Blood +

Blood+ (BLOOD+ (ブラッドプラス) ,Buraddo Purasu?, pronounced "Blood Plus") is an anime series produced by Production I.G and Aniplex and directed by Junichi Fujisaku. The series premiered in Japan on Sony's anime satellite channel, Animax, as well as on terrestrial networks such as MBS, TBS, and RKB on October 8, 2005. The final episode aired on September 23, 2006. Blood+ is licensed for international distribution in several regions through Sony Picture's international arm, Sony Pictures Television International (SPTI).
Blood+ was inspired by the 2000 anime film Blood: The Last Vampire; however, there are only a few allusions and basic elements from the film. Fujisaku has been involved with both works, including acting as the director for Blood+ and writing the novelization of Blood: The Last Vampire.
Plot
Under the care of her adoptive family, Saya Otonashi has been living the life of an anemic and amnesiac, but otherwise ordinary schoolgirl. Saya’s happy life is shattered when she is attacked by a chiropteran, learning that she is the only one who can defeat them.
Armed with her katana, Saya embarks on a journey with her family, allies, and her chevalier, Hagi, to rid the world of chiropteran and rediscover her identity. The course of the journey reveals the background history of the chiropterans and Saya's very deep past, which extends into the mid-19th century.
The series is initially set in present day (September 2005) Okinawa City (Koza), on Okinawa Island, near the US Kadena Air Base. In the course of the series, Saya visits locations across the world, fighting enemy chiropteran and searching for her origins.

[edit] Characters
Main article: List of Blood+ characters
Saya Otonashi, the central character, is a seemingly ordinary teenage girl adopted and living with amnesia. As her memories return, her life is turned upside down. She was born in 1833, survives on the blood of others, and is destined to destroy chiropterans and her twin sister Diva. Aiding her in her quest are her adopted brothers Kai and Riku and her ever-faithful chevalier Hagi. She also is aided by David, her protector from the powerful organization Red Shield.
Diva also has her own helpers, starting with her five powerful chevaliers: Amshel, Solomon, Karl, James and Nathan. They also have their own human allies as part of the Cinq Flèches Group that they operate, including Van Argiano who helps them develop the Delta 67 substance that Cinq Flèches uses to create chiropteran.
Working against both sides are the Schiff, a group of escaped artificial chiropteran created by Diva's group. The Schiff attack both groups, believing that the blood of Saya, Diva, or one of their chevaliers will save them from a fatal and painful disease they call the Thorn.