Undyne Stories

This story takes place after the events of the pacifist ending of Undertale, where all the monsters have already left the underground. However, that won't stop problems from starting again; Frisk and his friends will have to face a new threat. DISCLAIMER: This story is based on the fact that the first human fell underground in 2015 and the last in 2060. Here, Deltarune is a sequel to Undertale; therefore, Posttale is not a copy of TobyFox's creation, but an adaptation, or what is also called an "AU." Because of this, there will be things that are different from canon and adapted to my personal preference, with no intention of disrespecting anyone; for example, the gender of the humans: Kris: M Chara: F Frisk: M Don't like it? You can leave. Understood? Great. Contributors: @Fwrevy #Deltapad • Undertale and Deltarune are property of Toby Fox. • Images used in the story are property of their respective owners or made with AI. *#27 in the "Undertale" category 6/13/2026* *#3 in the "Deltarune" category 3/3/2026*

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

It's a fall into darkness... a world of starving monsters. All that would do anything to survive. And that includes catching a human like you. Horrortale. Inspired by Undertale, based on the Horrortale universe. Credits to Toby Fox and Temmie Chang for their respective characters and Sour Apple Studios for creating Horrortale. Just a small warning that there are some grusome imagery. Continue reading only if you're okay with it! (Art credited to it's respective artist.)

Sans and Papyrus were just trying to have dinner. They didn't expect things to blow up (literally). Now they have a destroyed machine and a young babybone that they suspect as a Shifter. Where did they come from? And who's life privilege they need to remove? Because this babybone is clearly been abused or worse. Now then, where's that parenting books Sans been storing since Papyrus a babybones, he's definitely need a review if they want to keep the kid from getting killed. At least the kid's adorable...

I found some books on Undertale reacting to be completely abandoned and decided to do it myself.

i hope you like it! There was a girl Who fallen down the great abyss. She danced,she smiled,she laughed,she loved.. She met Toriel Sans Papyrus Monster kid Undyne Mettaton Aasgore And Asriel and chara She had great friends!

Short Summary: An Undertale AU, which is a crossover with my The Last Star Seeker series. Long Summary: A young human girl falls into the underground. After being caught and taken up to the castle, they face their judgment. Little did everyone know that this girl had magic like all monsters. The king decides to SPARE her in hopes that she could break the barrier without having to take more souls. Years pass, and Astrella hasn't figured out how to break the barrier, but when she sleeps, she's given messages that shake her to the bone. So, with the help of a funny skeleton, they solve the mystery together and maybe more about themselves too. Yes, this is an oc x canon story 👀

Each run started and ended the same. Nothing changed. Until one RESET broke the human's world. The monsters remember deaths from a distant past. They remember the Angel bringing its wrath upon the Underground. The Angel was unstoppable... save for its own curiosity. But that never meant monsterkind could stop trying. Lest... we forget.

WARNING: This is not the official book adaptation for the 2015 video game Undertale. All characters, settings, and original plot all belong to Toby Fox. If you have not played the game, I would kindly remind you to play the video game. (It's one of my favourite video games). This is only a fan-fiction book for my writing skills and to deepen the Undertale themes from the game.

Papyrus, Undyne, and Alphys are hanging out in Waterfall on Halloween talking about their plans for that day. It doesn't go as expected. (Was a oneshot, is now continued and finished!)

Christian Bale receives a fan letter from Papyrus Undertale The Skeleton one day telling him he was a huge fan of his movie American Psycho and his role as William Afton in the Five Nights At Freddy's movie. Papyrus asks if Christian would be willing to become friends. After some consideration the two become very close friends. However, soon enough some stronger feelings arise. While monsters have become accepted in the human world, romantic relationships are still frowned upon. What will the pair do to keep their love a secret? Will the world learn to accept this dynamic or will they be banished back under ground?

After going exploring up a mountain that 7 prior humans have been found missing after adventuring, you trip on a conveniently placed twig. You trip on it and fall into the underground, home of all monsters after the war. As you go through monsters with fights and friendships. But, something feels off about some of the monsters... This is an undertale recap story. This is why interpretation of what happened but it's mainly undertale pacifist in story form. There will be some ocs but not many. My oc braylyn (3rd fallen human, bravery soul) And my friend needlings oc Cloudy (6th human, Perseverance soul)

YOU WILL ACCEPT EVERYTHING THAT WILL HAPPEN FROM NOW O- ... WHAT'S THIS? THERE SEEMS TO BE A MALFUNCTION WHILE OPENING THE GAME OPEN IT ANYWAY? NO MATTER YOUR CHOICES DON'T MATTER ... OR DO THEY? ~ This creator been waiting for a crossover between Undertale and Deltarune for decades, which is actually days. The creator apologizes in advance if she ruins the fandom even more. She's a person who is always dying for a crossover, wanting to to know what happens if two separate worlds clash together. ~ There are rules that need to be followed in this book: •In requests, no smut is allowed, but fluff is acceptable •In requesting, you may request more than 3 characters, for example, (Undertale Character) meets (Deltarune Character) and (Deltarune Character). For your information, you can choose as many characters as you please, but because of the book's save file, they may remember each other from other chapters. •When requesting something, give little information of the story you would like to read, for example, if you wish to make these two characters meet, you want them to bump to each other. •The book has a limit, and will stop it there's no requests. •Curse words are acceptable, but minimize it. •Jokes, memes and are acceptable. •Ships are minimized. •This book is suitable for ages 13 and above because of bad words. •Bringing a dog to this book will result in the book mistaking it as the true creator, it will then have an effect to the chapter. •Criticism is allowed. •Minimize arguement in the comments, or there will be consequences. •Book thieves will be punished. •You can pick any genre of your pleasure when requesting, but do not request what the creator cannot do. •The true creator of both universes is Toby Fox. •Other questions can be answered in the comments on the first chapter. ~ *If you do not understand *Do not worry *For that time *Is fast approaching

i'm trying to write more stories so...here we go

Abandoned on Mt. Ebott at the tender age of five, young Harry's unsurprisingly died, but Death's always had a weird relationship with his variant... Meanwhile, before Flowey's revival as souless talking flower, Sans makes a discovery under the mound of snow, Papyrus has always wanted to be a big brother anyways. *Edited Summary (29/09/2025)

[Written by Júlio] The League of Villains was severely lacking in resources and manpower. One day, Dr. Garaki instructs them to travel to Mount Ebott, which is surrounded by legends that humans who try to climb it never return. In an accident, Himiko Toga falls into an abyss, separating herself from her teammates. Upon waking, she discovers a new world, and that the reality there is different from what is seen on the surface. Will the blood lover continue her journey back to the surface continuing with her violent and bloodthirsty instincts or will she try to find a pacifist way to continue? (Boku no Hero Academia X Undertale crossover) [Note: The cover was made by me, but with art from other users. Toriel, Papyrus and Sans art by: kamezaemon Chara art by: DlaBlo di dante Flowey art by: CoraWARD Undyne art by: Maximillian Schmidt Asgore art by: Donna and Katreal Alphys art by: I don't know, and if anyone knows, please tell me.]

Monsters have lived under that damned "Mt. Ebott" for as long as he could remember. But finally, they were out. There's a whole new world just waiting for him... And maybe even a certain someone.

Your favorite skeleton is back at it again... and again... agagaagaag Sans has had enough. Everyone is at the surface, holding their own jobs and lives. But... Sans can't ever let it fade from his mind. The dust. The cries. Watching the screen with Alphys as a child just rampaged in the underground. He is going to snap. He is mad. He is sad. He can never forget. Cover is NOT mine, find it online if you want ::Rights for the original concept and media 'Undertale' are all under the jurisdiction of Toby Fox. All other workings are done by me.::

After Y/N's Mother died, her little sister was the only thing keeping her going. However, one day the two of them decide to run away from their abusive Father. Y/N's sister loved the legend of Mt. Ebbot, so she wanted to explore up there. Finding what they thought was the entrance to the world of monsters, the younger sister fell in. Not being able to jump in after her, Y/N was taken home by her Father, only to run away again and follow her sister into the hole. In this strange new realm, Y/N finds herself doubting she will ever find her sister after many attempts at doing so. What will keep her motivated to live, and where is her sister?

Some Undertale oneshots. You can request an xReader or a character x character. I don't do much but angst and fluff. My first xReader, please send me feedback. Hope you enjoy! All credit for the undertale characters goes to Toby Fox. I don't own you either, btw.