At one time, the Underground was a nice place. Despite some vengeful monsters, most were harmless, kind-hearted souls. ... When a human fell down into the Underground, everything changed. The royal family took him in and raised him as their own along with their only son, Asriel. When a fatal accident occurs, and both children die, the king of monsters declares that any human that falls into the Underground shall be killed. While most monsters disagree, and ignore the law, there are a few who will do anything to please the king. ... Years pass, and a human by the name of Katrina falls into the Underground. She is the last soul they need to break the barrier and declare war on the humans who put them in their prison. However, when an unlikely love story breaks out between Katrina and a certain skeleton, her soul is much, much harder to obtain. Will he be able to keep it safe, or will he watch his lover die, just like she watched her brother...?

I kinda fell in love with the idea of Underfell Sans in general. So why not be creepy about it? Enjoy *Eyebrow wiggle*

Hope you enjoy reading this

if you want to find out what happened read it and it is my first story so sorry if its bad

Best ranks: #8 in fanfiction; #1 in undertale; #3 in sans; It was all a dream.....or so you thought.. Edgy: bish how dare u say that was a dreem, it was true af, fite me on dis! *lowvoice* and what im batta do is even more true. *inserts lenny face*

If you need help (if you read lemons) read this!

(Y/n) goes to Mt. Ebbot in search of her brother Frisk. But what she finds instead amazes her.

What happens when a young girl falls into an unknown, cruel world full of monsters and trials to test her abilities. Who would've known one specific monster would end up falling for her?