Killer!Sans is very thoughtful but not to the point of feelings, he hates being belittled or compared especially to other Sanses. Killer also seems to suffer from some type of personality/identity disorder similar to DID. He'll have little breakdowns and freak outs when he's beginning to feel again and is reminded of the pain he's caused. He's hard to read and often unpredictable, his emotions are often suppressed or out of control, when they are regulated