This page talks about the antagonist in Choudenshi Bioman. For the Awful Hospital character, visit Doctor Man (Awful Hospital).
Doctor Man is the supreme ruler of Gear and an inventor who attempted to conquer the entire world. He is the main antagonist of Choudenshi Bioman.
Doctor Man was actually a human named Dr. Hideo Kageyama who experimented on himself to accelerate his intelligence, only to have his body rapidly age in the process. To extend his life, Kageyama converted himself into a cyborg with a deep disgust for humanity, planning to conquer the world with his army of Mecha Clones while remaining alive long enough to find a worthy heir to his empire.
When his true origins are revealed, Doctor Man countered the coup with a Mecha Clone copy of himself and later reprogrammed the Big Three and reorganized the empire. With his empire dying, he goes and fights the Biomen with King Megas only to be defeated. He activated the Neo Bomb but he ended up stopping it when his son and the Biomen prodded him eventually resulting in his death.