1.Riddler
I see the Riddler as a cop who becomes obssessed with Batman. He could even become so mad he would join the mob, while still getting to work with the cops, giving info to the mob. He may even find Batmans identity.
2.Black Mask
Black Mask may emerge as gothams next mob leader. Black Mask is known to target Wayne corps and wreak havok. Black Mask will probably be targeting the Batman. hiring an assassin to take him out.
3.Hush
Hush is a crazy who hates the Wayne family for saving his mothers life. Hush would probably be hired by Black Mask to kill Batman. My theorie is that the riddler will tell Hush mho batman is, and kill alfred but only injure Bruce.
4.Bane
Bane could also be hired by Black Mask to kill Batman. I have a felling he will BREAK batmans back,(FOR ALL THOSE WHO READ KNIGHTFALL)
5.Penguin
Penguin could be used as the new district attorney, who takes over Gotham. he could also lead the Mob at the same time.
6.Two-Face
Two-Face could come back and escape from Arkham Asylum. and try to reveal himself to Gotham, while leading the mob.
Tell me what you think!!!!!!!
MY PICKS- Riddler, Hush, Black Mask