Chapter Text
It's as if his words have flipped a switch. As soon as she finishes speaking all room for banter vanishes, and Itachi finds himself fending off a sudden deluge of sword strikes. He has to activate his Sharingan at once to avoid drowning. He hadn’t even seen her bend down to pick up her blade; the onslaught of speed is incredible.
As he begins trading furious blows with his opponent, a sense of terrible strangeness begins to overcome him. This isn’t Sagi, he finds himself thinking. In itself it is an incomprehensible thought; who else could she be besides Sagi? But still, something is wrong. He knows his sister is skilled, and he has long suspected that she has been holding herself back, but “holding back” can't account for this performance. This gap in skill level is impossible to fake. Like he’s fighting someone five—no, ten—more than ten years older…
Until now he’s only ever faced his sister in relatively contained matches, focusing mostly on taijutsu and bukijutsu. But all at once she begins integrating the whole of the ninja arts. Hidden weapons, wired shuriken, kicking sand and scorching ninjutsu—
And then, as he dodges past the blazing fireball, frighteningly vivid genjutsu. In a moment the whole world inverts: the sky is the ground, the trees stretch out sideways, his sword is on his foot, and he’s making hand seals on his forehead. When he tries to lift his leg, his arm swings instead, and when he exhales, the breath comes out his back. Then he looks at Sagi, long-haired and empty-eyed, and feels at once as if the sight might drive him mad.
He shatters the genjutsu with a pulse of chakra. With perception corrected and limbs reoriented, he shakes off the surge of emotion and dives on his opponent instead. Sagi brings up her sword to parry him, but his strike slides down the length of her blade and catches at the edge of the tsuba; her hand jerks to the side. His sister tsks with annoyance.
That’s not the first time that’s happened today, Itachi thinks. Despite her sudden and inexplicable level of combat mastery, she seems to be repeatedly mispositioning her weapons. It's almost as if she’s fighting with gear that’s not hers and is trying to adjust to the difference on the fly. Itachi has no idea why this would be the case, but the Sharingan’s acuity shows him that she isn’t faking it, so he presses the attack.
The tempo of the fight, which had started in Sagi’s favor, settles into a pace he can comprehend. Now that he’s found the rhythm, Itachi doesn’t intend to stay on the back foot forever. He swiftly launches his counterattack.
Sagi begins to fold. He herds her towards the edge of the cliff, calmly slicing through wire and flinging shuriken of his own to deflect hers. He rams his knee into her stomach when she’s mid-breath for another Great Fireball, and a second later her blade goes flying from her hand. He has her on the ropes and he knows it; the fight will be over soon.
Except—
Except the whole time, as he drives her deeper and deeper into the jaws of defeat, he’s cracking genjutsu after genjutsu after genjutsu. Her form flickers constantly, but the most distracting thing of all is the hair. Every time he turns his gaze back to her it’s long again. Sometimes braided, sometimes ponytailed, but most often hanging loose… it’s constantly flowing through his peripheral vision, alerting him to the fact she’s laid another illusion over him. He doesn’t know what she gains by peppering him with such meaningless images, and though he can guess she’s doing it for some sort of psychological effect, the fact that he doesn't know what that might be makes him wary. But still, it's not as if he can let her cast genjutsu on him unanswered, so he continues breaking each one as it comes.
Finally they come to the precipice. Sagi’s heel is hanging over the edge of the cliff; Itachi, blade raised, lets out a short breath before lunging. But he doesn’t let his guard down. He keeps ready to respond to whatever final trump card she must have hidden up her sleeve.
He doesn’t expect her to throw down her kunai and drop to her knees.
Itachi only manages to avoid impaling her by forcing chakra into his feet and sticking them hard to the ground. The sudden brake causes horrific muscle strain all the way up the right side of his body, and he feels a particularly terrible twinge in his calf. But even though his heart shoots up into his throat, the tip of his blade stops just short of running her through. Breathless at the close shave, he lets out a short gasp.
A beat of silence passes. And then, slowly, Sagi raises her head and peeks at him through the gap between her fingers. Her irises are a bright Sharingan red.
“Itachi?” she asks softly. Itachi pulses his chakra again; her hair falls over her shoulders.
That's the first time she’s called him by name in years.
“What are you doing,” he exhales more than asks. Man alive, he doesn't know how he deals with her. “I could have killed you.”
Sagi drops her hands and stares him dead in the face. Contrary to his look of tired exasperation, her gaze is direct and unflinching, and her voice is abruptly full of cold determination.
“Yes,” she agrees. “Yes, Itachi, you could have.”
He catches her as she slumps forward. She lets out a soft noise, just the quietest of choking breaths, and reflexively grabs onto his arm; he lets her, and holds her steady as he lowers them both to the floor. He supports her back while she gasps into his chest. Then he holds her like that, recording every second of these last moments with red eyes.
He waits for her to pass. There’s still more to do—more slaughter to carry out, more words to say, more seeds to plant when Sasuke comes—but for now, just for now, he’ll stay with her. It’s the least he can do for his sister after murdering her and the clan. It’s the last thing he can do for her—her, his twin, his companion since birth.
She shifts. Itachi helps her, turning her shoulders and adjusting her body until the back of her head comes to rest in the crook of his arm. She lets out a low groan of pain. Blood is dribbling over her chin, but despite how rapidly the color is draining from her face, her irises still turn red. Itachi watches as the tomoe spin into place, full of pity, because he knows that the Sharingan can do nothing for her now.
But then she speaks. “Next time will be different,” she whispers. “No more of this. Next time, I won't just wait to be killed by you again…”
Her gaze drifts upwards, unfocused, and the pattern in her eyes shifts. Itachi finds himself suddenly faced with a Mangekyou Sharingan. Hypnotized, he stares into the pinwheel pattern. Spinning as if in the wind, turning backwards, back and back again…
Lost in her gaze, the moment is almost dreamlike. He’ll remember this, too. Yes, he will remember. He…
He wakes up.
She’s already thrown herself over the edge by the time he thinks to lift his hand. Horrified by the tardiness of his own reaction, he reaches out in vain for her plummeting body, but she’s already gone; there’s nothing he can do. He can only watch the descent. She falls and falls and then smashes into the water; from here, the sight of it is no more than a tiny pinprick of a splash. He can't even hear it at this height.
Several moments pass in silence, broken only by the distant roar of the water. The river rushes onward, indifferent, as his eyes search its rapids in vain for her body. He kneels at the cliffside, dumbfounded, for several minutes.
His mother opens the door when he returns home. She drops the glass in her hand when she catches sight of her son’s eyes.
Though the adults are scrambling and the police have formed search parties, the rest of his tenth birthday goes by as if in a dream. He knows they won't find her, and they know it, too; but he keeps on, serene as ever, as if everything will fade away just as soon as he opens his eyes again. Now, he thinks, it's only a matter of passing the rest of the day. It's only a matter of waking up again tomorrow.
But even when he wakes, he thinks he will remember. Yes… he knows he will.
Uchiha Sagi is dead, and Itachi suspects that he is the one who killed her.