Gen Shiotsu, a former high-ranking Scepter 4 officer, rose to acting commander after Jin Habari’s death and Gōki Zenjō’s departure. His appearance adhered to the Blue Clan’s uniform code: a closed blue overcoat edged in black and gold, dark trousers, and knee-high boots reinforced with metallic detailing.

Strict and disciplined, Gen openly challenged leadership approaches, particularly opposing Jin Habari’s leniency toward Zenjō’s unpredictability. He advocated for unwavering obedience within Scepter 4, clashing with Habari’s preference for fluid teamwork over hierarchical rigidity. Beneath his austere exterior, Gen prioritized the welfare of Akito and Hayato Minato, overseeing their education and securing HOMRA’s aid to protect them during Scepter 4’s internal strife.

As leader, he partnered with the Gold Clan’s Strain Research Facility and Kōshi Mizuchi, which engaged in unethical practices—including torturing subjects like Anna Kushina to weaponize Strain abilities. After the facility’s collapse, Gen dissolved Scepter 4, permanently altering the organization’s trajectory.

Years later, he approached HOMRA’s Izumo Kusanagi to discuss the Minato brothers’ diverging career paths. Though taken aback by their choices, he expressed satisfaction at their independence from Scepter 4’s legacy. His dynamic with the brothers revealed a duality of unwavering duty and subtle paternal care, shaped by loyalties, obligations, and the ethical ambiguities of his command.