The current top ranked vampire hunter, Toga Yagari, formerly trained Zero to be a vampire hunter. He had lost his right eye due to trying to save Zero long ago from a level E vampire. He showed up once at Cross Academy serving for a short while as a Night Class teacher to decide whether Zero is considered dangerous or not. He also appears briefly in volume five, when he appears shocked about the council's decision to punish Zero.
Yagari reviled that the level E that he killed to save Zero and that cost him his right eyes was actually his fiancee.