Ran Yakumo

Bio: An utter genius, and as crazy as any Arkham inmate. That could best describe Grant Walker. A multi-billionaire, he financed a "new world", just outside Gotham called Oceania, and was close to freezing the globe, so only a select few could live inside Oceania. Before he was stopped by Batman, he bribed Mr. Freeze to make him an immortal in the freeze suit. Mr. Freeze, in order to reclaim his frozen wife, did so. But when Oceania went down, so did Walker. Walker was frozen in a huge chunk of ice, which took him two years to break out of. Those two years made him more insane than before. He's currently holding up in Arkham.