Voiced by: Eri Kitamura (Japanese), Kari Wahlgren (English)
Age 173 (appearance age 16): At the start of the series, Saya appears to be a high school girl   more...living a normal life on the Japanese island of Okinawa. She is adopted and has no memory of her earlier than one year ago. She is able to heal all her injuries very quickly but must regularly receive blood transfusions or drink blood to remain healthy.

Despite these strange traits, she has the outward appearance of a young human teenage girl with an unusually large appetite (used as a humorous effect several times), most likely a side effect of her inhuman metabolism. However, she does start having more flashbacks of her experiences fighting Chiroptera in the Vietnam War and in 1920's Russia. Her oldest memories are from her birthplace at Joel's mansion called the Zoo in 19th century France. 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. She also can spend decades hibernating in a cocoon, only awaking for a few years before sleeping again. Whenever her and Diva's blood mix, the blood crystallizes and disintegrates. She is a skilled athlete and her weapon of choice is a nihonto (Japanese sword or katana, though one slightly changed to have features analogous to those of a kopesh) with bohi or grooves specially designed to spread her blood through its entire blade, making it a deadly weapon both for Diva and any Chiroptera made from Diva's blood. The first blade in the series is broken by Amshel, 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 blood which crystallized when she killed him with her own blood in order to spare him the fate of fully becoming a Chiropteran.
Saya's human personality is usually that of a cheerful and optimistic girl but her suppressed vampire side (evidenced whenever her eyes turn red in contrast to her twin sister Diva's blue eyes) is infinitely more cold, calculating, and with a warrior's edge that brooks no foolishness. However, as of late 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. It is revealed that after she and Haji had left the 'Zoo', she made him promise to kill her after Saya has slain Diva so as to prevent the survival of the Chiroptera. Post episode 33, Saya gains a much darker appearance and personality (there are several references that she has already lost hope in things - this might be attributable to Riku's death), sporting a dark maroon trenchcoat 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 somewhat marked change in Saya's normally cheerful personality is also accompanied by an acceptance of her Chiropteran biology, with a willingness (of necessity) to feed off of Haji's blood with little shame.
Saya confronted her sister in the Metropoilitan Opera House, and the duel ended with the sisters piercing their swords through each other. Though Diva began crystallizing, Saya survived as Diva's blood lost her potency due to her having children. At Kai's pleas, Saya made a decision to live instead of die and to also let Diva's twins live. Shortly after her return to Okinawa, she went into her hibernation period, and Kai along with the twins watches over her as she rests in the Miyagusuku family grave. Haji also visited, leaving his hair ribbon tied around a rose.  less

Voiced by: Katsuyuki Konishi (Japanese), Crispin Freeman (English)
Age 142 (appearance age 20): He is partly instrumental in Saya's "awakening" and his   more...right arm is covered in bandages, hiding some Chiropteran features. Haji first met Saya when he was a child and was bought by Joel to be her companion and hopefully mate and create more specimens someday. He lived with her in Joel's mansion for many years. But one day he fell from a cliff in an attempt to pick a flower that Saya wanted as a present for Joel's birthday. Seeing him bleeding everywhere and not really understanding that people don't drink blood to remain healthy, Saya gave him her own blood. Thus she unwittingly turned him into her "Chevalier."

Since then, Haji's single wish is to protect Saya and fulfill her wishes. It is also revealed that unlike Saya who "created" him, Haji neither eats, sleeps, nor go into long periods of hibernation. But in volume 2 of the manga , there is a scene in Vietnam where he was shown to be eating noodles with Kai, though given the situation then, this was done probably for comical effects. Saya was the one who taught Haji to play the cello when he was young, but it didn't take long for him to surpass her. He is often seen with a 'cello case in which he hides Saya's sword, but he also uses the case as shield or even as a blunt weapon; it seems to be virtually invincible, easily deflecting blows from things that can punch through walls.
Much like how Saya looks eternally young, Haji appears to be in his early twenties even though he has been around since the 19th century. It was implied in episode 28 that for some reason he doesn't believe he will be around forever. This may have something to do with his promise to Saya to end her life for her. Until recently he sealed his Chiropteran powers because of an incident where he killed many people who wanted to capture Saya, upsetting her. As of episode 43, he has revealed he is capable of flight via a pair of bat-like wings. In the final episode, he kills Amshel with Saya's sword in conjunction with a large chunk of a balcony collapsing on the two. Shortly before that, he confessed that he loved Saya. He survives and the last thing seen of him is the rose he leaves at the Miyagusuku grave where Saya sleeps  less

Voiced by: Hochu Ohtsuka (Japanese), Wally Wingert (English)
Age 59 (2005): An Okinawan-American US Army veteran, George served in the Vietnam War and   more...now lives on Okinawa with his adopted children Saya, Kai, and Riku. He lost his wife and biological children in an accident years before. Later in the series, after becoming a Chiropteran himself, he asks Saya to kill him by pouring her blood on his wounds, something she does reluctantly only out of love and compassion for the man she knew as her father.  less