Dr. Kozaburo Nambu is a high-ranking Interpol executive and key member of the International Science Organization (ISO). Born into privilege as the son of a wealthy businessman who owned a private airfield and bank, he severed family connections after his parents' death and invested his entire inheritance into the Mantle Project—researching Earth's mantle—and investigations into the terrorist organization Galactor. This decision stemmed partially from guilt over orchestrating the separation of his childhood friend Kentaro Washio from his family to facilitate Washio's undercover mission. Physically, he appears as a middle-aged man with shoulder-length brown hair, thin eyebrows, and a thick mustache. He typically wears a light-blue suit jacket over a yellow shirt, maroon vest, navy blue tie, and dark blue pants, with distinctive rimless glasses lacking side stems. Design variations exist: an OVA redesign features a pompadour, longer mustache, glasses with stems, and a bright pink overcoat with pinstripe pants. An unproduced film project initially reimagined him as an Afro-Japanese man with dark skin and a prominent afro, later revising him to a bald appearance with graying facial hair. Nambu maintains a calm, collected demeanor, prioritizing strategic thinking against Galactor. His strong sense of justice and foresight led to the formation of the Red Impulse squadron and the Science Ninja Team. Emphasizing teamwork, he designed the God Phoenix flagship vehicle to deploy Bird Missiles or activate Firebird mode only when all five members cooperated, addressing their initial individualistic tendencies. Academically qualified from Oxford and Cambridge, his expertise spans space engineering, physics, chemistry, astronomy, and medicine. His scientific contributions include developing the team's bird-themed uniforms, martial arts techniques ("Science Ninja Technique"), mecha technology, and pollution-free energy solutions. He possesses significant political influence and fundraising capabilities, securing resources for the Mantle Project. He acts as legal guardian to four Science Ninja Team members: Ken Washio (after his mother's death), Joe Asakura (rescued from BC Island following his parents' assassination by Galactor), and orphaned siblings Jun and Jinpei. He established Jun's Snack Bar J as their operational base and living quarters. Ryu Nakanishi, the sole member with a biological family, did not require guardianship, though Nambu accommodated his familial obligations. Nambu's relationship with Ken is complex due to his concealment of Kentaro Washio's survival and transformation into Red Impulse. Similarly, his rescue of Joe involved fabricating the boy's death to protect him from Galactor, unaware of Joe's parents' affiliation with the organization. Nambu experienced personal losses during wartime, including the abduction and killing of fellow scientists. A significant professional rift occurred with colleague Dr. Demon, who joined Galactor after losing an ISO directorship to Nambu. Their attempted reconciliation ended tragically when Demon, manipulated by Berg Katse, committed suicide during a confrontation. This fueled Nambu's later insistence on redeeming compromised scientists like Meckel, ordering his rescue despite Galactor ties. His career trajectory saw him assume leadership of the ISO after Director Anderson's death. Later, he is killed during the conflict, leaving behind a reincarnation device. His legacy includes mentoring the engineer Kamo, who succeeds him as the team's advisor. International adaptations alter his role and name—notably as "Security Chief Anderson"—but these deviations do not reflect his canonical narrative. The 2013 live-action film retains his character as the team's coordinator.