Kai Miyagusuku

Kai Miyagusuku (宮城 カイ Miyagusuku Kai) is one of the main protagonists of the series. He is the adopted son of George Miyagusuku hence, Riku and Saya's "elder" brother.

Appearance
Kai is a tanned, athletic boy with brown eyes and average height. He has orange hair throughout season 1 & 2. After the year lapse from Riku's death, his hair is shown to have turned to brown and complexion a bit fairer (probably due to going out only at nighttime chiropteran hunting).

Life in Okinawa
Once a popular student at school and a star athlete, Kai quits playing baseball shortly before Saya's arrival and has been getting into more fights at school. His debut in the anime begins with him taking Saya on his bike to the hospital so she can take treatment (blood transfusions). Later he goes to find her at the school, because Saya forgot her track shoes. But there he sees her killing a chiropteran.

After George was attacked by Forest, Kai goes to get revenge but fails to fight the chiropteran and Saya finds him at the port and kills the Chiropteran that hurt her father. His father's death forces him to grow up and try his best keep his family united.

In Vietnam
He goes to Vietnam with Saya and Riku, but is left behind in a city in Vietnam while Saya goes to investigate in the all girls high school. There he meets Mui, a girl who becomes Riku's friend. He also gets kidnapped along with Riku and Mui and ends up in Karl's mansion in the jungle. He manages to set themselves free as Saya and the rescue party arrive. When Saya goes out of control, killing her own teammates and draining Hagi's blood, Kai shouts out to stop her. His call brings her back to senses and she regains control over her powers.

The Truth
Kai is given to read Joel's Diary and learns about Saya's true identity. At the zoo, when Diva drains Riku's blood, he requests Saya to heal his brother with her blood. But as she does so, Riku becomes Saya's chevalier. Kai struggles greatly over Saya, and later Riku, not being human anymore. As he finally comes to terms with both, Riku is raped and killed by Diva, and Saya disappears for a year.

After Riku's Death
After the destruction of the Red Shield and Riku's death, Kai lives with Lewis and David in an orphanage in London, actively hunting chiropterans with Lewis and honing his skills as a soldier in the war against Diva and her minions. With David drowning in alcohol and regret, Kai takes over many of his responsibilities in chiropteran-hunting. Following the tradition of Red Shield, Kai wears a diamond-shaped pendant with a crystal from Riku's remains crested in it. As the last surviving family member of Saya's adoptive family, he has sworn to protect her and return to Okinawa with her once everything has been settled.

When the Feud Ends
After Saya kills Diva, he is able to convince her to continue living, and prompts Hagi to "disobey" Saya and confess his own love for her. Saya and Kai return to Okinawa and reopen their late father's restaurant. A month later, Saya goes into her hibernation cycle and Kai puts her in the family crypt to sleep. Per his promise to Saya, he raises Diva's daughters as though they were his own. Together, they regularly visit Saya's resting place to keep an eye on her while she sleeps.

Personality
In the beginning half, Kai is shown to be quite immature. He jumps to actions without thinking and fights out to subdue his inner conflicts. After George's death, he becomes the man of the family and tries to bind themselves together. However, he is over protective of both Saya and Riku. As he struggles within himself regarding Saya after knowing her true identity, Riku happens to step in his shoe. When Kai gets over the fact that Saya and Riku are different from him and manages to believe that they can still be a family, Riku dies in Diva's hands.

Riku's death changes Kai. He faces his responsibilities, hones his skills to be ready, bears the torch of Red Shield to keep hope alive. He believes that Saya will come and his faith pays off.

Skills
Athletics: Kai was one of the most popular star athletes in his school excelling in baseball.

Marksmanship: Initially Kai has little skill in marksmanship, but he improves as the series goes on.



Weapon
When George is kidnapped, Kai steals his father's M1911 pistol to try to rescue him. David confiscates it, but later returns it to show that he feels Kai had matured enough to handle it. After Red Shield's HQ is destroyed, Kai hones his marksmanship skills, practising with the pistol in the store at Glay's farmhouse. Kai uses it as his primary weapon for the remainder of the series.