ข้อมูลอนิเมะBLOOD-C

Saya begins her morning meditating on a light that continues to escape her grasp. Her trance is broken by her father reminding her to hurry up if she wants to eat breakfast before school. At school she converses with her friends before having to head home early to their disappointment. At home her father hands her a katana and tells her to slay the Elder Bairn.

Saya keeps spending her days happily at school while hiding her duties as a hunter of Furukimono from her classmates. Itsuki Tomofusa, the class president, does his best to have Saya respond to his feelings without success, while she shows concern for Shinichirō Tokizane, another classmate who rarely speaks to her, but usually watches her from afar.

Saya learns that the bakery owner is missing and soon finds that a Furukimono is behind his disappearance. She fails to save his life, but manages to slay the creature, who speaks to Saya about a "Covenant" before passing away.

Saya asks Tadayoshi about the meaning behind the covenant mentioned by the Furukimono, but is dissuaded by him. That night, when confronting three Furukimonos attacking a group of workers, one of the mentions that the covenant between humans and Furukimonos must be honored.

Saya starts to have headaches related to visions, which eventually tire her. Her father sends her on a mission to kill a powerful Furukimono, but Saya prevails wondering about the Covenant the monster told her about. Back at her class, Saya and her class is told a story regarding the Furukimono and Humans, which eventually cause Saya to faint. The next day Saya is visited by Nene in the shrine but are attacked by another Furukimono.

Saya quickly searches for her sword but does not save Nene in time. After taking a day off to rest, Saya returns the next day only to find that Nono has also been absent from school. Kanako informs them that the school is closing down due to recent incidents. Saya is interrupted on her way home by a dog that is able to converse with her. Soon after, Nono appears and confronts Saya about Nene's whereabouts. A Furukimono forms from Nono's shadows and attacks the civilians. Saya kills the Furukimono but is unable to save Nono as she is killed in the process.

As Saya laments not being able to save Nene and Nono, she has trouble remembering who she made a promise to protect everyone to. She later encounters the dog from before, who is revealed to be Kimihiro Watanuki (From xxxHolic) in disguise, approaching her in order to grant a certain wish. The next day, as Tadayoshi tells her to keep her katana on her at all times, she arrives at school to find it empty besides Kanako. On the way back, Saya encounters a samurai-like Furukimono who casts doubt in her mind over whether to trust what Tadayoshi had told her. As Saya manages to regain her resolve and kill the Furukimono, who tells her to ask Tadoyoshi who she really is with his last breath, she is discovered by Shinichirō.

Shinichirō gets Saya to tell her about the Furukimonos, offering to be her confidant. As Saya returns home, she finds Tadoyoshi collapsed on the floor, though he passes it off as a dizzy spell. As the dog talks to Saya, asking her what would happen if she broke the promise she made, she experiences another headache as she recalls something concerning a reward and a punishment. After a few days of no Furukimono activity, Saya returns to school, where a Furukimono appears and attacks the class, killing several students. With no escape available, Saya is forced unsheath her katana in front of her friends to fight the Furkimono.

Saya struggles to keep the Furukimono from killing more students as she becomes tormented with flashbacks. Although she eventually manages to kill the Furukimono, all of her classmates besides Itsuki had been killed. After lamenting to the dog, who poses more questions about her nature, and being visited by Shinichirō, Saya comes to the realisation that only her class had been called to school that day. As Shinichirō's attempt to confess to Saya is put off by the arrival of Tadayoshi, Saya questions why she doesn't know her mother's name.