Zero Kiryuu

Yuuki’s childhood friend, Zero is also a Guardian and likewise on the disciplinary committee. Yuuki has been taking care of him as her little brother since he was brought into their home (the Headmaster’s). His family, a line of vampire hunters, was murdered by the pure blood vampire Shizuka Hio when he was young. He harbors a deep hatred for vampires and claims to have taken on the role of Guardian to learn to hunt them better.

In truth, Zero was bitten during the attack on his family, and have kept the secret that he was a vampire from Yuuki until he was no longer capable of controlling his vampiric urges.

Zero’s body rejects the blood tablets that most vampires take to control their hunger. Drinking Yuuki’s blood helps him maintain his sanity, but he is destined to become a Level E vampire eventually. He has started to accept his feelings towards Yuki and has gone as far as to almost kissing her. Zero’s weapon is the gun “Bloody Rose,” given to him by Headmaster Cross. He made Yuuki promise that if he becomes a Level E vampire, she will kill him with that gun.

After the time skip of about one year Zero has been living off of Blood Tablets; after the incident of Yuki being awakened as her true self (being that she is a pure blood and Kaname’s fiance); the entire school being attacked by Vampires; and Zero “eating” his twin brother in order to gain his full power back. Zero has become a strong and very powerful being…even a great threat to the Pure Bloods. He continues to go to school (with reluctance), but cannot stay in the dorms due to him “hungering uncontrollably…by night” and hunts vampires at night to quench his thirst all the more on chapter 50. He can now control himself without Yuki’s blood, but it is still difficult.His personality is still the same, but he still loathes the Pure Bloods to the point it makes him nearly insane.

After Kaname threw his heart into the furnace, he tells Yuki and Zero that they should be together. After the war, he hugs Yuki and tells her to let go of everything that has happened. He also decided not to run away from his own feelings anymore, and that he’ll wait for Yuki to say that she’ll go with him even if it’ll take years for her to say it. After a thousand years, it is seen in the manga that Zero and Yuki had a happy family life and raised two children together. Yuki stayed by Zero’s side until his last breath, and after, she went to his family’s grave and left Zero’s bloody rose (as his own grave because he turned to dust) and while reminiscing her memories of Zero, she said that though they had a lot of quarrels, Zero really made her happy.