Blood+

Amnesiac high-schooler Saya Otonashi discovers she is a powerful fighter against bloodthirsty chiropterans and is drawn into a worldwide conflict tied to her forgotten past and a dangerous twin.

Blood+ follows Saya Otonashi, a soft-spoken girl living with the Miyagusuku family on Okinawa who suffers from severe memory loss and a need for regular blood transfusions. When chiropterans—monstrous creatures that feed on humans—attack, Saya instinctively wields a special katana and enters a combat trance that leaves her exhausted. Her adoptive brothers Kai and Riku, along with the quiet, cello-playing companion Hagi, are pulled into the danger as the attacks escalate. A secretive group known as the Red Shield contacts the family and reveals that Saya has fought these creatures before. Concrete early events include school life interrupted by sudden battles, Saya’s first full awakening with the sword, and the family’s decision to leave Okinawa after a devastating assault on their home.

As the group travels, Saya gradually recovers fragments of a much longer life and learns she is bound to Hagi as his chevalier while hunting the source of the chiropteran plague. The trail leads through international cities, underground labs, and confrontations with other enhanced beings who serve a rival figure named Diva. Riku’s fate becomes entangled with the bloodline conflict, forcing Saya to confront what her power costs the people she loves. Kai shifts from reluctant protector to active participant in the Red Shield’s operations. Later arcs center on stopping Diva’s public emergence, the creation of new chiropterans, and Saya’s choice to end the cycle even if it means facing her twin directly. The story closes on the aftermath of that confrontation and the survivors’ attempt to rebuild ordinary lives.