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. Killer also seems to suffer from multiple personality disorders, as at times a tiny speck of an eye will appear in his right socket, this is classic Sans taking over. He's friends are Dust/Murder, Horror, and Insanity.