The Kiryus (Zero and Ichiru's parents)

They are Zero and Ichiru's parents and are also Vampire Hunters.

Character concept
Neither their faces nor names have been revealed. In the light novels, they are merely referred to as "Zero's mother or father".

Appearance
The father has a striking resemblance to Zero and Ichiru in terms of, hair and skin and the mother has long blonde-brown hair tied in a low pony-tail.

History
Both parents are high-ranking Vampire Hunters and are the parents of the Zero and Ichiru Kiryu. Despite them loving both their sons dearly, they felt that Ichiru's illness and lack of natural talent compared to Zero, would prevent him from becoming a Hunter and therefore focused more of their time on and generally preferred Zero over Ichiru. They were assigned to kill an ex-human vampire who they thought to be Level E due to the fact he had been an ex-vampire for so long. However, it turned out that, that ex-human wasn't a level E but, was the lover of Shizuka Hio and thus, drove her to insanity once finding this out. Shizuka killed both parents as revenge for slaying her ex-human lover, bit Zero and took Ichiru away as a result.

Trivia

 * Zero's mum is the first female hunter we see.