What would Batman do if he discovered a secret side/ sub culture of Gotham. Essentially learning that supernatural creatures roam the city and are pretty much in charge with supernatural royal families that run the show. Essentially Batman learns everything in this world is upside down with complex rules, traditions and Joker is the actual king albeit a tyrannical ruler that keeps any and all the supernatural community members whether they are harmless or not under his thumb. Batman even learns some of his enemies that are considered in sane are actually supernatural themselves like the dummy Scarface actually being alive and Two Face being possessed by a demon.
Ultimately things get a lot more dangerous for Batman as he finds out Joker knows his identity and even tells him right after showing up at Batman's own home like he's there for a casual visit "You know Bruce this whole fight we've had going on has been fun and all but now that you know the truth about me and the truth about what goes bump in the night in Gotham I'm afraid that the party is over. So you will either play ball or I can make life very difficult for you. Oh and I've already pulled a few strings so don't bother asking Zatana, Spectre, Jason Blood, and who ever else you know in the magical community for help because you've been officially black listed."
Then Joker takes Batman on a tour of this secret side of Gotham as a way of showing just how much influence he has and even executes someone in front of Batman. How would Batman react to such a revelation?
On a side note do you think Batman would really indulge Joker to this extent?