You've met Killer a couple of time. Even though you knew he was a heartless psychopath, deep down you knew he just needing some fixing. So that's what you tried to do over, and over, and over, again and again until one day... his facade breaks and you ask him what he truly wants.

"I... I want my brother back. My friends. My old life. I want to be 'SANS'." He cries, his soul turning into an upside down heart.

Everything was going well until you felt an unusual amount of negativity in the air. Nightmare's coming soon to revert his soul back to his maniac self.