Villain and the hero almost always have a great deal in common. They both have a backstory of pain. You will normally see the villain with some sort of scar on their face or a limb or something that says they've been hurt in the past. The hero has also been hurt. They had a challenging backstory as well. The difference is they responded differently to that pain and suffering. The, the hero said, I am not going to let this happen to anybody else. I'm going to take the villain down. The villain says, I'm going to seek vengeance against the person who hurt me. I got hurt. I'm going to hurt other people now too.