Undertale Stories

There's only one rule for those capable of AU hopping: never bring a real person into the Undertale multiverse. But, like all rules, it was destined to be broken. | - Error Sans x Female Reader - Young Error - take places not long after he becomes Error - so he mimics his canon version more closely at the start before molding into my fanon version with experience - This intentionally doesn't follow the exact plot of Aftertale either - Achingly slow burn - I abuse Y/n more than necessary (oops) and Error is toxic pre-character development. This isn't meant to portray a perfectly healthy relationship, but show that perhaps even the worst person can change - The friendship dynamic is: bffs that insult each other for fun (while not meaning a word of it) & I include a lot of what's deemed 'filler' content b/w Y/n & Error (y'all just 'hanging out') bc there has to be a solid foundation for Error of all people to care about someone else - Expect a heaping helping of banter 👍 (I couldn't help myself)

Fresh is Admin of the Multiverse!? This can't end well ... or can it? This is an alternate universe - er, multiverse - where Fresh is responsible for the monitoring and disciplining of Players and Hackers as well as hunting down and eradicating any virus or external threat to the multiverses balance systems. Now what's this about some unrad lady called Fate? Welcome to Admin Fresh Verse (AFV for short i guess lol) *** FGoD concept by Harrash6 Characters belong to their respective owners Undertale by Toby Fox **** How the FRESH did i manage #1 in fgod !? Now 1nd in fresh !?! i ... i'm gonna sit down

TW: Swearing and slight gore Y/N reincarnates in the anti-void as a Voice... Will he befriend error or will they make them hate their guts? And will they meet other people? Only time will tell. Hello, this is going to be my first book and idk if it's going to be good so meh :v This story was inspired by transported as a voice by Virus_bOi, I obviously do not own undertale and I don't keep up that much with the fandom, so some personalities might be different, but hey. I can just say that it's a different multiverse ¦ ] The cover image is from Shira Wolfiecute on tumblr

"the healer likes t' sleep. like, a lot." Axe looks at the sole female AND human member of Nightmare's subordinates. She was only ever awake for about 8-10 hours a day, rarely ever 12, it was both fascinating and irritating at the same time. He was damn sure humans would be awake for more hours than that, he even asked Murder at the time if it was normal. Said skeleton didn't give a single care though, his words: "who cares, makes her more tolerable. 'sides she gets her job done." The cracked skeleton just couldn't shake off the feeling that there was more to it than meets the EYE. ━━━PHOTO CREDITS: Whale鯨豚 [@Whale5511] on X! ━━━MOST NOTABLE RANKING: #1 in sansxreader, horrortale, something new and badsanses on 23/12/2025 #1 in undertale on 25/12/2025 #3 in bittersweet on 24/12/2025 #5 in reader on 24/12/2025 #19 in sans on 23/12/2025 ━━━━━━━━━━━━━━━━━━ DATES PUBLISHED: 001 ━━ July 29th of '25 002 ━━ July 30th of '25 003 ━━ August 1 of '25 004 ━━ August 3 of '25 005 ━━ August 6 of '25 006 ━━ August 8 of '25 007 ━━ November 8 of '25 008 ━━ December 22 of '25 009 ━━ December 23 of '25

4 years after monsters came about Ebbot (Y/N) was friends with the Dreemurr children. Being the master dancer that she is can gather her magic to do amazing things. Having been through a lot in the short 19 years of life. She finally meets a handsome monster who knows her big brother and who understands what she goes through. What will happen between these two?

Saitama gets stuck in the Underground. Well, this'll be interesting!

Two worlds. Five and a half gems. Eight and a half monsters. Three humans. One little yellow flower. And an experience that none of them would ever forget.

Killer always knew he would burn in Hell. All the sins he committed. All the death that came with every step he took. Killer was out looking for something new, while Nightmare wasn't around to fix his unstable soul. He meets three little red bastards and their big bad wolf. "eh, you kill, i kill. what's the worst that could happen?"

Born into a world that decided his fate before he even took his first breath, Ryomen Y/N was never given a chance to be human. Feared by his own mother. Hated by his village. Rejected by humanity itself. They called him a curse. So he became one. With nothing left but silence and resentment, Y/N abandons the human world and falls into the Underground-a place filled with monsters who fear the surface just as much as he despises it. But the Underground is not what he expected. Monsters do not see him as human. They see him as something far worse. And within the depths of this strange world, he meets a wandering ghost named -a soul bound to the past, carrying hatred and emptiness similar to his own. At first, they are nothing alike but conflict and silence. Yet as their paths continue to intertwine, something begins to shift. Two broken souls. Two histories of rejection. Two beings the world tried to erase. And in a place where mercy and determination decide fate itself, Y/N must confront a terrifying truth: Maybe the real monsters... were never in the Underground.

Yeah sorry gained an idea on if someone became swap Gaster Also they may be apathetic or just confused on their feelings and MAYBE Autistic, I may be a bit wrong on apathetic or not completely accurate idk yet And it's a huge maybe on the autistic part it might be mentioned at some point or not I usually don't do this kind of story on something like using apathetic and perhaps autistic but i decided I wanted to try. And the maybe confused kind feelings is not knowing what they feel or if they even feel anything and all

Same description as first story Izuku yagi neglected and bullied becomes W.D Gaster and Uses Science to Make his sons Sans and Papyrus

[Cover belongs to me] Error is the (forced) god of destruction, Ink is the god of creation. Both are needed to keep the balance, but while one is loved the other is hated. Ink together with the judges elaborated a plan to finally stop Error. A deadly trap. Impossible to escape even for the feared destroyer. But someone is not following the plan. Things get out of control. Error gets out of control. Although things don't go exactly as planed, and the results are more chaotic than they should. It still worked. Error was finally gone. Lost into the VOID, scattering across time and space. But someone had their eyes on the broken destroyer for a long time, and they were waiting for this moment. Now they can finally act. And take care of their chosen child. ... Error woke up at the sound of his own crying. What? What's this sound? Why can't he speak? Wait, where is he? Why can't he get up? ...Uh? Why is he... so small? ...what happened to him? _________________________________ - Error!Sans is a variant of the character Sans from the game Undertale. Error!Sans was created by LoverofPiggies aka CrayonQueen - This story is inspired by 'Healing what has been broken' by harrish6. Although it happens in a different way, Error will still fall into the VOID. But instead of just falling into a different Multiverse something else happens. - fgod Error concept belongs to @harrish6 - Undertale belongs to Toby Fox Mar 10, 2020

Living on a steady diet of caffeine, sugar, and sheer will is not a healthy lifestyle. But how else can you keep up with teammates that need no sleep, no food, and who expect the same of you? Blue has no intention of falling behind, ever, for any reason. But his lifestyle is starting to show to others. What happens when the enemy intervenes for good?

Dragged from Copper 9 through unknown circumstances and into a mountain civilisation, Crystal faces weirdness and wonders beyond her imagination, as well as mental challenges that push her more than any physical injury can. So the question is...CONTINUE or GIVE UP?

One day, Y/N was playing Undertale. Y/N finished the game, both genocide and pacifist. After the second pacifist ending, you wondered how life would be like IF the monsters actually were real. If the monsters would actually roam around and act as humans. That thought soon changed. ( Book Cover Picture is NOT Mine. I found it on google. Credits to the owner. )

Reborn as the guardian of positivity, you find yourself in a strange new world, uncertain of what it may hold. Navigating it isn't easy with gods like Nightmare and Error trying to strike you down every step of the way. But unlike the previous Dream, you have nothing to lose, and are determined to forge a better path than the soul whom you have replaced. Cover art by the wonderful @Nymara379 on A03 ♡

Reborn as nightmare sans You were, oh, ways angery at something.. no matter how many times you try to destroy it. It still kept coming back. You were reborn as Nightmare, but instead of the beautiful sky, it was full of blood and negative. Dream was stone with tears. You were angry at him but didn't know why.... Then your angery change over time, and you learn to keep your anger in a bottle in your rotten soul. But one day is broke, and your out control and a beast form is controlling you... Waring Self-harm (sh) Body disorder Violence Language Smoking/ drinking Dramatic Angst Trauma Death/murder/ life is unfair Suicide (SU)

it was a hot summer day and everyone want to go to the beach. the meme squad were in other side of the beach while Jr were in other side far way from each other. everyone kinda knows nightmare scary ( not scary) of water. but nightmare had a deep secret from everyone he kept. noone knows except Kevin who seen it in his own eyes. and that demonic chicken knows how keep nightmare secret. so will they fine out nightmare deep secret? or will nightmare exposes himself save everyone? ( the cover is mine )

He was a Gaster with bunny ears, a babybones lost and alone. No home, no food and a thief. The little thief wonders, does he even have a home? Is Gaster actually his name? The little Thief from Daycare for B̸̶̸a̸̶̸b̸̶̸y̸̶̸b̸̶̸o̸̶̸n̸̶̸e̸̶̸s̸̶̸ Godlings Where the creators of our bunny update with no clear plot at all. (Co-writer firehedgehog)

Ashlie has arrived in the Paldea Region, what adventures will unfold for Ashlie, Chuster, and their friends now? (Shoutout to my friend Screaming for the Ashlie render btw) This takes place after the events of "We Will Carry On! Ash Betrayal!"