TV-Series
Description
Keisuke Sannan serves as a vice-commander of the Shinsengumi, alongside Toshizo Hijikata under Commander Isami Kondou. An intellectual often seen wearing glasses and engaged in strategy, Sannan presents a polite and amiable exterior, though his words carry subtle sharpness. He values his comrades and the Shinsengumi deeply, yet possesses a cynical streak some interpret as a "black heart."
A severe injury to his left arm during an Osaka skirmish renders him unable to wield a sword, shattering his samurai identity. This fuels profound bitterness and self-loathing. He grows irritable, isolates himself, and perceives concern, like Chizuru Yukimura's attempts to help, as pity, deepening his resentment. His interactions turn passive-aggressive, causing many members to avoid him.
Desperate to regain his usefulness, Sannan secretly researches the Ochimizu, an elixir created by Chizuru's father that transforms humans into Rasetsu—beings with enhanced strength and regeneration, but vulnerable to bloodlust. Consuming it heals his arm but transforms him into a silver-haired, red-eyed Rasetsu. His focus shifts to leading the Rasetsu Corps and relentlessly experimenting to control the elixir's side effects. This obsession strains relationships, particularly with Hijikata, who suspects Sannan's methods grow ruthless.
In *Record of the Jade Blood* (Season 2), Sannan's actions escalate. He temporarily allies with Kodo Yukimura to advance his research, appearing to betray the Shinsengumi. Establishing a base at Sendai Castle, he gathers Rasetsu as weapons against the Imperial Army. This is later revealed as a ruse to infiltrate Kodo's operations. Confronted by Hijikata and Heisuke Toudou, Sannan turns against Kodo, declaring loyalty to the Shinsengumi. He justifies his actions as necessary to save other Rasetsu from their grim fate, acknowledging prolonged Ochimizu use drastically shortens lifespans. During the ensuing battle, his body succumbs to Rasetsu degeneration, and he disintegrates into ash.
In other story routes, his path diverges: in Heisuke's route, he descends into madness as the primary antagonist; in Hijikata's route, he maintains control over his Rasetsu traits but feigns obsession strategically; in Iba Hachiro's route, he permits Chizuru to search for her father's research before dying off-screen in Sendai.
The OVA *Tsukikage no Shou* depicts an alternate conclusion where Sannan survives and travels to Europe with Chizuru. They seek a cure for the Rasetsu condition, investigating parallels between Ochimizu and European vampire lore. Learning of Japan's impending sword ban, he expresses no regret, valuing his ability to support Chizuru.
In the spin-off *Hakuouki SSL*, a modern reimagining, Sannan appears as a school nurse, free from his historical injury and Rasetsu transformation. He retains his intellectual, reserved nature but exhibits a gentler, more approachable personality. He forms a bond with Chizuru, displaying kindness and occasional shyness, contrasting his main series portrayal.
A severe injury to his left arm during an Osaka skirmish renders him unable to wield a sword, shattering his samurai identity. This fuels profound bitterness and self-loathing. He grows irritable, isolates himself, and perceives concern, like Chizuru Yukimura's attempts to help, as pity, deepening his resentment. His interactions turn passive-aggressive, causing many members to avoid him.
Desperate to regain his usefulness, Sannan secretly researches the Ochimizu, an elixir created by Chizuru's father that transforms humans into Rasetsu—beings with enhanced strength and regeneration, but vulnerable to bloodlust. Consuming it heals his arm but transforms him into a silver-haired, red-eyed Rasetsu. His focus shifts to leading the Rasetsu Corps and relentlessly experimenting to control the elixir's side effects. This obsession strains relationships, particularly with Hijikata, who suspects Sannan's methods grow ruthless.
In *Record of the Jade Blood* (Season 2), Sannan's actions escalate. He temporarily allies with Kodo Yukimura to advance his research, appearing to betray the Shinsengumi. Establishing a base at Sendai Castle, he gathers Rasetsu as weapons against the Imperial Army. This is later revealed as a ruse to infiltrate Kodo's operations. Confronted by Hijikata and Heisuke Toudou, Sannan turns against Kodo, declaring loyalty to the Shinsengumi. He justifies his actions as necessary to save other Rasetsu from their grim fate, acknowledging prolonged Ochimizu use drastically shortens lifespans. During the ensuing battle, his body succumbs to Rasetsu degeneration, and he disintegrates into ash.
In other story routes, his path diverges: in Heisuke's route, he descends into madness as the primary antagonist; in Hijikata's route, he maintains control over his Rasetsu traits but feigns obsession strategically; in Iba Hachiro's route, he permits Chizuru to search for her father's research before dying off-screen in Sendai.
The OVA *Tsukikage no Shou* depicts an alternate conclusion where Sannan survives and travels to Europe with Chizuru. They seek a cure for the Rasetsu condition, investigating parallels between Ochimizu and European vampire lore. Learning of Japan's impending sword ban, he expresses no regret, valuing his ability to support Chizuru.
In the spin-off *Hakuouki SSL*, a modern reimagining, Sannan appears as a school nurse, free from his historical injury and Rasetsu transformation. He retains his intellectual, reserved nature but exhibits a gentler, more approachable personality. He forms a bond with Chizuru, displaying kindness and occasional shyness, contrasting his main series portrayal.