The Joker is helping Batman uncover the secrets that exist in the underbelly of Arkham. The Deadman finally enters the Man-bat to give Batman the key that will unravel the secrets that are driving the Bat batty.
Neal Adams is certainly challenging us to uncover what could be the secret that requires so many players to guide Batman to his destination. What ever it is it can not be told directly to batman; Batman needs to uncover it by himself.
There were a few moments reading this comic that I really felt like Neal Adams was playing was testing our patience. I particularly did not like the Joker panels on page 13. Somehow it felt like an attempt to really confuse us. It turns out that the Deadman has entered the Joker in order to guide batman to Arkham.
I would be lying if I said that this series is making any sense. I still await enlightment.