Joe Umitsubame pilots the submarine unit Gekiga Marine as one-third of the combining super robot Gekiganger III. Headstrong and impulsive, he repeatedly clashes with teammate Ken Tenku over strategy, their heated rivalry tempered by unwavering mutual respect and camaraderie. Both nurture unrequited feelings for Miss Nanako, further complicating their partnership.

During a critical battle against General Masaka, Joe engineers a tactical sacrifice, deliberately letting his machine be impaled to create an opening for Ken’s counterstrike. His apparent death defies genre conventions by centering his agency in the narrative over traditional pilot arcs. The loss fractures the team, prompting Gekiganger III’s upgrade to Gekiganger V and the recruitment of a new pilot.

Joe resurfaces in the climactic showdown against Emperor Hyperion, returning from assumed demise to support the upgraded team—a resurrection mirroring the series’ thematic defiance of cold logic through raw passion. A late-series revelation ties him to extraterrestrial origins via Sapphire, yet he steadfastly claims Earth as his home, cementing his allegiance to humanity.

His influence persists beyond combat; his choices and convictions ripple through the narrative’s exploration of how in-universe fiction molds societal ideologies. While his character design and role homage 1970s super robot archetypes, his story subverts those traditions—challenging expectations through calculated sacrifices, unexpected survival, and a legacy that redefines mecha tropes.