Underswap Stories

Long ago, two races ruled the Earth: HUMANS and MONSTERS. One day, war broke out between the two races. After a long battle, the humans... wait no, the monsters were vic...

Blue is sick of being treated like a child by his friends and family. He shoves down his negativity in order to stay 'happy' like they want though. Nightmare has had eno...

This story takes place after the player vanishes from their fight with the bad time trio aka Sans, Shift, Stretch. The three got stuck there for a very long time until a...

This story will contain allot of violence, cussing, smut and other things... Blueberry used to hangout with Ink, going around visiting different AU's ..However when they...

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...

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...

Moved from AO3 because of reasons! "You are the only maid (or worker in general) that serves for the Skeletal Household. It's a skele-ton of work, but you manage by...

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 from our world was reborn as fellswap sans? But an accident when he was young leads to becoming blind for a long time and papyrus feels guilty about not...

Completely female readers unless a request asks different. That's...really about it, enjoy!

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...

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...

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...

Y/N, meets a new coworker that changes her life forever. A monster, doing his best to make a living after moving out of the underground. Sans is this ecstatic, cheerful...

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...

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...

**PLEASE NOTE** -Cover art does not belong to me, I will only take credit for the stories, I do not take credit for characters. -I will not do any lemons -This is my fi...

When your sibling Chara goes missing you fear the worst, but life takes a surprising turn for the better when they release the monsters trapped underground. Living this...

Official remake of Ulty: Creation of a monster A story that starts from Dusttale and goes around the AUs, completely transforming our protagonist English is not my nativ...

(As far as I know, no one has made a story about naturetale like this so..and the only reason why I writing one like this is because of fatal error part 5? Or part 4, go...