Zero Kiryuu

Zero Kiryuu is one of the main characters from the Vampire Knight anime and manga.

Zero is both an ex-human vampire and a vampire hunter. Zero is the older twin brother of Ichiru Kiryuu, Yuuki Kuran's boyfriend, and the biological father of Yuuki's daughter Ren Kiryu.

Appearance
Zero is a tall young man with silky silver hair, snowy-white skin and lavender eyes, the latter varying in shade from the manga to anime. Zero is a casual dresser and is usually wearing his school uniform incorrectly, with the vest and red tie exposed from under his black jacket. He also wears five silver earrings; three on his left ear cartilage (top) and two on his right (bottom). Zero bears a tattoo, the Hunter's Seal, on the left side of his neck, originally used to suppress his vampire side, and later used to tame him. He has grown taller as the series progresses.

Zero is considered to be attractive and handsome, by both Day and Night Class students.

Personality
Zero is generally a composed person. He is also protective of Yuki. Although he comes across to other students as cold hearted and hostile, he is friendlier towards Yuki and occasionally shows his true emotions to her. However, when Yuki was revealed to be a Pureblood vampire, he became cold and hostile, especially towards Kaname and Yuki. Though he appears otherwise, he is a gentle and kind person. Due to his childhood, he builds barriers around himself, and does not let these barriers down all the way, even for Yuki. Despite this, he has a kind heart which longs to protect humans, and he will never betray the ones he holds dear.

As a child, Zero was once a quiet and gentle boy, to the point that Ichiru questioned whether or not he was even capable of being a vampire hunter. However, after Shizuka's attack, Zero developed a strong hatred towards vampires. Zero is a tsundere character; he sports a scary aura that makes most of the Day Class students wary of him. He can also glare in a way that even Kaname Kuran calls scary. However, his innate nature is to protect humans, and his cold attitude towards those he loves is likely to push them away and keep everyone at a distance.

Following his full awakening as a vampire, Zero harbors a great disgust towards himself because of his inability to control his hunger and his reliance on Yuki. His dismal outlook on his future, and fear of what he might do if he becomes a level E, causes him to give up and he almost kill himself with his anti-vampire gun - the Bloody Rose. However, Yuki arrives just in time to stop him. At times, he would rather ignore his hunger to the point of starvation instead of going to Yuki for help. 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 hostile towards 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 towards Purebloods because of their mechanisms in his life in particular, and because of this, he extends this hostility toward Yuki as well after she reawakens into a Pureblood vampire. In spite of this, his sense of duty overrides his issues, ensuring his reliability and trustworthiness.

A gifted hunter who is intelligent, athletic, and good-hearted, Zero nevertheless has a difficult time thinking of himself or any other vampire as anything but a monster. He struggles both with his desires for blood and his equally strong desire to kill vampires. Because of all this, Zero can be very closed off, as well as being difficult to understand or get close to, especially since he has a habit of not expressing his true feelings. These true feelings are hidden behind a cold, composed personality. He has a lot of attitude, is not at all impressed or easily controlled by higher class vampires, and he also carries a positively burning hatred of all Purebloods. He often acts as if he doesn’t care about anything in order to hide all the scars and pain inside him that have nowhere to go. When not about his duties or in class, he can frequently be found in the Cross Academy stables with the fiery horse, White Lily, with whom he seems to share a special affinity. He is also quite a good cook which was admitted even by Aido, who is known for being quite picky.

Following his revelation towards the end of Vampire Knight and the aftermath of Kaname's sacrifice, Zero is shown to have matured in his perspective on vampires and Purebloods alike. His acceptance of Ai and his unwavering love and loyalty towards Yuki signifies that, unlike in the past, his fierce hatred for Purebloods has subsided greatly. As Zero has always been shown to have a paternal nature, he naturally bonds well with Ai and becomes a father figure in her life. It's this paternal nature that eventually leads to his demise. Despite all of this, he still shows some reservation on revealing his true feelings to Yuki, something that seems to be a mutual issue.

Abilities
Zero is a vampire hunter who was chosen by Kaname to become a Pureblood killing machine. Zero possesses the standard abilities to sense vampires from a far distance, accelerated healing and in spite of being a vampire, is also able to wield anti-vampire weapons. Since he became a vampire, Zero is able to distinguish Purebloods from other vampires and has gained improved healing abilities. Kaname tells Zero that after he devours Ichiru's blood, he would become the world's strongest hunter. He then explains that since he has drank from Yuki's since she was a Pureblood, as well as Kaname and Shizuka's blood, it has made him the most powerful vampire hunter. After completing the fragment, along with Ichiru now being deceased, Bloody Rose has now become a part of his body, growing vines that can easily kill vampires; although it requires a high dosage of his blood to do so.

Zero's beast form made its first appearance in 40th Night after he drank Ichiru's blood and its shadow was seen on the wall. In 82nd Night, the beast form is released in a new attack from Bloody Rose when Zero fights Kaname shortly after drinking Sara Shirabuki's blood.

Bloody Rose
The Bloody Rose is an anti-vampire gun that Zero keeps behind his school uniform blazer. Zero is able to transform his gun, Bloody Rose, into its evolved state after consuming his twin brother, Ichiru. Bloody Rose literally becomes a part of his body. However the cost is using a high amount of his blood. In both the manga and anime, Zero had used Bloody Rose to kill Rido.

Origins of Bloody Rose
Bloody Rose was a weapon born from the sacrifice of a Pureblood vampire, The Hooded Woman, 10,000 years ago. Artemis and Bloody Rose were originally Kaname Kuran's personal weapons during the wartime before he gave them to Kaien Cross to be in-charge. They were later passed down to Yuki Kuran when she became the school guardian and Zero Kiryu when he became a vampire hunter respectively.

Trivia

 * Zero's given name is usually read in Japanese as rei, which means zero. His surname, Kiryu, consists of the characters for auger (kiri) and life (nama).
 * Zero Good at: Sciences,Cooking, Horseback Riding, Marksmanship.
 * Zero Favorite Food: Ramen with Salt Broth.
 * Zero Hobbies: Eating and sleeping.
 * Zero Respects: His Master.
 * Zero Taste In Women: Cool older women (Flat -Chested women are out of the Question).
 * Zero Favorite Fashion : whatever (like Yuki Chooses for him).
 * As Kaname notes, kindness is a trait Zero had even before he was born. Ichiru was the weaker twin, and should have been consumed by Zero; however, Zero did not, just a sign of how kind he can be.
 * Zero's classification as a vampire is up to debate. Whether he is considered a Level D or C is unknown.