Professor Arthur Manhart was the lead researcher at Dunhill Laboratories.
Gaining funding from Mecha North-Corp and later HM Industries, Professor Manhart aided Hugh Marder and Mr. Toxic in their mad endeavours. However, when the incidents they caused resulted in lives being killed, Manhart used contacts up at the City Council to get Dunhill out of the mess. After meeting with Bruce Wayne, Professor Radium attacked Manhart and threatened to destroy Gotham City in his projects. However, Radium was defeated by the Batman.