Hugh Marder is the CEO of Mecha-North Corp. a recent acquisition of Wayne Enterprises. He is also the villain known as Mr. Toxic.
While dealing with the Dollmaker, Bruce Wayne's company, Wayne Enterprises, ends up aqcuiring tech corporation Mecha-North. One day, CEO Hugh Marder meets with Bruce, prior to the deal's finalization to inform him that Wayne Enterprises has been out bid by Q-Core, Oliver Queen's corporation. Despite the outbidding, Marder informs Bruce that he's decided to accept Wayne Enterprises offer instead, feeling as if it would be more beneficial for both parties involved, despite the lower bid.
He later appears alongside several other upstart criminals as the Gas Man under The Penguin's guidance. He along with the other villains, including Mr. Combustible and Hypnotic, are new to Gotham City and have their money moved to Penguin's vault in his new Iceberg Casino. They are defeated by Batman.
He later reappears in the Gotham Sewers, now going by the name Mr. Toxic. He confronts Batman in Marder's lab in Wayne Enterprises where it is revealed that he is actually a clone of Marder. The original Hugh Marder appears to die when his machine overloads and Toxic escapes. Mr. Toxic later breaks into the morgue and manages to revive Marder giving him a suit to protect him from the radiation. They attempt to repeat Marder's experiment but something goes wrong causing the two men to violently merge. They are saved by Batman and Marder is apprehended.
As the Gas Man he is capable of releasing noxious gases from his wrists. As Mr. Toxic he shows apparent invulnerability to radiation, as well as a high-level intellect.