Hagi

Hagi (ハジ Haji) is Saya's first, and only living chevalier.

Appearance
Although Hagi is over 140 years old, he maintains the look of a 25 year old young man. It is the same age when time stopped for him, in other words, he became a chevalier. He has jet black hair falling down his shoulders. He usually keeps his hair tied up with a blue ribbon. In past flashbacks, he is shown to have let his hair loose. He is quite tall and has fair skin.

Attire
Past or present, Hagi always puts on Victorian style attire. In the Russian village, he was shown nude with a towel covering the lower half of his body. But Saya tells him off for showing up in such a way in front of two girls.

Meeting Saya
In 1870, Hagi was purchased by Joel and Amshel from his parents for a loaf of bread to be a companion for Saya, with hopes that they might mate and create more specimens for future experimentation. Hagi meets Saya who was apparently a spoiled child. Although ordered to follow her each and every orders constantly, he showed stubbornness at first. But when Saya listens to Hagi's story, she shows sympathy and reveals her friendly side. Hagi clings to this and their relationship develops.

Life in the Zoo
Hagi lives with Saya in Joel's mansion for many years, him growing up but her never aging. By this time, he and Saya have become quite close. He asks Joel about Saya and why she never grows. Joel reveals that Saya is special because of her blood.

Becoming Chevalier
In 1883, he falls from a cliff attempting to pick a flower that Saya wants as a present for Joel's birthday. Misunderstanding an earlier conversation between Hagi and Joel about why Saya lives on blood, and wanting to save him, Saya feeds him some of her blood, unwittingly turning him into a chevalier. Requiring blood to feed, Hagi transforms fully and kills many in front of Saya. The terrified face of Saya compelled him to take the oath of not transforming or taking blood.

Saya feels some guilt over this through the years, but when she apologizes, Hagi assures her that he has no regrets as it allows him to always be at her side while she lives her dream of traveling the world with her sword.

During Russian Revolution
In 1918, Hagi accompanies Saya to find Diva hiding as princess Anastesia. They scourge through Russia and end up in a village where they meet a girl named Sonia. She tries to get Saya alone but Hagi finds the truth about her. However, he is impaled with a tree trunk before reaching Saya. When Sonia changes to Grigori to kill Saya, Hagi returns, his wounds having healed. Saya kills Grigori but they do not manage to catch Diva who flees with Amshel to enter her hibernation.

Vietnam War
During the War, Hagi stays with the Red Shield and Military forces along with Saya in her casket. His blood is taken to inject in Saya's body to awaken her to help fight chiropterans. However, the untimely awakening makes Saya lose control over herself and go berserk. Hagi tries to stop her but she doesn't recognize him or his call. Rather she strikes at his arm with her katana, cutting it off. That part of his hand remains in chiropteran form and Hagi has kept it bandaged ever since. After that incident, Hagi keeps away from any of the shield members or militaries until Saya awakens once more.

In Okinawa
Hagi finds Saya in Okinawa but without her memories from past. He makes her drink his blood, forcefully attempting a mouth-to-mouth infusion. It awakens Saya and she kills the chiropteran in front. Later he properly introduces himself as her chevalier and gives her the katana he has been carrying after the Vietnam incident. He never tells what relationship he had with her in the past and lets her recollect memories herself. Gradually, she has flashbacks helping her regain her memories.

Journey with Saya
George's death brings about Saya, Kai, Riku and Hagi travelling together with the Red Shield to hunt Diva. Along most of the journey, Hagi stays silent, only staying by Saya's side to aid her in battle. An intimacy develops between him and Riku while he is constantly approached by the opposite from Kai.

After Riku's Death
Hagi spends a lot of time with Riku after he turns into a chevalier too. He teaches him to play the cello and tells him he could be there for Saya and play important role as chevalier. His days as a mentor were short as Diva cut short Riku's life. After Riku's death, Hagi follows Saya into wandering off pack and fighting chiropterans.

After the Duel Ends
After Diva's death, Hagi is about to fulfill his promise to Saya but gets smacked to senses by Kai. He then convinces Saya to live, confessing that he has always loved her. Agreeing that she does wish to live, Saya kisses him. As they, along with Kai and the rest of the Red Shield operatives, try to escape the opera house, Amshel attacks them, ripping off one of Hagi's arms. Saya reloads her sword with blood and is ready to fight him to protect Diva's babies. However, Hagi takes her sword and pushes her aside so she can escape while he impales Amshel himself. As Amshel crystallizes, he stabs Hagi through the chest and the ceiling collapses on them both. He tells Saya that he'll always love her. Saya screams his name before they leave. She believes he may be dead, but Kai reassures her that Hagi will return.

Watching Over
Sometime after Saya goes into her hibernation, Kai brings Diva's daughters to visit the Miyagusuku crypt where Saya is sleeping. When they arrive, they find a fresh pink rose with Hagi's blue hair ribbon tied to it. Hagi is alive and he is watching from afar, waiting patiently for his love to awaken after her thirty year sleep.

Personality
Hagi is shown to be quite serious. Later it is revealed that he actually gave up showing his emotions as a reason for being disappointed after the Vietnam incident. He felt as Saya's chevalier, he must only obey her orders and look after her well-being; not show his feelings for her.

Skills
Hagi plays the cello, a skill he learned from Saya and later surpassed his teacher. He usually carries his cello in a large black case.

Special Abilities
Feeding: As with most chevaliers, Hagi doesn't need to eat or sleep, and he stays awake while Saya eats, sleeps, or goes into long periods of hibernation.

Blood Attributes: 
 * Regeneration: Hagi's blood is capable of healing self wounds. Hagi_hand.PNGer, if the wound is inflicted by the queen who has made him chevalier, the regenerated part is likely to take permanent chiropteran form.
 * Awakening/ Strengthening Queen: Saya was forcefully awakened during the Vietnam war by injecting Hagi's blood. This indicates that Hagi's blood is a source of his queen's chiropteran strength. It can awaken her chiropteran mode. Saya is shown to consume Hagi's blood several times.

Transformation: Unlike Diva's chevaliers, Hagi never makes a full transformation into a chiropteran form; however, this is by his own choice rather than a limitation of his power. He only fully transformed to his chiropteran self when he first became chevalier. After seeing him kill people in that form, Saya got frightened and so he never fully transformed again. He keeps his right hand bandaged most of the time to hide the fact that its form is permanently chiropteran since Saya injured it while going crazy from being forced awake decades ago in Vietnam. In the opening credits of the final season, Hagi is shown with bat-like wings, but he does not use them in the series until Episode 43. One of his wings is torn by Amshel during the fight on top of the Chrysler Building.

Weapon
Hagi uses the cello-case as a blunt weapon and a shield, and the case also holds Saya's sword. He also fights with a handful of silver daggers that he keeps with him.