OVA
Description
Professor Gennosuke Yumi serves as director of the Photon Power Laboratory, succeeding its founder, Dr. Juzo Kabuto, after his death. He is a middle-aged man with dark hair, a mustache, and glasses, consistently seen wearing a white lab coat over a shirt and tie, though he dons a blue suit for formal occasions.

Calm, dedicated, and strategically minded, Yumi prioritizes the laboratory's mission to advance photon energy for peaceful applications, actively opposing its militarization. This principle compels him to refuse offensive upgrades for his creation, the Aphrodite A, despite repeated requests from his daughter, Sayaka Yumi, who pilots it. During crises, his leadership involves analyzing mechanical beasts' weaknesses and advising pilots like Koji Kabuto, though he struggles to curb Koji's impulsiveness. Facing imminent laboratory destruction, he demonstrates a willingness to sacrifice himself rather than surrender or evacuate, reflecting a deep sense of responsibility.

His relationships are complex. As Sayaka's sole parent, he neglects her emotional needs due to work commitments, creating tension. He acts as a father figure to Juzo Kabuto's grandchildren, Koji and Shiro, showing patience toward Koji's recklessness but concern for his safety. His professional rapport with laboratory staff is marked by mutual respect and collaboration.

Scientifically proficient in robotics and photon energy, Yumi developed the Aphrodite A based on Juzo Kabuto's notes and later created its successor, the Diana A. His expertise includes memorizing critical blueprints like the Jet Scrander and devising backup systems for Mazinger Z. During conflicts, he coordinates defenses, activating the laboratory's barrier against Baron Ashura's assaults or deploying the Pilder support vehicle for Koji.

In the *Mazinkaiser* OVA, his role intensifies as Dr. Hell's forces escalate attacks. He oversees the deployment of the Mazinkaiser, explaining its capabilities to Koji and advising during battles against adversaries like Gamia Q and DamDam L2. He attends high-stakes government meetings to advocate for the laboratory's role in countering Dr. Hell, though these efforts are interrupted by Ashura's ambushes. His leadership proves pivotal during the Ghost Mechanical Beasts invasion, where he evacuates staff and coordinates with allies like Boss Borot to ensure survival.

His background reveals limited personal details; his early life and the identity of Sayaka's mother remain unexplored. He worked under Juzo Kabuto as an apprentice, inheriting his mentor's vision for photon energy's peaceful use. In *Mazinger Z: Infinity*, he transitions from laboratory director to Japan's Prime Minister, with Sayaka assuming leadership of the Photon Power Laboratory.

His surname "Yumi" (弓) means "archery bow," while "Gennosuke" (弦之助) combines "string/bowstring," "this," and "help/rescue."