Hagakure Kakugo hails from a lineage dedicated to battling monstrous threats in post-apocalyptic Tokyo. Trained by his father Oboro alongside his sibling Harara, he acquired specialized combat skills and technological enhancements. His training encompassed mastery of the Zero Defense Form martial arts style and the use of eight steel balls embedded in his body; these balls can be absorbed to coat his skin in metal or ejected as weapons. His signature technique, Impact, redirects an opponent's attack energy back at them. He operates using the Fortified Armor Shell Zero, an exoskeleton forged from the souls of 3000 sacrificed Japanese soldiers by his grandfather, former Imperial Japanese Army scientist Shiro Hagakure. These souls form a collective consciousness manifesting as grimacing skulls that communicate with and advise Kakugo during battle. Unlike his sibling, Kakugo remains committed to protecting humanity despite the armor's dark origins. The spirits' support is unwavering, and he demonstrates empathy by self-mutilating to share their pain after learning their history. When Harara becomes corrupted by the evil within their sibling's armor Kasumi, Kakugo engages in a prolonged conflict to stop Harara's campaign of extermination. This culminates in a decisive battle where Kakugo defeats Harara, leaving his sibling comatose. Kakugo's resolve is tested through numerous encounters with Harara's lieutenants, the Tactical Fiends or Evils, including monsters like Hamuko, Dogumakuro, and Chidokuro. These conflicts often require strategic use of his abilities and armor. During them, he confronts allies transformed into threats, such as Tsumiko Horie, whom he rescues from mutation. In later media, Kakugo reappears in the sequel *Exoskull Zero*, awakening from a long slumber to encounter other armored warriors with divergent approaches to justice, expanding the setting into renewed chaos while his core mission persists. The pseudo-prequel *Efu no Shichinen* further explores his legacy in an Edo-era context, connecting to broader thematic elements of his family's technology and conflicts. His physical appearance typically includes glasses, a white naval-style uniform, and short black hair. Personality-wise, he is characterized by sternness, compassion, and an unwavering sense of duty, often prioritizing civilian protection over personal safety. His interactions reflect a disciplined yet empathetic approach, including moments where he mourns fallen innocents like Kazu Shimada.