Sans the skeleton is a resident of Snowdin in the Underground, and life as he knows is mostly alright. He had his optimistic, egotistical brother, Papyrus, his mysterious friend in the RUINs, Grillby, the bartender at his favorite place to stay, and many other buddies and acquaintances he'd made over time. But one day, when the friend from the RUINs makes a strange request of Sans, he couldn't help but give her his word and make a promise. However... When he sees the subject of his promise exit the RUINs- A strange, wayward, dust-covered human- Sans questioned whether he'd be able to stay true to his word. (Feel free to leave suggestions for other stories you'd like me to write in the comments! None of the art featured here is mine.)
UPDATE: Uh, so, my headcanons have changed quite a bit from when I wrote this, including Sans' attitude at some points, the Mettaton NEO situation, the Alphys evacuation, and other things. Well, enjoy an inaccurate, probably cringy story! I hope you like it anyhow.
CONTAINS SPOILERS FROM BOTH PACIFIST AND GENOCIDE RUNS
After a horrible situation, I (Y/N) scaped from home to avenge my (sibling). In a failed attempt, I got lost and fell through a hole, in there I found another world... "the underground". I meet many friendly monsters, one, specifically, changed my whole life. Both of us will try to give the monsters the liberty they deserve. And this is how all happened...
(Cover made by me :3)