I wouldn't know precisely about the game and Arkham Knight's Joker because I'm waiting for the game to be sorted out and updated for pc. I don't have the computer for it or money for a xbox or a ps4 anyway. I'll be playing it once I have a new graphic card or my boyfriend gets it, I'll be able to at least try it out when he does

But did'nt Nightwing take Batman's place for a short while before Bruce Wayne went back to being Batman in the dc universe? I seem to remember that.