Secret Six (New Earth-Forty Three)

The X Years
The Secret Six was formed by the mysterious Mockingbird, who assembled six criminals, who were trapped in Old Gotham. Mockingbird would make a deal with the criminals, which if they kept their end of the bargain, he would get them out of Old Gotham. The criminals assembled would be Two-Face, Bane, Firefly, Mister Freeze, Mad Hatter and the Riddler. The deal would involve the six of them doing what they failed to do in the past, which is to kill Batman, who had become a vampire like creature who is terrorizing Gotham. The teams first attempt would end in failure after Riddler and Mister Freeze betrayed the team and disappeared and Firefly was killed.

The group would gain new members in the form of Doctor Light, Catman and Deadshot, who ended up in Old Gotham for similar crimes as the others. Mad Hatter would die during a mission one year before the present and be replaced by the former Rogues' member Top.