Underswap Stories

[Prolong] My name is (Y/N). I have experienced many resets, so many I have lost count. The only people who remember are Sans, Flowey, and me. The monsters down here are...

Nightmare found a young child a long time ago. When they fell into a coma it sent him over the edge. several hundred years later the child wakes up in a castle of darkne...

Note to self: Never make jokes about getting reincarnated into a video game character because it'll actually happen. Welp too late to go back now, considering I'm alread...

Sans and Papyrus were your best friends until randomly they just cut off all contact with you. This went for everyone else in your life so it didn't really hurt that muc...

Y/n was and/or is a very sweet child, unfortunately for them they weren't treated very well by their mother or father, Y/n was abused and didn't have anyone. Fortunately...

What if when gaster fell into the core and his soul shattered...what if he was reborn as a human that had knowledge from there first life from our own world? What if...g...

what if someone in our world becomes US!sans also known as blueberry?

What if someone is reborn as Error? What if they aren't so bad? What if they're suffering in silence and keeping their job a secret for fear of hate? How will Ink react...

He knows he'll be dooming them if he falls, but he's tired, his body is breaking apart, held together on a higher being's whim only. He wonders if there'll be another to...

So harem book of Charas and Frisks x male reader but real description is below this. The only one of his person in all universes is part of Undertale with an OP powers b...

Why am I making this? Why are you reading this? Why are we here?

This is an Undertale book Criminals have always littered the streets causing a mess and breaking the law. But what happens when criminals Fall in Love? This includes all...

I found this pictures on deviantart,pinterest,google and Frans Amino

!! Long Chapters !! 1000-4000 words each! **This book will be continued by another person so check the A/n at the end of the book to go to their continuation of this!** ...

When made by his father, the god of death, he didn't know his purpose. All he could do was kill things on accident...he didn't mean to kill them, he just wanted a friend...

What if someone died and became the tree of feelings from dreamtale? Well things won't stay the same, that's for sure. (Different everything etc, different personalities...

Hi guys! First of all I should mention that the story pic isn't mine and of course Fellswap belongs to its original creator. A young hiker, Y/N gets lost and accidental...

Part 2 of AU Undertale One-Shots. I wright fluffy hurt/comfort oneshots. I do take request if I am able to do them. No lemons but there will be romace and small makeout...

Y/n L/n. A special human with a special SOUL. Yes, her Soul Trait is something new. But other than her SOUL trait she has another secret. One day, while she was at the...

A passive soul from our world is reborn as a Sans who has to take action, Ink. As willing as a soul who was forcefully reborn they take charge of their baby of a multiv...