Manabu is a 12-year-old war orphan surviving on Earth after the planet's conquest by the Zaar Empire. An alien invasion caused widespread destruction, claiming his parents and forcing him into a makeshift community with other orphaned children. He shares the trauma of loss and displacement common among Earth's youth after the invasion.

Manabu possesses an uncanny knack for technology, making his skills vital to his group's operations. His expertise in mechanics and engineering aids in maintaining and developing weaponry at Doctor Earl's hidden base. His consistent competence in managing the base's technological systems earns Doctor Earl's trust, leading to Manabu overseeing technical operations.

A key contribution is his invention, Gamelot, a specialized vehicle deployed on missions. Younger orphans like Ochame and Jiro frequently pilot Gamelot, with Tanosuke occasionally operating it. This invention bolsters combat efforts alongside the primary robot Daltanious. Manabu's expertise also drives large-scale projects, including rebuilding a ruined city through ingenuity and resourcefulness.

As a core member of the orphan group, Manabu adopts a support role focused on technological and tactical aid, not direct combat. His development centers on evolving from a displaced orphan to someone integral to the resistance, applying his intellect strategically. He joins group missions focused on survival and rebellion against the Zaar occupation, his technical inventions providing crucial practical functions.

Manabu's interactions with the group reflect shared experiences of loss and resilience. His relationships with other orphans, including Kento, Sanae, and the younger children, show them united in rebuilding and resistance. His consistent role is that of a technical specialist, contributing to group objectives through innovation and maintenance of their technological assets.