Misaki Sakimiya, heiress to Sakimiya Steel, witnessed her parents’ murder by a serial killer in a childhood trauma that fractured her psyche, leaving her obsessed with the allure of violence. Raised in an orphanage, she was molded into the assassin "Zaki the Killer Killer" by mentor Lisa Kuraki, honed to hunt criminals and avenge her parents—a mission she fulfilled by bludgeoning their killer with a steel pipe, demanding answers about his enjoyment of death. Cheerful and remorseless, she treated assassination as a twisted game, her childlike charm contrasting her sociopathy. Her signature schoolgirl uniform—sailor collar with red accents, thigh-high stockings, cobweb shawl, red glasses, and choker—became a macabre trademark. Death reshaped her: resurrected as Corpse God’s zombie subordinate, she gained regenerative strength and dulled senses, later evolving into a vampire larva with bat wings, venomous fangs, and paralytic saliva. Her turning point came after assassinating Polka Shinoyama, only to face his revival and her own accidental death by Corpse God’s hand. Reborn as his undead ally, she navigated newfound humanity—apologizing for Polka’s death, forging genuine bonds, and grappling with guilt. Enhanced vampiric abilities allowed bat-like flight and gliding, though her transformations often left her clothes shredded. Surviving yakuza ambushes like the "human knots" incident showcased her regeneration, while partnerships shifted from utilitarian ties with associates like Takumi "Kuruphon" to a fraught loyalty to Corpse God, whose power earned her respect. Lisa remained her shadowy handler, directing her role in supernatural conflicts. Once driven by vengeance and thrill, Misaki’s refined upbringing let her charm high society even as she wielded crowbars and nail guns with brutal efficiency. Her journey twisted from bloodstained revenge to fragile redemption, balancing feral instincts with flickers of empathy—a killer forever dancing between savagery and the ghost of the heiress she might have been.