Duke Fujisaki is the chief mechanic of Oblivion Bay, primarily responsible for designing humanity's combat mechas, the Rogues. His engineering expertise drives the development of the Megaton-class Rogues aboard Shelter Ixia. Fujisaki invented a novel twin-drive engine system requiring dual pilots, specifically implemented in the red and bronze Megaton-class Rogue, Maximus. This system allowed pilots Jun Kirishima and Momoka Saotome individual control of each drive engine, enabling advanced maneuvers like the Over Drive Run through coordinated boost timing.

After Maximus sustained severe damage during Ixia's takeoff and Jun Kirishima sacrificed himself to protect Momoka, Fujisaki oversaw the unit's extensive repairs and upgrades. This resulted in the enhanced model, Maximus Blaze, which the duo continued to pilot for the remainder of the conflict. His role encompasses the critical technical design and maintenance of these specialized combat units.