- "Imagine a group of brilliant outlaws like yourselves, each selected for their unique ability, all working together as a team. Imagine the synergy. Imagine the impact. Gotham would tremble before you."
- —Theo Galavan to the Maniax[src]
Six inmates of Arkham Asylum, Richard Sionis, Jerome Valeska, Aaron Helzinger, Barbara Kean, Robert Greenwood, and Arnold Dobkins were abducted by Tabitha Galavan on the orders of Theo Galavan. They were later offered the chance to become a team that would make Gotham City tremble, by Theo.
Exploits as a group
The Maniax raided Yellen Shipyard, stealing a refueling truck out of a hundred service vehicles. They also kidnapped seven employees of the shipyard, and dropped of them off the Gotham Gazette building to spell out a message on the ground. The Maniax later attempted to burn a Gotham City High School bus, full of cheerleaders, though they were stopped by Detective Gordon. Disguised as GCPD officers, the group later went into the GCPD department, shooting it up, and killing several officers.
Jerome and Barbara performed a magic show at the Gotham Children's Hospital gala. After performing a few tricks, Jerome killed Deputy Mayor Harrison Kane and some unnamed henchman opened fire. As Leslie Thompkins contacted Bruce of the situation, one of the unnamed henchmen kidnapped Thompkins and Barbara placed her on the wheel of death while Alfred Pennyworth was subdued upon defeating some of them to protect Bruce Wayne. Jerome contacted Gordon and told him he'd have 10 minutes to give him 47 million dollars and a helicopter to get away. Theo emerged, telling him if he were to take a hostage, he should take him and let everyone free, though Theo was knocked from behind by Barbara. Jerome later teased a guest at the gala, shooting him with a gun loaded with water. Soon after, he told the gala it was time for their first official victim and Jerome called for Bruce (who was trying to get away with Selina Kyle). Jerome told Bruce to come out or he'd kill Alfred, which Bruce agreed to. Jerome held Bruce with a knife on Bruce's throat and Gordon came out as a brief fire fight ensued. As Jerome held Bruce, he teased him, asking him if he wanted to "boost" the ratings. With help from Selina, Gordon entered the building and freed Alfred where they subdue Jerome's unnamed henchman and hold Jerome at gunpoint. Before Jerome could slit Bruce's throat, Theo told Jerome to stop and stabbed Jerome in the throat. Theo told Jerome it was not what they rehearsed and it was time for him (Theo) to be seen as a hero. Barbara then escaped through a magic curtain.
Following the deaths of the other Maniax members, Barbara ended up in an induced coma, which she later woke up from in Arkham Asylum's medical wing, and Aaron was subsequently recaptured and sent back to Arkham Asylum.
Jeri's nightclub that Bruce Wayne visits shows that they are copying the Maniax's legacy and have footage of their actions shown, as well as mugshots of them flashing on the walls and also some of Jerome's quotes. Members of the nightclub are also shown wearing similar straitjackets the Maniax wore when attempting to set fire to the school bus.
- Robert Greenwood (deceased)
- Arnold Dobkins (deceased)
- Jerome Valeska (resurrected-then re-incarcerated)
- Barbara Kean (re-incarcerated - then discharged)
- Aaron Helzinger (re-incarcerated, presumed deceased)
Non official member
- Richard Sionis (deceased, killed by Tabitha Galavan)
- "Rise of the Villains: Knock, Knock"
- "The Last Laugh"
- "Wrath of the Villains: This Ball of Mud and Meanness" (images & archive footage)
- "Mad City: Ghosts" (mentioned in archive footage)