Kaito is a vampire hunter and a teacher in training at Cross Academy. Under certain circumstances he trained to be a vampire hunter with Zero and Ichiru Kiriyuu under Yagari's teaching for a while. Kaito and Zero became good friends in the time they were together traing with Yagari.
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Whilst training with the Kiriyuu twins, he bullied and held a strong hate for Ichiru for him simply being weak and holding himself and Zero back. Kaito had an older brother, who was also a vampire hunter and never hung around with Kaito. His brother went missing on a mission. Kaito and Zero were sent on a mission to kill a vampire who had turn into a level E, but the vampire turned out to be Kaito's brother. After finding out the truth about his brother, Kaito then kills him. 
