1 - 20 of 488 Works in Post-Undertale Neutral Route
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Summary
Their King is dead. The six Souls are Gone. Their future lays in ruin.
Frisk has slipped through the barrier and left the monsters with shattered hopes and a toppled monarchy. With no witnesses, it was pure, selfish regicide. They were loved by all, and thus, their betrayal cut all the deeper. For the third and final time, humans had stolen everything from them.
Anger has a way of changing people. It remains in the Soul even as memories fade.
Frisk may be gone, but the RESETS continue, multiplying the resentment within them and morphing the residents of the Underground into tightly wound reflections of their former selves. No longer in a position to do nothing, Sans is Determined to find a way past the barrier for the sake of his brother, and for the sake of justice.
He’ll give anything to achieve that goal. His Soul included.
He’d found an alternate method that should work, buried deep inside a gilded dusty tome in the royal library. Instead of using LoVe to pass through the barrier, Sans was going to use love. He was going to have to gain a consenting human, and convince her to bind her Soul to his. Permanently.
Series
- Part 4 of The Butterfly Effect 💚💛🧡💜💙🩵❤️
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A Hopeless, but Fun Game by WhatamIDoing_GoodQuestion
Fandoms: Deltarune (Video Game), Undertale (Video Game)
24 Aug 2025
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Cursed with knowledge from a strange man, Seam tries to have some fun with their friends even after having relived the same days over and over again, knowing about the human who keeps falling down. They try to not think about it too much, but it doesn't always work out.
Luckily, they have some great friends, especially a certain jester companion.
Series
- Part 1 of Darkners? How About Monsters!
- Language:
- English
- Words:
- 4,323
- Chapters:
- 1/1
- Kudos:
- 7
- Hits:
- 57
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Summary
Someone claimed that the principles of justice are chosen behind a veil of ignorance. But when it comes to the time to choose, can Sans make a just one?
He didn’t understand why he had done it. Standing in the freezing winds of Snowdin, with snowflakes swirling like silent witnesses to his hesitation, he came to the horrible realization that he never understood anything.
But now, under a blazing sun that cast no shadows, Sans would squint at the open sky and wonder if his choice had meant anything at all—or if it was simply another link in an unbroken chain of futility. The warmth on his bones did nothing to erase the cold from his memory. And he will, yet again, remember the distant day when he made the choice.
Snowflakes falling. Moments dissolving.
A sky too bright to understand.
Series
- Part 6 of Weight of This Sad Time We Must Obey
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We All Have Tales by ThatWiseOwl
Fandoms: Deltarune (Video Game), Undertale (Video Game)
19 Aug 2025
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Summary
Just their luck to break their fall on top of those pretty yellow flowers get a 'minor' concussion and be taken in by a tall goat monster and her barely tolerable skeleton roommate. It could be worse, if the mean purple lizard monster and the anxious deer ever decide to quit trying to kidnap them.
Deltarune/Undertale AU - What if Kris fell into the underground years after an abandoned neutral route, where a fishy empress is out for human blood for killing their best friend.
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We'd Miss the Snow Poffs, Anyway (Sans/Monster Reader) by ComicalFont
Fandoms: Undertale (Video Game)
15 Aug 2025
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The human had been kind to the monsters of the Underground, not hurting anyone on their way, but ultimately made the choice to defeat Asgore. No one could really blame them, but the six souls disappearing put a damper on any vacation plans on the surface. Everyone's impacted one way or another, including you, a bear monster living in Snowdin. After spending some time visiting family to see how everyone's doing, you're back home to catch up with Sans, your best bud and recently your new special someone, to see how he's bear-ing with the news. Maybe you can find something silly to do to get the news off your minds...
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Mettaton and Muffet become the king and queen of the Underground after Asgore's tragic death. Will they do a good job or is the power getting to their heads?
- Language:
- English
- Words:
- 6,745
- Chapters:
- 2/?
- Hits:
- 17
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Summary
This takes place in a post Underfell King Papyrus ending.
Struck by under population, King Papyrus makes it law that all monsters left alive by the murderous little human have to procreate. This leaves Fell!Sans and The King himself in a tight spot. There are no female skeletons left in the whole Underground and both skeletons are sure they are the last of their species. Fell!Sans proposes something. With the help of the first Royal Scientist's machine to travel to other universes, he will find mates for breeding purposes.
Tale!Sans is having his first sub heat as a female. This happens when there are only males left and the strongest one undergoes a gender swap. He knows this means Papyrus will have to be his mate.
That won't do. They are brothers, for the Angel's sake! So he does what he does best, HE RUNS.
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Follow Grillby as he ventures through the underground after a genocidal child emptied it.
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메타톤 즉위 엔딩 이후 혁명으로 축출해낸 메타톤에게 이것저것 하는 내용
- Language:
- 한국어
- Words:
- 817
- Chapters:
- 2/?
- Hits:
- 27
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Summary
Papyrus is crowned king. All Sans can do is watch as this ruins his brother.
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You Felt A Sense Of Justice Fill Your Soul by Just_aFreak
Fandoms: Undertale (Video Game), Undertale Yellow
15 Jul 2025
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Summary
After finishing a neutral run and speaking to Flowey, Frisk makes a decision that will determine the fate of the entire Underground.
They go back to the start to do everything again, and they'll do it right this time. Befriend everybody, hurt no one. Get their 'perfect ending.' whatever that means. Even if they have to do it alone.
Or will they...?
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Toriel grapples with the consequences of the Human's departure, and her own personal revelation.
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King Mettaton (and Royal Advisor Alphys) Ending by orphan_account
Fandoms: Undertale (Video Game)
29 Jun 2025
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Your post-playthrough phone call from an old friend. What if Alphys and Mettaton ruled the Underground together? Could it have been a happier ending?
Story is told entirely in embedded text images.
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In a timeline where no one may grow up under the sun, Dess sneaks Noelle out to Waterfall.
(Or: the kids have one good day.)
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The Monsters emergence to the surface had changed the life’s of many.
There were some who had a hard time believing it wasn’t just a hoax, the only changes in their lives being the occasional glimpse of a Monster shopping at the local grocery store.
For others, the change was more severe.
Mimics. Humans whose soul reacted to the wave of magic that circled the world over when Monsters broke the barrier.
Their souls altered their bodies over night, mimicking the appearance of random Monsters. Their very DNA changed, leaving millions scared and confused.
She was one of them. Gathered up and put into the Omega Mimic Adoption Agency until a pack decided to ‘adopt’ her.
She can’t except this new life.
She won’t.
She’s still a human- right?
Or: soft and angsty recovery/found family/romance A/B/O skeleton poly fic where everyone is actually in the poly. Everyone is healing, 50 something years post emergence Swapfell, Horrortale, Underfell, Underswap and Undertale mashup, plus one very traumatized skele MC learning to live and not just survive.
Tooth rotting fluff and bumbling idiots trying to pspspspsps and offer their hand for our bbg to sniff like a cat will ensue
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A boy fell into the Underground in order to avoid his pursuers. Under the flames of war, will he survive with tenacity alone?
- Language:
- English
- Words:
- 997
- Chapters:
- 1/?
- Hits:
- 6
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Summary
You wake up as someone who has nothing left to lose, stranded in an Underground that's slowly dwindling in life. Despite being capable of crossing the barrier, you don't dare to, when you have a personal endeavor and promise in mind.
It's a different story when you're transported into an ideal alternate timeline, where your oath is rendered void. Here, with your various counterparts, you don't appreciate reliving the life of a prisoner-- especially when it's enforced by a reflection of what your Sans could've been.
(OR: In a pacifist timeline, an alternate Sans possessing a human soul appears, risking the newly established peace between humans and monsters. If Classic Sans had hair, he's pretty sure he'd still end up bald.)
[A Various x Sans!Reader fic.]
Series
- Part 1 of parallax error
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Summary
Saur is a strange human, always has been, always will be. But her list of things that were on her 212X bingo card NEVER included finding a hidden civilization in a mountain that was not only still reeling from the last human to come down, but also ruled by a skeleton guy who doesn't really seem to embody the will of his people. Oh, and did I mention that her soul is deformed and never inside her body for some reason? Yep, this is about what you're getting into.
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System Error: Accidental Acquisition of Children by Frikisbits231
Fandoms: Undertale (Video Game)
14 Jun 2025
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Summary
Error slid down, glued to the tree, his back to the ground, into the lush green grass on the ground. Later, he'd take a look at his current situation and possibly eliminate the place without a problem. Meanwhile, Error was resting, leaning against this comfortable, curvy tree, closing his eyes to feel something, something of the place.
Feel... the familiar ambient magic?
Still no monsters, humans, or standard souls around. Well, no one could hurt him if he got some rest, right?
This time, he mentally prepared himself and repeated the safety tests he felt like a mantra so he could get some rest.
He fell asleep shortly after.
…
Sweetness with hints of security, calm, and the tranquility of dawning rest captured his senses. Something... familiar. Like... like chocolate melting on his tongue. He didn't know how he recognized that either. Still, he pulled the tongue out of his space, to capture it. He caught the sensations, almost becoming overwhelmed by them.
(O: The one where Error acquires an abandoned baby bone, which is, of course, his offspring too, yay...)
Series
- Part 3 of Glitches & Errors Fics
- Part 2 of Random Writing
- Part 1 of Caring for Babybones
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Hooray! King Mettaton Episode! by datm, grayishaffinity, MinkyMomouuu, visibrans, WPuppetMar
Fandoms: Undertale (Video Game)
06 Jun 2025
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PRIMARILY WRITTEN BY MINKYMOMOUUU AND GRAYISHAFFINITY!!!! DON'T TRUST THE ALPHABETICAL AO3 USERNAME LIST!!!
Alphys turned to Mettaton. “I, um.. need a.. a moment to think about this. I’ll see you later.”
“Wait, Alphys!” Mettaton tried to reach out to her, but she was already walking toward the basement elevator. “I'm here if you need to- ..talk," She probably wasn’t listening anymore.
And with the way she said it, Mettaton wasn’t sure he would be seeing her ‘later’.
Series
- Part 1 of HKME