Villainandherodeku cerita

I have been creating this story in my mind for a very, very long time. it was when Izuku was little his dad gave him a shot and made him see another version of himself, a villain version of himself. he used to be close with him when he was little, but when he did took over his body, he made him vanish. a few years later.. he returned.. but differently then expected.. what will everyone do? whats different about this villain version of izuku? what will happen?