Kaien Cross

Headmaster Kaien Cross (黒主理事長, Kurosu Kaien Rijich) is a character in the manga series Vampire Knight by Matsuri Hino. In the story, he is the founder and Headmaster of the Cross Academy. He is also the strongest legendary vampire hunter in history. He is the adopted father of Yuuki Cross, the heroine of the story.

Background
Kaien was once friends with Juuri Kuran in his youth, but following an unknown incident they lost contact and Kaien turned into a cold blooded vampire hunter, Kaien was known as the fangless vampire due to his notoriety. He was strong enough to have been considered to lead the Vampire Hunters Association. At some point he came to the conclusion he needed to kill all the Kurans as the strongest of the vampire clans, during this time he stalked Juuri Kuran having not seen her for a longtime, but was defeated soundly by her. She bargained with Kaien to start a school where vampires and human could both attend.

With Juuri's influence, Kaien took on Juuri's dream and retired as a vampire hunter. Following the death of Juuri and Haruka Kuran, Kaien took in their hidden daughter, Yuuki Cross, after Kaname brought her to Cross for safekeeping. Cross kindly took Yuuki in, and became her very doting and slightly odd father, much to Yuuki's annoyance. Yuuki's adoptive father also took Zero into his home several years later. A few years following that, Kaien was finally able to establish the Night Class to promote understanding between humans and vampires.

Kaien sports a happy go lucky personality yet can be serious at the same times, it can be said he is a little strange but in reality, he's perfectly normal and a good adoptive father to Yuuki and Zero.