Pure Soul (Gaster!Sans x Reader)

Chapter 1: Invasion

Your POV

The war...

It was so horrible. And quick. Why did it have to go like this? I'm currently in one of the safest human camps that I could find. The others were eradicated by the monsters.

I didn't blame the monsters, though. It was the humans who trapped them Underground. But I never thought the monsters would start such a horrific war. Most of the humans were dead, and I have not seen a single monster spare a human.

Little did anyone know, you could be the key to saving either race. You only wanted to tell them that when it came down to it. Your soul is the purest soul. Not only do you have a special power called 'Reset', but you also had other powers. Ones that you sometimes didn't know how to control. Luckily, no one knew that fact. You sigh and sit down in an alley. The humans had made camp in an old, run down town that you didn't remember the name of. You felt...

Well, not safe, but close enough to it.

But then a sudden blast caused you to nearly jump out of your skin. Your head whipped to the side and you glanced around in alarm as a voice boomed over the sound of yelling and screams of unpreparedness.

"Check them all. If they don't have what we want, you know what to do"

You, on instinct, get up and rush off in the opposite direction, but not before you hear a voice murmur darkly.

"I can almost feel the magic... I think this might be the one!"

You dash off and find a building with a lock that was broken. You shove it and, luckily, find that no one was in there. You climb the stairs to near the top floor, so that if they came from the bottom, you could run up, an if they came from the top somehow, you could run down.

You ignore the distant screams and cower against the wall. You knew that the monsters were too overpowered for the humans to defeat them. You wonder how they even got them trapped Underground in the first place.

Suddenly, you hear footsteps climbing the stairs. You freeze briefly, then see a head poke around the corner.

It's a monster, of course. This one was furry - fully white and small little claws on his hands. He had large horns poking out of his black and aqua hair, and a big fluffy tail.

You don't get enough time to examine him further as you get up and dash upstairs. That was a close call.

You climb a few more steps and find yourself at the top - unintentionally on one of the biggest buildings. You look down and see the male monster leave the building and look up at you. He immediately looks away as a skeleton comes over and starts talking to him. You can't help but watch, peering over the edge. You couldn't hear them, but you could see a bit of the skeleton. He has a crack on top of his head and wore a fluffy black jacket with some sort of symbol on the sleeve. You couldn't tell what it was and you squinted at it, trying to figure out what it was.

Suddenly, he looks up at you. The furry monster is shoved to the ground and shouted at, before the skeleton dashes into the building.

Why, oh why, did you have to choose the tallest building?!

You look around for any means of escapes and luckily find one. You head over to some metal stairs and put a foot on them. They creak a little, but you take your chances. You grab the railing and start heading down.

"Hey! Get back here!" You hear a shout behind you, followed by running footsteps.

You ignore it and start climbing down the stairs. You hear the skeleton climb down the stairs after you and him shouting orders into some sort of walkie talkie thing.