Age: 17
Height: 181cm
Blood Type: A
Affiliation: Day Class
Weapon: Bloody Rose
Zero is Yuuki's childhood friend and a student at Cross Academy. He serves as a Guardian and is part of the disciplinary committee. Zero has been living with Yuuki and Headmaster Cross, who acts as his legal guardian since the tragic loss of his family to a pureblood vampire when he was young. This event fueled his deep-seated hatred for vampires, driving him to become a Guardian in hopes of honing his skills to hunt them.
In reality, Zero is a vampire who was once human. He was bitten by Shizuka Hio, a pureblood vampire, during the attack on his family. Initially, he kept his vampiric nature hidden from Yuuki until his urges became uncontrollable. Unlike most vampires, Zero's body rejects blood tablets meant to curb their hunger. To maintain his sanity, he drinks Yuuki's blood, though he faces an inevitable fate of becoming a Level E vampire.
Zero wields the gun "Bloody Rose," gifted to him by Headmaster Cross, under the promise that Yuuki would kill him if he ever turned into a Level E vampire. His twin brother, Ichiru, arrives at Cross Academy with Shizuka Hio, seeking power against Rido Kuran. It is later revealed that Ichiru played a role in orchestrating the attack on their family, yet Zero still harbors love for his brother.
Upon discovering Yuuki's true identity as a Pureblood vampire from the Kuran lineage, Zero feels betrayed, believing she had deceived him. During Rido's assault on Cross Academy, Ichiru sacrifices his remaining life force to Zero, granting him full strength at birth but at the cost of Ichiru's life. Before Yuuki leaves Cross Academy, Zero declares his intent to hunt her down one day.
A year later, Zero continues his struggle with his vampiric urges, relying on Blood Tablets and hunting vampires at night to quench his thirst. Although distant initially upon reuniting with Yuuki, he still aids her when needed. After Kaname's sacrifice, Zero embraces Yuuki, urging her to let go of the past. Deciding not to run from his feelings anymore, he vows to wait for Yuuki, even if it takes years for her to reciprocate.
In the manga's conclusion, after a thousand years, Zero and Yuuki are shown leading a happy family life with two children. Yuuki remains by Zero's side until his last breath, visiting his family grave and leaving Bloody Rose as a memento while reminiscing about their shared memories. Despite their conflicts, Yuuki acknowledges how much happiness Zero brought into her life.
