Kaien Cross

Headmaster Kaien Cross (黒主理事長, Kurosu Kaien Rijicho) is a character in the manga and anime series, Vampire Knight by Matsuri Hino. In the story, he is both Headmaster of Cross Academy, and current head of the Vampire Hunters Association. He is also known as the strongest vampire hunter in history, and is quite the legend. He is the guardian of Zero Kiryu and adoptive father of Yuki Cross, the heroine of the story. In the first and second arcs, Kaien's role in the story is largely observant, and he takes little action until the hunter's association attacks the Night Class at the end of the second arc. After this point in the series, Kaien takes on a more direct role in the action.

Appearance
Kaien has long straw coloured hair and usually pulls it back into a ponytail. Though he is over 200 years old, he looks to be in his mid twenties. Kaien enjoys wearing very odd clothing and can be spotted with oversized lion feet slippers and large colourful hats. Kaien is one of the few characters that wears spectacles, though he removes them in times of action.

Personality
Kaien sports a cheerful personality, yet can be serious at the same time. It can be said that he has a few odd personality quirks, such as his propensity to launch into tearful dramatics over the idea of being a poor parent to Yuki. Additionally, he enjoys ribbing his adopted children, particularly Zero, who refuses to consider Kaien and Yuki family, a fact which Kaien jokingly claims breaks his heart. Kaien also enjoys cooking very strange food and making Yuki and Zero try it. He is often mockingly sad if they don't enjoy it.

Kaien can also appear thoughtless, frequently overriding and ignoring Zero's distaste for vampires. He often tells only half truths to protect Zero and Yuki, and kept his knowledge of Yuki's past secret from both her and Zero. He is however quite proud, and very protective, of both his children.

Background
Kaien has not always been so happy go-lucky. At his prime as a Vampire Hunter, Kaien Cross was known as the "Vampire without Fangs" due to his strength and skill as a Vampire Hunter, and also the fact that he was born with an abnormally high amount of vampire genetic material compared to other Vampire Hunters. Thanks to his vampire DNA, Kaien is over 200 years old and no longer seems to age.

Kaien is friends with pureblood vampire, Isaya Shouto, and used to intentionally pick fights with him. After befrending Juri and Haruka Kuran, Kaien took on Juri's dream of establishing a school for vampires and humans, and retired as a Vampire Hunter in order to establish Cross Academy 16 years prior to the story's beginning. Following the deaths of Juri and Haruka, Kaien took in their hidden daughter, Yuki, after Kaname Kuran brought her to him for safekeeping. Thus Kaien became Yuki's very doting and slightly odd father, much to Yuki's annoyance. Kaien also took in Zero Kiryu several years later, after the deaths of Zero's parents. Like Yuki, Kaien also wished to adopt Zero, but Zero refused.

Shortly after Zero's arrival, Kaien, with Kaname's assistance, is finally able to establish the Night Class to promote understanding between humans and vampires. Due to the vampire presence at the school, Zero initially refuses to attend high school and is left behind a year, but Kaien is later able to convince him to attend the following year in order to prevent Yuki from being alone in the duties of being a guardian.

Plot Summary
At the beginning of the manga, Kaien is portrayed as the headmaster of Cross Academy and adopted father to Yuki and Zero. While he seems to be aware of what is going on at the school at all times, he leaves the enforcement of school discipline (particularly of maintaining the peace between the vampire and human students) to Yuki and Zero, who are Cross Academy's only school prefects, a fact which annoys Zero as he believes he needs more than Yuki's assistance in order to maintain order. After Zero completely awakens as a vampire, it is revealed that Kaien knew the truth behind the deaths of Zero's parents all along and that he had been the one to take Zero to get his tattoo in the hopes that it would slow down Zero's transformation into a vampire. Kaien also performs the ceremony to have Yuki tame Zero.

Later on, after Yuki's memories of the past begin to awaken, Kaien accompanies Yuki and Zero to the Hunter Association's main headquarters in order to look up the records on Yuki's history. While there, Yuki accidentally uncovers the fact that Kaien was once a Vampire Hunter, a fact which does not surprise Yuki; however, Kaien states he was ashamed for having killed vampires in the past and didn't want her to know. Yuki responds that he is her father and nothing has changed. Kaien is touched.

Once Yuki's memories finally return and she reawakens as a Pureblood vampire, Kaien admits, to a disgusted Zero, that he knew everything about her past but kept silent. When the school is subsequently attacked by Rido's legion of vampires, Kaien attempts to maintain order, but it is not until the Hunters arrive that he, along with Yagari, go out to defend the Night Class, declaring that while the Night Class is protecting the human students, he will protect the Night Class. During this battle, Kaien fights and kills the acting president of the Hunter Association, discovering in the process that the president had been slowly transforming into a vampire after drinking the blood of powerful vampires. After the battle ends, the Hunters take Kaien into custody in an effort to hold him accountable for failing to keep the school safe.

During the following year, Kaien has been in custody while Yagari acted as the chairman of the academy. Yagari and he convince Zero to return to school, albeit allowing Zero the use of one of his apartments. Kaien is now acting as the President of the Hunter Association, and returned back to the school as the Chairman. It is revealed that Yagari is actually the true head of the Hunters Association.

Kaien goes to Zero, who reveals to Zero that the Hunter Association intend for Zero to become their president in the future, and require him to attend the peace meeting. Kaien also tells Zero that he will stand between Yuki and Zero, if necessary, because he cares for both of them. Kaien attends the meeting with various other hunters. The meeting goes smoothly although Kaname interrupts the meeting to inform Kaien that he will be able to see Yuki at the party, to which Kaien thanks him. Kaien expresses doubts over the way Kaname dealt with the former Vampire Council, believing it to be too harsh, and at risk of alienating the other vampires, in particular the other Purebloods.

Kaien goes to see Yuki at the party, but expresses displeasure toward Kain over the difficulty in seeing her. His visit is delayed when they discover the body of a hunter. He gets to see Yuki when she walks into the room, but he finds it difficult to tell that a hunter was bitten by a Pureblood. After Ouri's death is considered an assisted suicide, Kaien declares that the Hunters can never let it happen again.

He is later seen in Isaya's house, just after Yuki's visit with him. When Isaya asks why Kaien didn't greet her before she left, he responds that it's fine since he didn't want her knowing that they were old friends, in case it influenced her way of seeing things. Kaien also remarks on how much Yuki has come to resemble her mother, but clarifies that he does not hold romantic feelings for Yuki at all. When Isaya comments that seeing Kaien as a father is something he never could have imagined, that he'd always thought Kaien would remain a neutral spectator just as he himself is, Kaien responds that by opening the school and caring for Yuki, he realized he could make a difference. He thinks that it is important that Yuki grew up watching that. Kaien then excuses himself to leave, telling Isaya that he had merely stopped by to greet him after waking up from a 50 year slumber, and to warn him about the trouble brewing in vampire society since the death of Ouri. Isaya wryly notes that Kaien's true message was "don't cause trouble" and states that Vampire Hunters are like the prefects of a school.

Juri Kuran
Kaien and Juri met as enemies when Kaien tried to kill her and they eventually became good friends.

Powers
Kaien is a very strong hunter, known as the best until he retired. Kaien is unusual amongst the vampire hunters, having stopped aging at 25 years old, they have been studying his DNA, which he is said to possess extremely high amounts of vampire DNA that stopped his aging and causes Zero to confuse him with that of a vampire's aura. Like all vampire hunters, Kaien is able to wield anti-vampire weapons and carries a sword hidden in a cane and he has an acute smell that senses vampires.

Trivia

 * Cross or Kurosu, means "black master." Kaien is a combination of kai, meaning "ashes", and en, meaning "village gate." The kanji for en is also used for Enma the ruler of the Underworld in Buddhist mythology.
 * Kaien often asks Yuki to refer to him as "father" when she calls him "Headmaster".
 * In the manga, when Zero was tamed, Kaien says something along the lines of "If you ever need to drink someone's blood, feel free to drink mine!". In the same panel, his chest reads "GAY".