Now that Batman is a zombie he eats the brains of the bad guys. He is still a good guy, but people don't like him and want to be around him anymore. He turned Joker into a zombie, so he would be able to fight his arch enemy forever. They will never die, so the fight between them will never stop. They are eating peoples brains, and Joker keeps killing innocent civilians by eating their brains. Batman is trying to find an antodote for the zombification sickness, but he hasn't figured it out yet. Joker does not want to recover from being a zombie he wants to stay as a zombie. Batman and Joker were fighting when there arms fell off rom punching each other they both got there arms and left the seen to go get their arms reatached.