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.

Appearance
Zero bears a tattoo, the Hunter's Seal, 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 left ear (top) and 2 on his right (bottom). His hair is a pale, silvery white, with impressively pale skin, and his eyes are pale purple or lavender coloured.

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 retaining a level of civility. 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.

One day in winter, 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, 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 Kiryu is not only Zero's twin brother also his rival. Ichiru had been a sick child since he was born. He had Zero take away his egg when they were in their mother's womb, as the hunter legend says. Zero, thinking that Ichiru died because of Hio Shizuka, mourned him. Ichiru comes back and injures Zero for a short time with a human weapon. After Hio Shizuka died, he came back to join the day class in order to take Shizuka's revenge on Rido. He was injured in the process of trying to kill him. Ichiru came to the basement that Zero was taken and shot him in the shoulder and Zero thinks what he had thought about his mother giving love to both of them.But when Ichiru dies in Zero's hands, Ichiru confess every thing. Only then does Zero tell Ichiru that since their Mother and Father died, Ichiru is the most important person to him.

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 became Zero's master after the pureblood bit him during her attack on his family. She claims she did it because she knew that Zero would challenge her and become strong. Shizuka meets Zero again 4 years later at Cross Academy in the guise of Maria Kurenai, but thanks to Yagari's warning, Zero recognises who she really is. She taunts him about her being Zero's Master and his being under her command. He despises her for all she did; killing his parents and took his brother away as well as his own human self. When Yuki bargains her humanity for Zero's life, Zero overcomes his master's commands and manages to wound her. Zero had every intention of sacrificing his life to kill Shizuka, but is prevented by Yuki and though the final kill was not his, he was blamed for it by the council and Ichiru.

Kaname Kuran
Zero disliked Kaname on sight recognising him as a vampire and has been his rival ever since.

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. Kuran Kaname explains that after he eats Ichiru he would become the world's strongest hunter. He, then, explains that he has the blood of Kuran Yuki because Yuki was a pureblood, Kaname and Shizuka was as well. 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."