Shiho Kimizuki serves as a primary deuteragonist, first appearing within Shinoa Hīragi's squad of the Moon Demon Company, a specialized unit of the Japanese Imperial Demon Army. He stands as the tallest squad member, distinguished by short, unkempt pink hair, thin matching eyebrows, and reddish-brown eyes. He constantly wears black, thick-framed rectangular glasses and sports two piercings in his left ear. His school attire featured a grey gakuran jacket with a black and teal-trimmed collar, frequently left unbuttoned over a hoodie. His army uniform consists of a long-sleeved black coat with light green details, gold buttons, a brown Sam Browne belt, white gloves, a white web belt with a gold waist-plate, uniform trousers secured by two white belts around his right leg, and knee-high black boots. Kimizuki combines sharp intellect with an initially confrontational demeanor, particularly directed at figures like Yuichiro Hyakuya. Academically gifted, he earned perfect scores in Latin, English, and Japanese tests without overt studying, often sleeping during class. He applies practical skills in vehicle repair, driving, and cooking. Though aloof and standoffish early on—insisting on being addressed by his surname—he gradually integrates into the squad, guided by a pragmatic focus on solving immediate problems. Beneath a hardened exterior lies a gentler aspect, shown when covering Yuichiro with his jacket to prevent illness or weeping upon learning his sister was safe. His defining trait is unwavering devotion to his younger sister, Mirai Kimizuki, for whom he would betray allies. He inwardly yearns for an ordinary life and harbors loyalty to his squad, often suppressing emotions to maintain level-headedness in crises. His background is marked by tragedy. As children, he and Mirai endured experiments by the Hyakuya Sect for the "Seraph of the End" plan, leading to the global apocalyptic virus released on Christmas 2012. This virus infected Mirai, leaving her bedridden. Three years later, at age eleven, Kimizuki defended her from children urging him to abandon or euthanize her, fleeing with her despite scarce resources and vampire threats. By 2020, he enlisted in the Japanese Imperial Demon Army solely to access advanced medical care for Mirai, initially serving in Shibuya's Military Police before transferring to the Moon Demon Company. His recruitment included training under Guren Ichinose, who selected him for a black demon weapon contract. His story unfolds through critical arcs. During military training, his rivalry with Yuichiro peaked during a partnered aptitude test against cursed puppets, interrupted when Mirai's health deteriorated. Yuichiro's insistence on family loyalty compelled Kimizuki to visit her, shifting his perspective and fostering reluctant camaraderie. He later acquired twin black demon swords after enduring a mental battle with the demon Kiseki-o, who exploited his guilt over Mirai's condition. As part of Shinoa Squad, he participated in missions defending Shinjuku from vampire invasions and attacking nobles in Nagoya, demonstrating vital tactical acumen by taunting nobles to prevent reinforcements or using quick thinking during urban combat. A devastating turning point occurred when Mirai was transformed into a seraph and killed by Guren Ichinose. Shattered, Kimizuki deserted the army, declaring he would betray anyone to save her. He later aligned with Guren's plans upon learning their broader context, though resentment simmered during confrontations about withheld truths. His combat abilities evolved through his contract with Kiseki-o, manifesting powers such as summoning infinite coffins for containment or transportation, neutralizing demonic possessions like restraining Asuramaru within Yuichiro, and excelling in close-quarters combat with dual swords. Kiseki-o's abilities expanded to include coffin-based portals for teleportation and tracking desires through psychic insight, utilized during battles in interdimensional realms. Key relationships define his interactions: his protective bond with Mirai remains his core motivation; his rivalry with Yuichiro softens into mutual respect; his closeness to Yoichi Saotome emerges in shared vulnerability, urging Yoichi to shoot them both during a high-stakes sacrifice; and his dynamic with Mitsuba Sangū involves frequent verbal sparring underpinned by underlying trust. Even after Mirai's death, his commitment to Shinoa Squad endures, balancing personal anguish with squad loyalty.