Killer!Sans is very thoughtful but not to the point of feelings, usually killing most of the time, hates being belittled, and generally is a negative character, although killer loves bunnies and had two cat’s before Nightmare killed one. Killer also seems to suffer from multiple personality disorders, as at times (with whatever magic is left) a tiny speck of an eye will appear in his right socket, this is classic Sans trying to get out. This is when he'll have little breakdowns and freak out.