Zero Kiryu

Zero Kiryu (錐生 ゼロ, Kiryū Zero) is one of the main characters of Vampire Knight. Zero is Yuki's childhood friend and the only other Cross Academy Guardian. Zero carries an anti-vampire gun named "Bloody Rose". Zero is the only Vampire Hunter/vampire who appears in the story.

Character outline
Even before becoming a vampire, Zero Kiryu was noted to be a talented vampire hunter due to being the stronger of a pair of rare twin hunters, his twin Ichiru.

Zero was born in the year of the Dog and his blood type is A. His favorite subject is social studies.

Appearance
Zero bears a tattoo, the school insignia, on the left side of his neck originally used to suppress his vampire side, later used to tame him. Zero is a casual dresser, usually wearing school uniform incorrectly with the vest and red tie exposed from under his black jacket and wears three silver earings on his right ear (top)and 2 on his left (bottom).

Personality
As a child, Zero was a quiet and gentle boy, to the point where Ichiru questioned whether he was even capable of being a vampire hunter. However after Shizuka's attack, Zero developed a strong distrust of vampires. Zero is a tsundere character, he sports a scary aura that makes most of the Day Class students wary of him. However, his innate nature is to protect humans, his cold attitude towards those he loves is likely to push them away and keep everyone at a distance.

Following his full awakening into a vampire, Zero harbors a great disgust towards himself because of inability to control his hunger and reliance on Yuki. His dismal outlook on his future and fear of what he might do causes him to give up and he almost kills himself with his own anti-vampire gun, Bloody Rose. He fights to ignore his hunger to the point of starvation rather than go to Yuki. He tries to help Yuki resolve her own problems and then impresses upon her that its alright for her to burden and use him because she owns him.

Zero is very hostile to the Night Class vampires when they threaten him, however he adopts his standard tsundere attitude when engaging them one on one while retaining a level of politeness. Zero expresses a great deal of anger toward Purebloods because of their mechanisms in his life in particular, he extends this hostility toward Yuki as well after she turns into a Pureblood vampire. In spite of this, his sense of duty override his issues ensuring his reliability and trustworthiness.

Background
Zero was born in a vampire hunter's family and had a identical twin brother named Ichiru. They, along with Kaito Takamiya, were trained as vampire hunters by Toga Yagari. Kaien later comments that they share a similar line of thinking thanks to this. Yagari lost an eye protecting Zero, when the still naive Zero makes himself vulnerable to ex-human vampire when the nurse turned wild and tried attacking Zero due to her Level E state. This was Zero's first lesson on the danger of seemingly innocent vampires.

Ichiru and Zero were once very close. Due to Ichiru's frail body, he could not keep up with training and lacked essential hunter skills. Ichiru constantly got sick, causing Zero to feel guilty about sharing their mother's love. One day Zero and Ichiru were taking a walk and Ichiru saw a woman sitting in a tree. Ichiru was in awe of how pretty she was, but Zero told Ichiru that it was a vampire and to stay away from her. A few days later, Ichiru ran off and Zero sensed the approach of the Pureblood vampire and ran to confront her. That vampire took Zero and bit him, hence turning him into a vampire. His parents came out in an attempt to save Zero but were killed. Zero at the time also believed his brother was killed.

After that attack Zero was taken in by Kaien Cross, the headmaster of Cross academy. His temperament turned cold and hostile, and at times cruel to the young Yuki who reached out to him. Her gentleness won him over, but Zero kept his affection for her to himself due to her loving Kaname, a vampire. However, Zero failed to reveal that he was going to turn into a vampire after Yuki revealed she was afraid of all other vampires. Over the next four years, the two became friends. Zero became her constant protector while Yuki mothered him, and acted as an older sister, though she is younger.

Ichiru Kiryu
Ichiru is Zero's twin brother.

Yuki Cross
Yuki and Zero became childhood friends after he went to live with Kaien after the massacre by Shizuka on his family. Yuki pledges to always be Zero's ally even after they part ways.

Shizuka Hio
Shizuka was Zero's Pureblood master when he was bitten by her when he was a child. She taunts and teases, when she comes to the Academy with Ichiru, about her being Zero's Master. He despises her for all she did; killing his parents and took his brother away as well as his own human self.

Powers
Zero is a highly talented vampire hunter and possesses the standard abilities to sense vampires from a great distance, accelerated healing and in spite of being a vampire, also able to wield anti-vampire weapons. Since becoming a vampire, Zero is able to distinguish purebloods from other vampires and an improved healing ability. After completing the fragment Zero is able to transform the Bloody Rose into its evolved state, where is literally becomes a part of his body, however the cost is using a high amount of his blood.

Trivia

 * Zero's first name is the kanji for rei, meaning "zero." In his last name, Kiryu, the ki means "auger" or "drill," and the ryu means "life."