Blood-C focuses on Saya Kisaragi, an outwardly normal teenage high school girl who serves as a shrine maiden to a country town; in reality, she is a skilled swordswoman charged by her father to defeat Elder Bairns, monsters who feed on human blood.

As her battles grow more desperate and more people she cares for fall victim to the Elder Bairns, Saya begins finding faults in her reality, and eventually uncovers a disturbing truth about herself, the town and her surviving friends.

Its bloody violence, a stylistic choice following the series' themes, resulted in censorship in Japan and eventual blacklisting in China.

But while living a normal school life by day, Saya and her father spend the night defending the village against Elder Bairns,[5][a] monsters who possess inanimate objects to stalk humans and feed on their blood.

They find that the library is a fake, then Kanako confronts Saya with the living Nono, Nene and Shinichirō before forcing her to drink Elder Bairn blood.

These included concept supervisor and co-writer Junichi Fujisaku, one of the original creators of the Blood franchise; and director Tsutomu Mizushima, whose most notable recent work was the anime adaptation of CLAMP's manga xxxHolic.

[5] The opening theme "Spiral" was performed by Dustz, who worked hard to make the song a suitable addition to the Blood canon and incorporated both Japanese and French lyrics.

The ending theme, "Junketsu Paradox", was sung by Nana Mizuki—the voice actress for Saya—who used the anime's story as inspiration and incorporated archaic phrases for the lyrics.

The only elements to be retained were the first name of the main character, having a katana as her weapon, and the basic premise of her defeating monsters with that sword.

[7] The wish for the project to be distinct from earlier entries was what spurred the collaboration with CLAMP, which became a large part of the anime's marketing campaign.

[17] Fujisaku, when asked in an interview to describe his one creative ambition for the series, said that it was to fully expand and build upon the basic concept established in Blood: The Last Vampire.

[19] When asked, Mizushima did not find the change from his previous comedy anime-based turnout a barrier to his work, but did feel pressure when handling a project within the Blood franchise.

Fujisaku pointedly avoided contributing too much to the dialogue as Ohkawa's writing had a very distinctive style, his alterations made only due to story inconsistencies.

The series broke from conventions of a hero-focused anime by portraying the relationships between Saya and those close to her in a very shallow way during the opening episodes.

For the final few episodes, when the truth is revealed about Saya and her school life, the supporting cast were generally portrayed as "hateful" people that the viewers would wish to see die.

[6] They were initially conceived by Ohkawa as Japanese versions of the Great Old Ones, figures from the Cthulhu Mythos created by H. P. Lovecraft, but this was changed.

While some elements remained from the initial concept, the final Elder Bairns' physical forms as faced by Saya were inspired by yokai from Japanese folklore at Mizushima's insistence—this design choice was decided upon after storyboarding finished for the fight against the first episode's Elder Bairn, which was modeled after a Jizo statue.

[15] The disguised form of the Elder Bairn from the fifth episode was based on train carriages from the Kamikōchi Line in Nagano Prefecture that Mizushima had enjoyed traveling on as a boy.

[26][32][33][34] During the original broadcast, scenes where Saya's friends or other humans characters were killed by the Elder Bairns—the process of which invariably involved extensive blood and gore—were censored with areas of light and darkness.

[15][35] During its original run, it was broadcast simultaneously in North America, the United Kingdom, Canada, Australia, New Zealand and South Africa through the Western branch of Niconico.

[41] Blood-C was one of three anime cited—alongside Highschool of the Dead and Terror in Resonance—in a warning given by the Chinese Ministry of Culture to video streaming sites due to the series high violence.

[42] Blood-C was later put on a blacklist by the Ministry of Culture alongside 37 other anime and manga series in 2015, prohibiting its physical and online distribution in mainland China.

[57][58][59] Several actors from the play reprised their perspective roles for the live-action movies, mainly Kanon Miyahara as Saya Kisaragi, and Keisuke Minami as Fumito Nanahara.

[66][67][68][69] A second spin-off manga series titled Blood-C: Demonic Moonlight began serialization in the debut issue of Newtype Ace in September 2011.

[74][75] During its opening week, the first DVD/Blu-ray volume failed to reach a high position in the charts against many anime and live-action releases, selling only 727 copies according to Oricon.

[90] Richard Eisenbeis of Kotaku praised the character and Elder Bairn designs, and also enjoyed the questions the anime posed about where Blood-C fit in both the overall Blood franchise and the works of CLAMP.

He ended his review by calling Blood-C "a beautifully drawn show with excellent action and a legitimately compelling mystery".

He greatly enjoyed the horror and action aspects, but felt that the character-driven segments in early episodes threatened to drag down the whole experience due to mundane content and poor characters.

Santos unreservedly praised the music's quality and recurring melodies despite calling the opening and ending themes "typical angst-ridden rock numbers".

He called the English dub "understated (but not emotionless)", finding that it reinforced the overall atmosphere and only suffered due to the original writing.