Blood-C: The Last Dark continues the story of Saya Kisaragi in a world where Earth is inhabited by terrifying monsters called Elder Bairns. To keep humans safe, these creatures observe a covenant known as Shrovetide, a fragile balance that lets Elder Bairns feed for a limited time while humans try to endure. The first film in this arc showed Saya fighting the intruders that threaten her village, but the truth about her own nature runs deeper: she is an Elder Bairn herself, bound by an oath that forbids her from drinking human blood. That oath becomes the focal point of a cruel wager she makes with Fumito Nanahara Fumito Nanahara, the head of the organization that oversees Shrovetide. The stakes are high, and the wager goes disastrously wrong, ending in a massacre that leaves only Fumito, his ally Yūka Amino, and Saya standing. Betrayed by the very person she hoped would protect her, Saya vows vengeance against Fumito and begins a new, darker chapter of her life.
Six months pass, and Tokyo has grown tense under the shadow of Fumito’s machinations. A new threat emerges when Saya rescues a girl named Mana Hīragi from a rampaging Elder Bairn. Mana’s rescue pulls her into the orbit of SIRRUT, a covert resistance group fighting against Fumito’s control. SIRRUT is led by Kuroto Mogari, a relative of Fumito, whose family was slaughtered so Fumito could bend Tower and its offspring corporations to his will. Kuroto offers his aid to Saya in exchange for her cooperation, and after being pursued by Tower’s agents and after Saya helps fend off enforcers who try to clamp down on Tokyo’s youth, she agrees to work with the resistance. As the new alliance forms, Mana’s backstory begins to unfold: her father disappeared after assisting in research around Tower, hinting at deeper secrets behind the power struggle.
To move the fight forward, Mana’s technical prowess becomes essential. Recovered memories and sharpened hacking skills allow her to locate Tower’s main base, where Saya infiltrates a building controlled by Fumito. The mission escalates quickly as they confront Tower’s security chief, Kutō, who uses Saya’s own blood to morph into an Elder Bairn hybrid. The true purpose of the base becomes clear when Saya finally faces Fumito in the building’s basement and encounters Kuroto again, only to be drugged by a mysterious substance administered by Kuroto. The revelations flash rapidly: Fumito and Kuroto had been colluding, each killing the other’s family to consolidate power over Tower and its network, Seventh Heaven. The motive behind much of the violence becomes even more personal when Saya learns that the Elder Bairn who attacked Mana was actually Mana’s father, a revelation that shakes the foundation of Mana’s trust in her own history.
The confrontation crescendos as Kuroto attempts to finish Mana’s father to secure Shrovetide control, but Fumito intervenes in a brutal twist, stabbing Kuroto with a vial of Saya’s blood. The transformation of Kuroto into an Elder Bairn seed seals his fate, and the moment marks a turning point in the conflict. Fumito’s plan, revealed in full, is to dissolve Shrovetide altogether because the balance between humans and Elder Bairns has shifted as the apparent Elder Bairn population dwindles. He then fuses with the seed, growing into a colossal Elder Bairn that Saya must defeat. In the aftermath, Fumito confesses that his goal was not only to control the balance of power but also to draw closer to Saya and free her from the oath that binds her. Yet even as he accepts his loss in the wager, he chooses a final, self-inflicted death by impaling himself on Saya’s sword.
The dust settles with a quiet, uneasy peace. Saya does not return to SIRRUT; she vanishes, leaving the city to its fragile, restored balance. In the political wake, Yūka Amino ascends to Tokyo’s governorship and repeals the Youth Ordinance Bill, signaling a rollback of the strict controls that once shadowed young people online and in public life. SIRRUT disbands back into ordinary life, and Mana, holding onto the memory of the strange, dangerous path she walked, begins a quiet search for Saya, her presence briefly appearing again on the streets of Tokyo, a reminder that their fates remain intertwined even as the city tries to move forward.
