Genzō Umon serves as a scientist specializing in outer space research at the Photon Power Laboratory, operating as the subordinate and right-hand man to Professor Gennosuke Yumi, also recognized as Yumi's kōhai. His scientific focus encompasses the study of alien technology. He becomes the adoptive father to Duke Fleed after Koji Kabuto discovers Duke suffering from amnesia in a desert; Umon provides shelter and bestows the Earth identity "Daisuke Umon" upon him. Within the laboratory, Umon exhibits pronounced enthusiasm for extraterrestrial science, particularly concerning Duke's origins and Grendizer's advanced technology, often engaging in lengthy technical discussions that colleagues like Sayaka Yumi sometimes interrupt.

Umon's perspective on Duke and Grendizer contrasts with Professor Yumi's cautious stance. While Yumi voices concerns about potential threats from alien technology and Duke's non-human morality, Umon adopts a welcoming and optimistic approach. He advocates studying Grendizer's technology to bolster Earth's defenses and supports reverse-engineering efforts to enhance Mazinger Z, establishing a cynic-idealist dynamic with Yumi in their scientific and ethical viewpoints. Following an attack injuring Professor Yumi, Umon assumes temporary leadership of the Photon Power Laboratory. In this role, he oversees operations during a crisis involving Vegan Empire aggression, managing strategic research initiatives and coordinating defensive efforts alongside the pilots of Grendizer and Mazinger units.