Batman #7 visits Patient Ten and learns a secret
There is a man in Room Ten in Arkham Tower. He floats in a tank. And he has reached out to talk to an old friend. Batman confronts the Joker again in Batman #7.

There is a man in Room Ten in Arkham Tower. He floats in a tank. And he has reached out to talk to an old friend. Batman confronts the Joker again in Batman #7.