battlefield, and he knew he couldn’t waste time fighting this imposter.

Yuichiro used the third form to dispel the guardian, then dodged a strike from a beast before using the same form again. It was the only attack he had that was even slightly effective; was this how it felt to be Agatsuma, being limited to one form only? No wonder he was always screaming and crying.

The guardian and its beast reformed, and all three attacked from different directions. Well, if the blonde crybaby could use the same form multiple times in a row and call it a new technique, so could he.

“Mist Breathing, Third Form: Scattering Mist Splash, Thricefold!”

Yuichiro unleashed three arcing swings one after the other, taking out the two mist beasts before scattering the guardian once more. But it only bought him a few seconds before they started to reform, the fog closing back in to isolate him.

Yuichiro held back a curse; he was getting nowhere! Their attacks weren’t even hard to dodge; they were slow and predictable, but with all three pressing him, he couldn’t find any openings to get past. It was like they weren’t really trying to hurt him-

Realization struck. The guardian and its beasts were made from Muichiro’s Blood Demon Art; they were extensions of his will. And even in his current mindset, Muichiro hadn’t wanted to fight him. The guardian’s purpose wasn’t to defeat Yuichiro, but to keep him from getting in the way of killing Upper Moon One.

Which meant…

Yuichiro smirked. “I’ve got you all figured out now…!”

The shadow blinked, looking confused. Its assault ceased.

“Muichiro doesn’t want you to hurt me. In fact, I bet he ordered you not to hurt me, right? He only wants you to keep me away. But this mist is dangerous; even touching it could be deadly. You see what I’m getting at, don’t you?”

The shadow’s misty form shook; it looked angry. Yuichiro’s smirk grew. “Yeah, I’ve figured it out. You can put on a show all you want, but you can’t actually disobey him. And that means that you can’t even touch me!”

His taunting worked; the shadow shrieked in fury. The mist beasts roared and lunged, but Yuichiro made no move to dodge them. He watched, unflinching, as their jaws snapped down inches from his face.

Yuichiro grinned. “Thought so.”

His sword scattered the beasts again, and he crouched low.

“Mist Breathing, Fourth Form: Shifting Flow Slash!”

He shot straight towards the guardian; it flinched back, then burst apart as his sword cut through it. But Yuichiro sprang to his feet and kept going towards the sounds of Muichiro and Kokushibo fighting in the mist. The red fog parted around him; just as he suspected, it was forbidden to touch him, to harm him at all.

Soon, he saw his brother and his ancestor locked in combat. But as he rushed to engage, two gunshots rang out. Kokushibo flinched as two bullets struck him in the back. Yuichiro slid to a halt and turned to see Genya standing halfway behind a pillar, his gun pointed at the Upper Moon. His eyes were red and yellow, resembling Kokushibo’s, and prominent fangs filled his mouth. “Go! Now’s your chance!”

Yuichiro suddenly understood. Genya only saw him and Muichiro in battle with Upper Moon One; he had the entirely wrong idea about the situation at hand. “Wait, he’s not-!”

His eyes darted between the two, and he stopped. Two gnarled trees were growing from the bullet wounds in Kokushibo’s body, twisting around him and restricting his movements. He struggled against their bindings, but couldn’t seem to break them as they only grew larger. Muichiro looked surprised, before his lips turned up in a fanged grin.

A second mist sword formed in his other hand, and he cut through Kokushibo’s legs, bringing him to his knees. Even now, he towered over the boy, but he couldn’t lift his sword to block or attack. Muichiro raised both blades towards his neck.

“Damn it!” There wasn’t time to think; Yuichiro dove in as fast as he could. As Muichiro’s blades came down, Yuichiro slid in between them, his sword blocking his twin’s own.

Muichiro paled at the sight of him, but his anger quickly returned. “Get out of my way!”

“Make me!” Yuichiro yelled.

Unfortunately for him, Muichiro took him up on his challenge. The mist swords disappeared, and his hands shot out to grab hold of his blade and hilt, uncaring of the sharp edge cutting into his palm. He yanked on it hard, trying to pull it away, and Yuichiro fought to maintain his grip. Only the mark’s power kept his feet firmly on the ground and the sword in his grasp.

But then red mist leaked from Muichiro’s hands, and Yuichiro panicked as he saw the hilt’s fabric fraying. While the metal blade seemed to be resistant to the mist, the hilt definitely wasn’t. The fog writhed around Muichiro, crimson jaws and teeth coming dangerously close to his twin’s face. The hilt began to warp, and then-

“Wind Breathing, First Form: Dust Whirlwind Cutter!”

—

Muichiro felt it before he saw it, something cutting through the mist. And then he felt the sharp sting of wind slash through his arms, severing his grip on his brother’s sword.

Both he and Yuichiro looked up to see Sanemi Shinazugawa appear above them, lashing out with a spinning kick that Muichiro jumped backward to avoid. Yuichiro fell back as well, stopped only by Kokushibo’s hand steadying him. Sanemi dropped in front of them, briefly looking back at the two with narrowed eyes, before he looked forward again. He pointed his blade at Muichiro and glared.

“So, this is what Muzan’s done to you, huh, Tokito?” Shinazugawa growled. “Turned you against your own brother?”

Muichiro glared back; that disappointed tone, like he was a child doing something wrong, made his blood boil. Red clouded his vision.

“Shut up,” he hissed, reforming his sword. “You don’t… you don’t know anything!”

He leapt forward, and Sanemi hesitated a second before moving to meet him.

“Wait!” Yuichiro’s cry went unheard. The tips of their blades clashed, Muichiro jumping high while Sanemi slid low; he pushed to knock the sword from Sanemi’s grip, but the Wind Hashira held tight. Muichiro flipped over him and swung out again.

The sound of a gunshot rang out. Muichiro moved his head to the side, the bullet missing him by a hair’s breadth.

“Aniki!” Muichiro turned to see Genya standing at the edge of his mist.

“Genya?” Sanemi sounded surprised. “What are you doing here?! Get back!”

Muichiro saw movement in the corner of his eye; the bullet that had missed him was coming back. How-

The guardian emerged from the mist; in a flash of red, it split the bullet in two, before turning its attention to Genya. Then just as quickly, it moved through the fog and appeared in front of him, before its sword sliced through his right hand. Genya's gun clattered to the ground as he stumbled back, shouting in pain and clutching his bleeding stump.

Muichiro’s eyes widened in horror. “Wait, you’re not supposed to-!”

But a yell from Sanemi cut him off; he leapt back, the Wind Hashira’s sword cutting across his chest and drawing a spray of blood. “Don’t you dare touch my brother!”

The pain brought the red haze surging back. Muichiro’s spilled blood bubbled up into mist that lashed out at Sanemi, giving Muichiro time to distance himself. But Shinazugawa simply scattered the mist with a technique and attacked again; Muichiro growled and prepared to counter.

Until Yuichiro leapt in between them, his back to Muichiro as his blade parried Sanemi’s own. The Wind Hashira backed away, a furious look on his face. “The hell are you doing, Tokito?!”

But Yuichiro ignored his question, turning to Muichiro instead. “Muichiro, stop this! These are our friends; what reason do you have to fight them?!”

“Me…?” The question shocked Muichiro, but that shock soon turned to anger. How dare Yuichiro blame him for this? How could he still not understand?! “What about you?! I’m trying to kill the Upper Moon; you’re the ones defending him!”

“There’s no reason to fight him anymore!” Yuichiro refuted. “Upper Moon One is on our side now; he’s not a threat!”

“What? Tokito, are you crazy?!” Sanemi looked at him in disbelief, but his question went ignored, both twins glaring at the other.

“So what?! After everything he’s done, why should he be forgiven now?!” Muichiro snapped.

“That’s not what’s happening! He wants to help you, Muichiro! We all do!”

“If you really want to help me, then get out of my way!” The red mist roared in time with his scream. Yuichiro grimaced and Sanemi readied his blade again, watching Muichiro carefully. But his focus shifted as Kokushibo stepped forward.

“Yuichiro, that is enough.” Kokushibo tore away the trees binding him. “This plan is not working… leave now. I will fight him alone.”

“Shut up!” Yuichiro snapped. “Like hell I’m doing that! We’re saving him, no matter what!”

Muichiro shook; his claws clenched into fists. “…I don’t want to hurt you, but if you won’t leave… then I’ll make you.”

The red mist swept in between them and formed into the guardian’s familiar shape, mist sword pointed at Yuichiro’s chest. But Yuichiro didn’t look intimidated, glaring darkly at the copy.

“We both know you won’t let that thing hurt me, Muichiro.”

Muichiro growled, because as much as he needed to make good on his threat, Yuichiro was right.

“Hmph, pathetic.”

His eyes snapped to the guardian- no, the shadow. “What?”

The shadow scoffed. “After all your talk of doing what needs to be done, you’re still limited by human sentiment. Your plan is falling apart at the seams.”

“Shut up! You said you’d keep Yui away!”

“Mui?” Yuichiro called his name, sounding confused and worried.

“Unfortunately, there isn’t much I can do when I’m not allowed to even touch him. But, if you gave me a little more freedom…”

“Like hell I will! You already hurt Genya!”

“Your friend’s hand will regenerate. And don’t forget, you were the one who summoned me to protect you. But I can’t do that without using force. These humans must realize that they are putting themselves in danger by opposing you.”

Muichiro glared, but he couldn’t refute its words; he knew it was right. He knew he was limiting himself by refusing to hurt humans. He couldn’t trust the shadow, but what else could he do? Yuichiro and Sanemi, they wouldn’t listen!

“Muichiro? What is that thing saying to you?” Yuichiro sounded panicked now. It only added to Muichiro’s building anxiety. His body shook; he felt like he was going to burst.

“Tokito, get away from him,” Sanemi warned. He grabbed his sleeve, but Yuichiro pulled away, refusing to move.

“Let me help you,” the shadow’s voice drowned them out. It turned to Muichiro, hollow eyes almost pleading. “I will clear a path. All you need to do is kill the Upper Moon.”

Muichiro’s eyes widened. His shaking stilled.

…That’s right; he just had to kill the Upper One and everything would fall into place.

This was… the only way.

“…Do what you have to do.”

Sorry, Yui. But I gave you a chance.

The shadow seemed to grin. It turned, and Yuichiro stepped back, his grip on his sword tightening. The red mist began to gather around its body; it pulled the mist from all over the arena, as its form started to shift, growing bigger and longer. Hands turned into claws, horns sprouted from its head, and its face opened up in a mouthful of teeth.

“Get away, now!” Kokushibo roared.

Yuichiro and Sanemi leapt back as the mist exploded outward and a massive dragon stomped on the ground, throwing up a cloud of red haze in its wake. Its six eyes focused on Yuichiro as it roared and brought a claw down between him and Sanemi. They jumped out of the way, and it followed after the Mist Hashira, claws swiping to force him back. He dodged each strike, quickly realizing that it was no longer trying not to harm him.

“Tokito!” Sanemi tried to run to Yuichiro’s aid, only for the guardian’s sweeping tail to whip towards him. He dropped and slid beneath it, but not quite low enough; the misty tail grazed his shoulder, searing a harsh burn across his skin.

“Aniki!” Genya called out. The guardian turned its head, watching him run towards his older brother. It grinned and opened its mouth, crimson light pulsing in its throat before it unleashed a blast of red mist right between them. The force of the blast gouged a scar in the ground; it spun around, continuing to breathe out the red mist and fill the air with its burning haze.

As the guardian wreaked havoc, Muichiro saw his chance. He dove into the mist, running towards the Upper Moon One. A crescent cut through the haze, barely missing him as he dropped low. Their eyes met.

Muichiro could see that the Upper Moon was starting to falter. Genya’s Blood Demon Art had weakened him, and the red mist was eating away at his flesh. The pain was slowing his movements, so slightly that no one else would have noticed. But he did.

Muichiro raised his sword; it changed shape, growing longer, multiple smaller blades branching from the main one. The red mist spread by the guardian moved towards him, gathering and infusing into his blade. Kokushibo altered his own sword’s form to match, but whatever he did, it wouldn’t matter. Muichiro would end this, right here and now.

“Muichiro!” his brother’s voice called. The guardian roared, lifting a severed claw. He saw Yuichiro for just a moment, face pale with fear and desperation. “Muichiro, please-!” The guardian’s tail slammed down in front of him, his voice drowned in the howling mist.

Muichiro felt something snap; he couldn’t… he couldn’t stand seeing his twin’s face look like that. So unsure, so afraid, because of him. The shadow snarled and moved, curling around him, leaving the mist to keep the humans away.

“Kill the Upper Moon,” it still spoke in Yuichiro’s voice. “Put an end to this, once and for all.”

The red haze closed in, blinding him to all but the Upper Moon One. Their movements were mirrors of each other. The guardian opened its jaws, light building in its throat. Both demons yelled out at the same time.

“Moon Breathing, Fourteenth Form: Catastrophe, Tenman Crescent Moon!”

“Devour!” Muichiro screamed, and the guardian breathed a stream of red mist alongside the storm of crimson crescents released from his blade. They flew to meet the glowing mirror unleashed by Kokushibo; the two techniques collided and clashed for a single second. And then the mist pushed through, swallowing the Upper Moon entirely.

For a moment, all was still. Muichiro breathed heavily as he stared through the mist. Did he…?

“Move!” the shadow cried.

Its warning came too late. Muichiro looked up just in time to see a crescent slash crash down from above and rip through his body. The guardian was scattered instantly from the force of the blow. Two more came down in succession, shredding his body further. He suddenly couldn’t see.

How? His mind raced to understand what had happened. But he quickly figured it out; Kokushibo had used another technique right after the fourteenth form, delayed ever so slightly so it wouldn’t be impeded by Muichiro’s mist. He hadn’t seen it coming from the chaos of their techniques colliding.

But it didn’t matter. He would heal. Would Kokushibo be able to do the same?

The mist parted; through his gradually returning vision, he saw the Upper One still standing. Or rather, kneeling, his body reduced to bone and muscle that was regenerating slowly. How had he survived? Did that second technique dispel the mist just enough to save him?

But seeing him draw breath made Muichiro see red all over again. The mist returned to him, carrying Kokushibo’s blood. He felt a rush of power, his mutilated body quickly regenerating. The last shreds of his twin’s haori fluttered to the ground, but Muichiro didn’t even look at them, eyes focused only on the Upper One.

So what if he was still alive? He could barely move. And Muichiro was only growing stronger, his opponent’s strength becoming his own. This next attack would be the last. The guardian reformed around him, grinning with anticipation as his mist sword reappeared in his hand.

“Muichiro.”

Muichiro froze. He turned his head, watching as Yuichiro approached. His uniform’s sleeve was torn, revealing an ugly burn across his right arm. Muichiro stared; did he do that? When…

…it didn’t matter. “Don’t interfere.”

Yuichiro glared. “...Answer me, Mui. What do you think will happen to you once you kill him?”

What? Why was he asking that? Muichiro knew what would happen. He’d take Kokushibo’s blood, his power. After that, he’d kill any demons still alive in this castle. And then Yuichiro would kill him, the last of the Upper Moons. That was the way it had to be.

“I’ll tell you,” Yuichiro continued, “The Upper Moon One has the largest amount of Muzan’s blood inside him. If you eat him, you’ll lose control. What happened on Mount Takao will happen again.”

“Ignore him,” the shadow growled. “Do not forget that he is protecting your enemy!”

Two versions of Yuichiro’s voice clashed in his mind; Muichiro closed his eyes tight. The mere mention of that horrible night sent a chill through him. No, he wouldn’t lose control… would he? But he’d already hurt his brother and friends; he’d already crossed that line…

Yuichiro raised his sword. “I won’t let you do that to yourself.”

Muichiro’s body shook. His head was pounding from the red haze trying to take over. “Why… why are you defending him?!” His eyes opened, and before he could stop himself, he closed the distance between them, taking Yuichiro’s collar in his hand and holding a claw to his face. “Why are you protecting him?! He’s an Upper Moon! A monster! He deserves to die!”

Their faces were inches apart; Yuichiro paled, teal eyes going wide. “Muichiro… your…”

“What? What are you…”

And then he realized it. He was seeing clearly with all six eyes, the feeling of holding back his regeneration no longer present. The red mist no longer hid the symbol of his shame. From faraway, he heard Genya gasp, and Sanemi growl, “Muzan… that bastard…!”

Yuichiro stared, at a loss for words. He reached up and took Muichiro’s claw in his hand, holding it gently. “...Is this why you think you have to die, Muichiro?”

Muichiro couldn’t speak. Cold shock chased the haze away, and he was suddenly far too aware of himself. His pounding heart, the rushing of his blood, his increasing breaths; they were all too loud in his ears. He released his grip and took a step back, but Yuichiro held on tight. “Wait! Please, Mui, don’t run away again!”

Muichiro’s eyes widened. Don’t run away… He thought back to the night when everything went wrong. On that night, he’d gotten scared and ran away, into the waiting arms of Upper Moon One. He’d been scared, because he thought he might hurt his brother, his friends…

But wasn’t he doing that now? He looked at the burns on Yuichiro and Sanemi left by his mist, and then to Genya’s missing hand. He looked at Kokushibo, the second most powerful demon to ever exist, barely recovered enough to stand on his feet. Finally, his gaze turned back to the guardian and its monstrous form, looming above, its six eyes watching him.

His shadow, the monster he didn’t want to be. He’d given it power, let the rage and hatred - not for Upper One, but for himself - take over. He had become that monster.

Tears blurred his vision; he felt Yuichiro pull him close. “I’m sorry. I wish I could have stopped this. You suffered so much, and I wasn’t there for you. I broke our promise.”

“N-No, you didn’t…!” Muichiro choked on a sob. He wanted to tell Yuichiro that he was what kept him going during his captivity. That the hope of seeing him again allowed him to persevere. But he could barely get any words out. None of this was Yuichiro’s fault; it was all his. All his suffering was because of who and what he was: a demon, cursed by the gods.

“Listen, Muichiro.” Yuichiro held him close. “That number in your eyes, it doesn’t mean anything. You’re still my twin brother, and I love you. We’re going to get through this, okay?”

“How…?”

“The same way we always do: together,” Yuichiro pulled away to give him a teary-eyed smile. “I was trying to tell you this earlier, but… we have the cure!”

Muichiro’s heart skipped a beat. “What?”

“Tamayo’s cure is complete! Nezuko already took it; she's turning back into a human as we speak. And she gave me a dose as well,” Yuichiro explained. “Don’t you see? We can make you human again!”

Muichiro stared at him. He hadn’t even thought about the cure in so long; he believed he’d be dead before he would ever see it. His heart pounded, feeling hope and fear in equal measure. “But… what if it doesn’t work?”

“It will!” Yuichiro sounded so certain; it made Muichiro want to believe as well. He looked away, reaching into his pocket.

Kill him.

Muichiro let out a gasp. His vision flashed red, pulsing in time with a searing pain running through his skull and down his entire body. His eyes were burning…!

Kill him!

This voice… this was different from the shadow’s voice. He hadn’t heard it since that night on Mount Takao…

Did you think you could escape me so easily?

The pain surged, every muscle in his body locking up. He couldn’t move.

You are Upper Moon Five.

You are mine.

Against his will, Muichiro’s claws extended.

—

Yuichiro reached into his pocket, feeling the box that held the cure. But before he could take it out-

“Look out!” Sanemi yelled.

A flash of purple moved past Yuichiro, and he looked up in time to see Kokushibo’s sword clash with Muichiro’s claws. Yuichiro’s gaze turned to his twin; he had a terrified look on his face, the kanji in his eyes glowing white-hot. Something was very wrong.

“It hurts…! I…!” The white light in his eyes glowed brighter, and Muichiro screamed, stumbling back. The guardian shrieked and convulsed before collapsing in on itself. But the mist soon rose again, surging forward. Kokushibo picked up Yuichiro and leapt away just as the mist crashed down where they stood.

“What’s going on?!” Yuichiro shouted, unable to look away from his brother, who seemed to be struggling against his own body. “What’s happening to him?!”

Kokushibo narrowed his eyes. “I suspect… that Muzan is attempting to take control. Muichiro broke free of his curse… so he was unable to do so before. But when he marked him as an Upper Moon… he must have placed a different curse on him…”

Muichiro screamed again, a sound of raw agony, and the mist swelled before lashing out in all directions. There was no aim or intent in his strikes, only the wild thrashing of an animal in pain.

“So what the hell are we going to do?!” Genya shouted as he ducked under a wave of mist. Another one came right after, nearly taking off his head if not for Kokushibo pulling him out of the way. “Shit, that was close!”

“Stay vigilant. Do not let yourself be distracted,” Kokushibo told him.

“Keep your hands off him, you six-eyed freak!” Sanemi growled before dodging another misty tendril and turning to Yuichiro. “Hey, Tokito! You got some kind of plan here?!”

“I…” Yuichiro couldn’t answer. Muichiro’s cries were daggers in his heart. He was reminded of Mount Takao, but a hug wasn’t going to stop this.

Sanemi’s glare softened, and he spoke more gently. “Tokito, look at him. He’s suffering. Remember what you told me that night? You have to-”

“No!” Yuichiro snapped out of his indecision and shook his head. “No, I can still help him!”

“Damn it, kid, stop letting your emotions-!”

“I’m not! He’s being controlled; he doesn’t want this! But we have the cure! If I can just get close enough to give it to him, I can stop this!”

“And how do you plan on doing that?!” Sanemi asked.

Yuichiro didn’t have an answer to that. But before he could think, he and Sanemi had to dodge out of the way of another attack. Sanemi was right; what could they do if they couldn’t even get close?

Kokushibo spoke next, but not to Yuichiro. “You. Demon eater. Your Blood Demon Art… drained my blood to sap my strength, did it not?”

“Huh?” Genya realized the Upper Moon was talking to him, and his face paled. “Um, yeah, that’s right. Hey, uh, sorry I shot you earlier, I didn’t-”

“That is unimportant. Can you use it again?”

“Y-Yeah, sure,” Genya nodded rapidly. He held up his gun in his remaining hand, infused with demonic flesh. “I just need a clear shot.”

Kokushibo nodded. “Good. If we can weaken him… Muichiro may be able to regain control. Use nonlethal attacks. Force him to spend energy regenerating.”

Yuichiro felt his heart clench. If he hadn’t wanted to hurt Muichiro before, he certainly didn’t want to now. But if this was the only way to save him…

He gripped his sword tight. “…Let’s do this.”

“Tch, taking orders from an Upper Moon… but fine, I’ll do it for the kid’s sake,” Sanemi relented.

Kokushibo dodged another tendril and raised his sword. “Moon Breathing, Eighth Form: Moon Dragon Ringtail!”

A massive crescent slash tore through the crimson cloud. Muichiro was revealed, and Genya raised his gun and fired. But Muichiro’s claws just sliced through the bullet, and he wrapped himself in mist before lunging at Yuichiro.

Sanemi’s sword intercepted the attack. He pushed back, hissing as the red mist burned at his exposed skin. “Fuck, this shit really stings…!”

“I’m sorry!” Muichiro cried, frantic. “I don’t want to, I-!” He screamed and raised his other claw, and Sanemi’s foot struck out to kick him away.

Kokushibo leapt in, using his altered katana to force Muichiro further back. Or that was his plan, but Muichiro didn’t dodge. The katana lodged into his right side, Kokushibo only just stopping his swing before it could cut him in half. Sanguine mist poured from the wound, forming a beast that lunged for the Upper Moon’s head.

“Mist Breathing, Third Form: Scattering Mist Splash!”

Yuichiro’s strike dispelled the beast, and Kokushibo leapt away, blade still embedded in Muichiro’s side. But the mist simply melted it, the wound healing quickly.

“Wind Breathing, Second Form: Claws-Purifying Wind!”

Muichiro leapt back as Sanemi came in with a rapid series of downward slashes. They cut shallowly, and he moved back in, claws raised to strike from above.

A rattling chain sound accompanied a massive spiked ball sailing over his head. Muichiro stopped and looked, only for the chain to go taut and the ball to come flying back. He stepped back to avoid it, and the chain wrapped around his body, the momentum of the flail pulling and throwing him against one of the few standing pillars.

Yuichiro let out a breath; that weapon, it could belong to only one person! “Himejima?”

Heavy footsteps announced the arrival of the Stone Hashira. “I am glad Ginko led me here. Poor Muichiro… I believe I understand the situation. I will aid you in your efforts to free him from Muzan’s control.”

“Well, this is getting more interesting by the second,” Sanemi grinned. Yuichiro couldn’t say he agreed, but any help was more than welcome.

Muichiro struggled against the chains binding him, but Gyomei’s nichirin flail had wrapped tight around the pillar, keeping him trapped. Yuichiro knew he could get out easily using his Haze blood art, but for some reason, he didn’t. Why was that?

A gunshot rang out, and a bullet struck Muichiro in his left shoulder. He cried out in pain, right before the Devouring Mist burst out of the pillar, destroying it instantly. The mist rolled towards the five of them in a massive wave.

“Stone Breathing, First Form: Serpentine Bipolar!”

“Wind Breathing, Seventh Form: Gale, Sudden Gusts!”

Gyomei and Sanemi attacked together, and their combined techniques blew a hole in the oncoming cloud. Kokushibo moved next.

“Moon Breathing, Sixteenth Form: Moonbow, Half Moon.”

Kokushibo swung his blade up, and six giant crescent slashes rose into the air before crashing down from above. The sheer force of their impacts scattered the rest of the mist and left craters in their wake.

“Woah…” Genya breathed. “Glad he’s on our side now.”

Yuichiro nodded, but he kept his eyes on the mist shrouding his twin. The Devouring Mist reformed, only to suddenly collapse. Muichiro stumbled, a tree sprouting from his shoulder. But something was different. The tree seemed to be wilting, its bark flaking even as it continued to grow. And then the trunk swelled and split open, red mist leaking out with a hiss as the whole tree crumbled.

Suddenly Yuichiro remembered; Muichiro’s blood was harmful to demons, and the Devouring Mist melted right through other Blood Demon Arts. “Damn it! It’s not going to work!”

“No, it will. Even if the trees are destroyed, they are still draining his blood. Use it again,” Kokushibo instructed Genya before diving back into the fight. Genya nodded and raised his gun with a conflicted expression, one Yuichiro shared.

But Muichiro - or Muzan controlling him - seemed to realize that Genya was the greatest threat now. The red mist burst in all directions, driving back Sanemi and Kokushibo, and he dodged around Gyomei’s ax and flail to lunge at the demon eater.

Yuichiro grit his teeth and put himself between them. “I’ll handle this! Focus on finding an opening!” He raised his blade and blocked the incoming strike. Though Muichiro’s claws didn’t touch him, the thick red mist seared at his skin.

But even worse was that the mist moved around him, heading for Genya while he was occupied with fending off his brother’s puppeted body. He noticed the mist spreading throughout the battlefield, clouding the air despite his companions’ efforts to drive it back. If this kept up, it would swallow them all.

“I… I…” Muichiro struggled even to speak now through Muzan’s control. “Eye…s…”

Eyes?

Of course, the kanji! Muzan had only taken control after Muichiro regenerated his marked eyes. He must need them intact for his curse to take effect!

But that meant…

“Damn it… Sorry, Mui. I don’t want to hurt you, either. But I’m going to save you!” Yuichiro lifted his foot and kicked Muichiro away, then swung his blade up, nichirin steel slicing across his face.

Muichiro cried out, but instantly the Devouring Mist started to falter, pulling away from their companions. It fell low as Muichiro fought to raise his claws to his face. Mist bled from his slashed eye that refused to heal, even as the other eye’s kanji glowed furiously.

It was working! “Genya!”

“Right!” Genya fired a bullet at Muichiro’s chest, knocking him back. The mist rose as Muzan gained the upper hand once more.

“Stone Breathing, Fourth Form: Volcanic Rock, Rapid Conquest!”

“Wind Breathing, Sixth Form: Black Wind Mountain Mist!”

Gyomei and Sanemi’s attacks ripped through both his arms, and another tree sprouted from the bullet wound. The new tree grew faster than the first, lasting longer as it curled around him before inevitably starting to wither. The mist dropped low and began to fade.

Yuichiro was starting to think they’d succeeded when Muichiro suddenly let out an agonizing scream. It was like nothing he’d heard from him before; the kanji in his eye flickered dangerously.

Kokushibo’s eyes widened. “No! Muzan’s going to kill him!”

Yuichiro's heart dropped. "What?!"

Muichiro’s screams reached a crescendo. But then suddenly the sound shifted, turning from pain to anger. His arms regenerated, and then Muichiro dug his claws into his face and ripped out his marked eyes. A horrified silence fell that was broken only by Muichiro’s labored breathing. Blood ran down his face and hands as he crushed the cursed eyes in his grip.

“Oh… Oh god…” Genya looked like he was going to be sick. Sanemi looked similarly horrified. Gyomei couldn’t see, but he knew what had happened; his expression was tense. Kokushibo simply watched stoicly.

Muichiro fell to his knees, his gasps soon turning to broken sobs. His other eyes closed, but he didn’t regenerate his original pair. Yuichiro sucked in a breath and rushed over, kneeling and taking his hands in his own. He didn’t care about the blood; he needed his brother to know he was there.

“I can’t take this anymore…!” Muichiro cried. “I want to die!”

Yuichiro’s heart shattered all over again. “Don’t say that, Mui. I’m here for you; we’re all here for you.”

Muichiro shook his head. “It’s not something you can fix; it’s everything…! My body and mind, they aren’t my own! I’m hurting people without even trying! And the anger, the hate, it keeps getting stronger… I’m losing myself…”

Yuichiro couldn’t think of anything to say. He wanted to blame himself for failing to protect Muichiro, but the truth was that this had been building for a long time. It was the culmination of three years of trying to be human when the whole world wanted to remind him he wasn’t. In the absence of any comforting words, he pulled his twin into a hug, letting him cry on his shoulder.

“That thing, the shadow… it's a part of me,” Muichiro went on. “It’s the part of me that’ll do anything to survive. So I wanted… I wanted you to kill me. I didn’t want it to win. I didn’t want to keep living as a monster…!”

“I told you, Mui, you’re not a monster. You’re a demon, but that’s not the same. And you don’t have to keep living as a demon, either. We have the cure. We’ll make you human again, and these awful things will stop.” Yuichiro wasn’t sure if that was entirely true. Could Tamayo’s cure undo the trauma, the anger, the malevolent voice inside his head? But at the very least, becoming human would mean Muzan would no longer have power over him. It would take away his claws, his fangs, and the red mist that harmed as much as it empowered him.

Muichiro didn’t respond; he let out a whimper and buried his face deeper in Yuichiro’s hair and shoulder. The older twin sighed. “Come on, Mui, stand up.” Muichiro silently complied, allowing Yuichiro to help him up.

The older twin looked back at his companions; Gyomei and Kokushibo had stayed back to give them space, while Sanemi and Genya were quietly conversing. He’d hoped they might have some words to help Muichiro, but quickly dismissed the idea; none of them were the comforting type, anyway. It was up to him.

Yuichiro turned back to his brother. “Mui, do you really want to die?”

He didn’t answer. “There’s no coming back when you die. But as long as you’re alive, things can get better. You have so many people who love you, Mui! I love you! I don’t want you to die; I want to grow old with you and all our friends! Don’t you want that, too?”

They’d already lost so many people tonight, and who knew how many more would follow before Muzan was dead? But if Yuichiro could only save one person, let it be his little brother.

Muichiro was quiet for a long time before answering. He sniffled and spoke in a soft voice. “I… want to...”

The twang of a biwa echoed. Muichiro froze. And then he pushed Yuichiro away.

Yuichiro reached out towards his twin. “Muichi-!”

Something slashed through his left arm. Kokushibo leapt forward, grabbing hold of Yuichiro and pulling him away, but he barely noticed. The pain didn’t even register at first; the shock numbed him to all else. But as he looked down at the limb, suddenly just gone from the elbow down, bleeding profusely, the shock wore off. He bit his tongue to hold back a cry of pain.

But that pain was nothing against what he saw next. Muichiro fell to his knees, a stunned look on his face and hollowed eyes wide.

His head tumbled to the ground, cut cleanly at the neck.

A man - no, a monster - stood behind him. Long white hair, dark red limbs covered in mouths full of sharp teeth; even having never seen him before, he was unmistakable.

Muzan Kibutsuji, the Demon King.

“Pathetic.” A blood-stained nichirin sword gleamed in his hand. “You were a disappointment to the very end.”

Yuichiro couldn’t breathe. He couldn’t think. All he could do was scream.

“Muichiro!”

Chapter Text

…

…

…Why?

He couldn’t see. He couldn’t move. He couldn’t feel his body at all.

But he could hear.

Yuichiro was screaming, crying out his name. He sounded like he was in pain. The smell of blood reached his nose; Yuichiro was hurt.

Other voices were yelling, but they were all distant. Only Yuichiro’s screams reached his ears. Why couldn’t he move?

The answer came to him then, an instinctive understanding.

Beheaded.

He’d had his head cut off before, when he’d been careless against other demons. But he knew this was different. He knew, this time, he wasn’t going to regenerate.

Was he dying? After everything he went through, was he going to die without killing a single Upper Moon? Without protecting anyone?

Why?

“Mui, do you really want to die?”

Yuichiro’s voice echoed in his head. Did he want to die?

No, it was just… the only way he could cope with the pain, the shame of what was done to him. He’d been branded a traitor, forever marked as Muzan’s possession. He couldn't see any hope for himself. He couldn’t see a way out of the darkness.

But Yuichiro had given him a light.

Yuichiro had told him they’d finished the cure. He’d told him that he could be human again, that things could get better again. But here he was, dying a demon’s death, his light extinguished. He would go to hell, as all demons did. What was the point of holding out this long? Why did he allow himself to hope?

Why?!

Why did the gods hate him? What had he done wrong? He didn’t eat humans, so why couldn’t he walk in the sun? He wanted to protect innocents, so why did his mist hurt them? He suffered so much for a life as a human with his brother, so why was he dying now, his precious twin right there?!

Why?!

…

There was no answer. There never was.

It was… so unfair.

He felt cold. Was this what death felt like?

Yui, where are you? I’m scared… I don’t want to die…

He didn’t want to die. That was the truth. He didn’t want to die. But there was nothing he could do. He was already dead.

His eyelids felt heavy. The fog in his head was closing in, pulling him under, trying to bring him peace in his last moments. He let his eyes close; it made no difference if they were open or not.

But he still felt tears run down his face.

…

You will not die here.

His eyes opened. The darkness was gone; a sea of red mist stretched on endlessly. Standing before him was the shadow in its true form. Its six turquoise eyes stared as it knelt before him. It reached out, a clawed hand resting on his head.

You will not die here. You can survive this.

How? Once a demon had its head cut off by a nichirin blade, that was it. He couldn’t survive.

You can. You are a demon with infinite potential. With a strong will, you can regenerate your head. You can overcome even death.

Regenerate his head? But that was impossible; what willpower could be strong enough to triumph over death?

The shadow was silent, its expression unreadable. It moved its hand and placed its claws on either side of his head, gently cradling him in its grasp.

Accept me.

His eyes widened. What…?

Accept me. Embrace what you have rejected. I am your will to survive. Accept me, and you will live. You can protect what is most important to you.

What was most important to him? But the answer came immediately, piercing through the fog.

Yuichiro. His big brother. His twin. His other half.

Yuichiro was always there for him, and he wanted to be there for him, too. He wanted to protect him from this horrible, unfair world. The gods had condemned him, condemned them. All they had was each other; he couldn’t lose him!

Whatever cut his head had hurt Yuichiro, too. Yuichiro was in danger! He had to protect him; he couldn’t die here!

The blood mist churned and roared, crying out his defiance of his cursed fate. He would not succumb. His rage was a fire that would consume the world.

The shadow closed its eyes. It lowered its head and touched its forehead to his.

Save him. Save yourself.

Muichiro felt the fire inside him, rising, engulfing his heart and soul. It didn’t matter what he had to do. He would destroy everything to protect his twin.

All he needed was Yuichiro.

Everything else could burn.

The mist swallowed them both.

—

“Muichiro!”

Yuichiro screamed, reaching out towards his twin. He didn’t care that he was bleeding out from his severed arm. He didn’t care that the Demon King was right in front of him. All he cared about was Muichiro, his head lying cut and motionless on the ground.

Kokushibo held him back from throwing himself at his twin. Yuichiro struggled against him, but he couldn’t break free of his hold. “Let go! Let go of me!”

“Don’t be foolish…! You’ll be killed as well…!” the Upper Moon snarled.

“I don’t care! I have to go to him! Muichiro!”

Muzan’s eyes narrowed. He turned to Muichiro’s body, and lifted a clawed foot to knock it to the ground. His foot dug into the young demon’s back. “All that power, and you couldn’t kill a single demon slayer. You disappoint me, Upper Moon Five.”

Yuichiro sucked in a breath, his anger surging. How dare he talk about his brother like that?! “You… you bastard!”

Muzan lifted his head, looking at Yuichiro with a dismissive gaze, as if he were little more than an insect. “Oh? Am I wrong? All demons are created to serve me. A demon that can’t do that is worthless.”

Yuichiro growled, but then he felt Kokushibo’s grip on him loosen; the demon pushed Yuichiro behind him as he stood up. The sheer fury in his six eyes was terrifying. “Muzan…!”

The Demon King glared. “I don’t recall giving you permission to speak my name, Upper Moon One.”

“I am your Upper Moon no longer… That child… Muichiro… do not speak ill of him! He showed me that a part of me was still human; he is worth more than my loyalty to you ever was!”

Yuichiro gasped. To see Kokushibo stand up to his master like this, for Muichiro's sake... he really had changed.

“Is that so…?” Muzan looked utterly unaffected by Kokushibo’s anger. He tossed the nichirin blade aside and raised a hand, and the former Upper One gasped as his body suddenly seized up. He fell to his knee, choking, cracks forming along his skin. “In that case, you can die here with him. I have no use for traitors, and once I’ve wiped out the Demon Slayers and conquered the sun, there won’t be any need for other demons at all.”

Kokushibo couldn’t speak as the cracks continued to spread, his body falling apart at a cellular level. He was powerless to fight back. Yuichiro wanted to help him, but he didn’t know how; his pain and despair left him frozen.

Muzan’s fingers slowly closed into a tight fist. “Farewell, Upper Moon… hm?”

His eyes shifted, and a flash of white missed the Demon King’s head by mere inches as he jumped away. The cracks stopped spreading, and Kokushibo fell to all fours, gasping for air.

Muzan landed several feet away and glared. “Well, isn’t this a surprise? You would betray me too, Akaza?”

“Don’t call me that,” the Upper Moon Three glared back. “My name is Hakuji. And I’m through with following your orders.”

“…Very well; I have no more need for any of you!” Muzan raised his hand again.

“Water Breathing, Third Form: Flowing Dance!”

A sword sliced through the Demon King’s wrist; it healed before the hand could even separate, but it was enough to distract him. Amidst a stream of water, Giyuu came to a halt, his usually impassive face alight with anger.

Muzan was starting to look irritated now. “Annoying pests!” His arm transformed into a thorny tentacle that lashed out towards the Water Hashira. But Gyomei’s flail intercepted it, his ax swinging next to chop through the limb.