Yuuki's adoptive parent, who also took Zero into his home several years ago. Headmaster Cross dreams of peace between humans and vampires, and established the Night Class to promote understanding between the two races. Although he is often eccentric, he has a serious side as well. It is revealed that he is a former vampire hunter.


In the latest chapters of the series, it is revealed that Cross Kaien was considered "History's Greatest Legendary Vampire Hunter" though he refused being called that way.