Akira Kaburagi is introduced as a seemingly typical high school student, but this ordinary facade conceals a much deeper and more extraordinary identity. At the start of the story, Akira suffers from amnesia, unable to recall any events from roughly a year and a half before the narrative begins. This loss of memory has left him in a somewhat apathetic state, generally content with his simple, everyday life as a student in Japan. However, his world is turned upside down with the sudden appearance of Mina Tepes, the young-looking princess of all vampires, who has just publicly announced the existence of her kind to the world.

Upon meeting Mina again, Akira is flooded with violent headaches and the first of many returning memories, revealing that his past is deeply intertwined with hers. He discovers that he is not human but a member of the Earth Clan, a race of werewolves sworn to serve the vampire queen. More than that, he is Mina's chosen guardian and bodyguard, a role he accepted due to a promise he made to her when they were both children. This central promise binds his entire existence to her protection and well-being. His motivation shifts completely from living a peaceful school life to embracing his sworn duty, standing as the first line of defense against the numerous factions—both human and vampire—that seek to destroy Mina and her newly established Bund.

Akira’s personality is defined by his unwavering loyalty and sense of duty. Once his memories return, he commits himself entirely to Mina, willing to face any danger to ensure her safety. This devotion is the core of his character, driving him to fight and even risk his life against powerful enemies. His key relationships revolve primarily around Mina Tepes, to whom he is bound by oath and a childhood promise that carries the weight of a marriage vow. He also shares a significant connection with his classmate, Yuki Saegusa, a human who cares deeply for him and is initially in love with him, creating a complicated dynamic as Akira's memories of Mina resurface. Yuki is one of his closest friends and serves as a link to his human life and the world he is leaving behind.

Throughout the story, Akira undergoes significant development. He begins as an amnesiac teenager, confused and detached, but evolves into a fierce and capable warrior who fully accepts his heritage and responsibilities. This development is often tied to his physical abilities, which are among his most notable traits. As a member of the Earth Clan, Akira is a werewolf, granting him the power to transform into a powerful wolf-like beast. In this form, he possesses superhuman strength, speed, and resilience, making him a formidable combatant in the violent conflicts that plague the Bund. His journey is one of self-discovery, where he must reconcile his human memories with his monstrous heritage and the ancient, binding promise that defines his fate.