Changmin has a sweet, calming and charming front, with violent tendencies that no one knew of. Wrong him once, and he could switch into a complete psycho. His biggest secret is that he actually ended your sister. He and your sister were in a toxic relationship, she was abusive to him and one day he snapped. He would never tell you, until you confront him. He secretly hates the fact that you are desperately trying to find the murderer. He would stop you at all costs if you went too far.