Mao is the titular character of the series, a mysterious onmyoji who inhabits the Taisho period of early 1900s Japan. His life was irrevocably altered when he was cursed by a powerful and malevolent seven-tailed cat demon named Byoki. This curse granted him a form of immortality, causing his body to stop aging and compelling him to live for nine hundred years while relentlessly searching for the demon that afflicted him. Mao carries a deep sense of burden from his prolonged existence and the supernatural affliction that defines it. He is initially presented as a stoic and somewhat distant individual, possessing a calm and old-fashioned demeanor that reflects his centuries of life. His primary motivation is to find Byoki and break the curse that has bound him for nearly a millennium, a quest that also involves uncovering the truth behind the Gogyo Clan, a group of powerful sorcerers from his past. As a former favorite disciple of the Gogyo Clan's master, he was named successor, an honor that led his master to secretly order the other five disciples to kill him in order to draw out the strongest, a betrayal that deeply shaped his history. In the story, Mao serves as the central anchor of the supernatural mystery, acting as an experienced exorcist who investigates strange occurrences involving yokai and curses. His role becomes intertwined with that of Nanoka Kiba, a modern-day junior high school student who travels from the present to the Taisho era through a mysterious portal. The two form an uneasy alliance, with Mao providing his expertise in the supernatural while Nanoka brings her own mysterious connection to the curse. Key relationships include his bond with Nanoka, who develops a unique importance to him due to her shared curse and ability to aid him; his shikigami assistant Otoya, a paper spirit who serves him with loyalty; and his former fellow disciples Hyakka and Kamon, as well as the other members of the Gogyo Clan, whose connections to his past continually resurface. Over the course of the narrative, Mao undergoes development as his interactions with Nanoka gradually soften his stoic reserve, revealing a more complex individual shaped by tragedy and a long, solitary existence. In terms of abilities, Mao is a highly skilled onmyoji, or mystic, proficient in exorcism and supernatural combat. He wields a cursed sword called Hagunsei, which has the property of drinking blood and can only be safely wielded by someone who is also cursed by Byoki, which Nanoka discovers she can do. His arsenal also includes command over his shikigami, Otoya, and a deep knowledge of the elemental magic system based on the Gogyo (Wood, Fire, Earth, Metal, Water). His immortality, while a curse, also means he cannot die from age or most injuries sustained in his line of work, allowing him to persist in his centuries-long hunt.