Y/N is an Ultima but she is also a soul mix. A soul mix is when two soul types combine and become one being. She is a mix of CHAOS and CORRUPTION. The strongest soul types other than Determination and Fear. Y/N was used as a weapon in a war. The Children's war to be exact. She has become emotionally drained since then. She hopes that the bitties will help her become more emotionally active. And they do...

Keys (Y/N)-your name (F/C)-favorite color (LS/N)-little sisters name (LS/FC)- little sisters favorite color

Warning! There is a chance that there will be spoilers for the pacifist run of undertale. I recommend finishing that before reading this. There won't be any spoilers for the no mercy run, so don't worry about that! Also, don't worry about anything NSFW/lemon if that's not what you're into-there won't be any of that here. You're a human that's fallen down into the underground. You've decided that you'll stay instead of going home after fighting Asgore and sparing him. Now, you had made some great friendships while in the underground-but one of those friends in particular was one you'd like to be a little more than friends with... Aaaa an X reader fic! I haven't done one of these before, but I hope you still like it!