Dr. Nambu, the creator and mentor of the Science Ninja Team who raised Ken Washio (Gatchaman) and Joe Asakura (Joe the Condor) in their original world, becomes corrupted in an alternate universe after seizing control of the powerful Nexus technology. Following the deaths of four Science Ninja Team members under his command in this world, his morality erodes, leading him to fully embrace the Nexus's power for his own goals. His objectives shift toward imposing absolute order through authoritarian control, aiming to create a new superhero team operating solely under his direction.

Corrupted, he murders the alternate Ken when Ken attempts to stop his plans. This act sparks a prolonged conflict with Joe, the sole survivor of that world's original team, who becomes determined to stop Nambu at all costs, advocating lethal measures after witnessing Ken's death. The core conflict stems from Nambu's use of the Nexus, which poses a profound threat to reality by endangering dimensional stability. His motivations combine grief over his team's loss with the Nexus's corrupting influence. His relationship with the original Ken is complicated by Ken's struggle to reconcile this version with his mentor, creating a moral dilemma about confrontation.

Visually, this version retains 1970s design elements, including his distinctive mustache and suit style. He employs advanced Nexus-derived technology and weapons to enforce his control over the parallel Shibuya. His trajectory depicts a fall from trusted guidance to tyranny, fueled by power and loss. His role culminates in a confrontation challenging the protagonists' ideals of justice and personal bonds to him.