I don't know much about DID, so I apologise if I say something wrong.
Harvey Dent and Two-Face | DID headcanon.
Two-Face always existed. He wasn’t created when Harvey had the accident, he was always there. Harvey and Two are part of a system, which Harvey being the host and Two being the protector. Harvey doesn't know he has always been part of a system. He always lived his life like just a regular person. But Two was always there. Before the accident, they had similar enough personalities so people wouldn't noticed the difference between them. Harvey was the host, so he was the one who spent most of the time talking with others. But Two is the protector, he was the one supposed to make sure the system was alright. When the body was kidnapped, he switched place with Harvey. He was the one that lived the accident, and then it changed him. That's why he is like he is currently. The accident affected more than just him, of course, but he took most of the blow. The reason why Two became a rogue is because he's the protector. He was supposed to protect the system, but he failed. He failed, and the system suffered. So now, he is living under the rule that if he is the one pointing the gun, no one will point the gun at him and Harvey and the system anymore, and that way he keeps everyone safe. He isn't evil, just desperate to keep what is his safe.













