This is Killer Sans or just Killer. He's very flirty with a lot of people and can be very annoying at times. (You are Nightmare) Nightmare is basically a black octupus, he is a bit mean and controlling. He also gets a lot annoyed by Killer.

Ink Sans: he is the protector of AUs and not the creator of AUs as many people think. He has vials which contains emotions for him, but when he doesn't have his vials, his pupils will turn white which means that he has no emotions. Ink Sans will often mess with Error Sans which usually results in Error Sans attacking Ink Sans because of it. You:any personality, gender, name, or anything else