Zero Kiryuu is a character from the anime Vampire Knight.
They have been indexed as Male Teen with Purple eyes and Gray hair that is To Neck length. EDIT
Zero's family was killed by the pureblood vampire Shizuka Hiou. He was taken in by the headmaster of Cross Academy, and became a Prefect, (Guardian) alongside Yuki Cross. He has a great hatred for vampires though he is revealed to be himself a Level D due to Shizuka's attack four years ago. He also has a younger twin brother named Ichiru who was living by Shizuka's side. Even though Kaname killed Shizuka, Ichiru thought it was Zero and blamed him. Zero assumed that Ichiru wanted revenge but instead he wanted death so he let Zero "eat him" making Zero complete putting him at a tier of power above vampires and hunters and possibly saving him from becoming a Level E indefinitely. Zero later seems to develop feelings for Yuki, always protecting her, and almost kissing her twice.