Absolute Anime

Arcueid Brunestud, for most of her existence, was the princess of the Shinso, or "True Ancestors", a race of vampires that were more closely associated with nature spirits. Unlike the classic vampires, Shinso do not require blood to exist, and can live in the daylight. Arcueid, in fact, hates the taste of blood, and her reign was nothing spectacular, but she lived uncorrupted by the world... that is until a mage of the Shinso, Roa, tricked her into drinking blood hidden in a white rose.

Since her fall from grace, Arcueid spent the better part of 800 years hunting down Roa... and the "Dead Apostles" that Roa had created from drinking their blood. At the same time, Arcueid was fighting her own thirst for blood while fighting Roa and his various incarnations, which included Ciel. Every time she beat Roa back, Arcueid would go into hibernation, waiting for the time Roa would strike again.

But in her latest battle, Arcueid ran into a complication. By chance, she had ran into Shiki Tohno... and out of compulsion, Shiki had killed Arcueid, cutting her body into seventeen pieces. Arcueid, however, was able to heal herself, although not completely and now is weakened. She then enlisted Shiki to aid her in fighting Roa, which would allow her to try to recover... and fight the growing bloodlust within her.

The woman calling herself Arcueid Brunestud is really the immortal princess of the Shinso ("True Ancestor"), a clan of vampires who are essentially like spirits of the natural world. She came to deal with the threat of the Death Apostle, those whose blood was drunk by the Shinso and are like stereotypical vampires. She is aided by Shiki Tohno, who can cut the lines he sees on objects and people, causing their destruction.