Saya Otonashi

In Blood: The Last Vampire
Saya (小夜) hunts Chiroptera using a katana. She works for a secret organization known as Red Shield. It is implied that she is the last remaining vampire, and in the movie, Saya is referred to as "the only remaining original". She has an evident disdain for humans, but says that she cannot kill them. Saya has no weakness to sunlight, although whether she has any of the other vulnerabilities commonly associated with vampires is virtually unknown. She does, however, become distressed when she encounters religious paraphernalia, including the uttering of "Jesus" early in the film, and the school nurse praying with a crucifix. Saya displays superhuman senses and strength, as well as cunning, resourcefulness, and skill. She is never shown to transform into a Chiropteran form. A manga series suggests she was a human-vampire hybrid. Her age is unknown, but a picture of her with nine other people is shown in the movie with the date 1892 and the word "vampire" attached to it. Though she holds most humans in disregard, she seems to have some sort of respect towards David. Also, after mortally maming a Chiropteran, she is seen kindly looking down at him and giving him her blood - appearantly to hasten his death.

In Blood+
Saya Otonashi (音無 小夜) in Blood+ is very different from the Saya of Blood: The Last Vampire. She was "born" in 1833 from a cocoon like object taken from a mummy of a Chiropteran along with another cocoon containing her sister Diva. Whenever her and Diva's blood mix, the blood crystallizes and disintegrates. She can only remain awake for a few years (three to four, at most) before sleeping again for three decades.

She is a skilled athlete and her weapon of choice is a nihontō (though one slightly changed to have features analogous to those of a kopesh) with an edge she can touch with her thumb while gripping it so as to draw blood, and bohi or grooves specially designed to spread her blood through its entire blade, making it a deadly weapon both against Diva and any Chiropteran made from Diva's blood.

Amshel breaks the first blade in the series, but she acquires a new sword from David with a red crystal at the base of its blade. This crystal is actually a piece of her adoptive father, George's body which crystallized when she killed him with her own blood in order to spare him the fate of fully becoming a Chiropteran.

First half
At the start of the series, Saya appears to be a high school girl living a normal life on the island of Okinawa. She is adopted by George Miyagusuku and has no memory of her life earlier than one year ago. She is able to heal all her injuries very quickly but must regularly receive blood transfusions to remain healthy. Despite these strange traits, she has the outward appearance of a young human teenage girl with an unusually large appetite.

Later on, she begins having flashbacks of her experiences fighting Chiropterans in the Vietnam War. Her oldest memories are from her birthplace at Joel's mansion called the "Zoo" in France during the 19th century.

Saya's human personality is usually that of a cheerful and optimistic girl, but her suppressed Chiropteran side (evidenced whenever her eyes turn red in contrast to her twin sister Diva's blue eyes and when her lips turn redder than usual) is colder, calculating, and with a warrior's edge, that brooks no foolishness.

However, as time progresses Saya has had very little to be cheerful or optimistic about as she learns more and more about herself and the enemies that stalk her. Her greatest fear is perhaps finding out that she is indeed the same or much worse than the very monsters she now hunts as hinted by the grisly yet splintered memories she has of her dark, shadowy past.

Second half
It is revealed that after she and Haji had left the "Zoo", she made him promise to kill her after she kills Diva to prevent the survival of Chiropterans. Post episode 34, Saya gains a much darker appearance and personality, sporting a dark maroon trench coat and generally longer hair.

Past this point in the series, her willingness to co-operate with the Red Shield and with her own family drops, as she wishes not to endanger them any further, believing that her fight with Diva is hers to fight alone. This also somehow marks a change in Saya's previously cheerful personality, accompanied by an acceptance of her Chiropteran biology and a willingness of necessity to feed off Haji's blood. Even Moses and Karman remarks that she might, just like them, have already lost hope. It might also be said that Saya's depression stems from the fact that she is aware of her next hibernation period drawing near (she becomes prone to sudden bouts of fainting spells and as Solomon observes, her regeneration ability has somewhat slowed down). But everyone on Saya's side does their part to try to "bring" her feelings back during Javier's birthday party; the subsequent fight against Karl and the Corpse Corps; before they depart for Christina Island; and finally, before they set off for the grand finale trip to New York - so to let her know that this fight is not for her to bear alone, and that she is never alone.

In truth, not all of Diva's chevaliers are trying to take her life. The fourth brother, Solomon Goldsmith, fell deeply in love with her. He was first introduced to her as a delightful young man at the ball in her Vietnam school, and danced his only dance with her. After the dance he apologized, telling her that he had only asked her as she was the only girl who wasn't staring at him. Solomon only discovered her true identity when he was dragged off by Van Argiano, to "look" at some results, when Saya's friend Min called out her name. Solomon was greatly disturbed by Amshel's decision to eliminate Saya, and against his brother's will, set out in hope to persuade her to join his side. He saved her life many times as well.

Saya confronts her sister at the Metropolitan Opera House, and the final duel ends when they simultaneously pierce their swords through each other. Although Diva begins to crystallize, Saya survives as Diva's blood lost her potency due to her having children. Though Saya has said that she lives only to cut down Diva, whom she had released over a century ago, now that the deed is done, all Saya feels is a sense of emptiness and remorse at her sister's body that has been turned to stone. Through Kai's pleas and Haji's admittance of love, Saya breaks her former promise to Haji that she would die after the death of Diva and decides to live instead, and spare the lives of Diva's newborn baby twins as well.

Shortly after her return to Okinawa, Saya goes into her 30 year hibernation period, and Kai along with Diva's children watch over her as she sleeps in the Miyagusuku family grave. Haji had also visited, leaving a fresh pink rose with a ribbon at the grave.