Mizuki is the daughter of Mazuchima and the fiancée of Yuuma Asuka, two figures central to the Chi-ryū, or Earth-style, faction of onmyōdō users. She is a talented Chi-ryū toujinshi, a practitioner who commands shikigami through a device called a Drive. Her appearance is marked by very long blue hair and red eyes. Mizuki’s personality is defined by her unwavering loyalty to her father and her fiancé; she is deeply dedicated to their causes and is constantly striving to prove herself as a capable and powerful warrior. This drive to demonstrate her worth stems from a desire to be recognized as a truly skilled toujinshi within the Chi-ryū hierarchy. Her role in the story is primarily as a supporting character aligned with the Earth-style forces, often participating in battles against the Ten-ryū, the Heaven-style faction. Her key relationship is with Yuuma Asuka; she is betrothed to him and holds a deep, unconditional loyalty to him, even when circumstances put her own life at risk. At one point, she sacrifices herself to save Yuuma, an act that results in her losing her memories. However, after witnessing Yuuma’s sincere heart and enduring dedication, she eventually begins to regain her feelings for him and redevelops a compassionate bond. In terms of abilities, as a Chi-ryū toujinshi, Mizuki is proficient in summoning and commanding shikigami, using seals and onmyōdō techniques to fight. She is also noted for her courage and willingness to endure great personal harm in battle. Her development throughout the series centers on moving from a purely loyal follower of her family and faction to someone who acts out of personal growth and genuine emotional connection, particularly through her renewed relationship with Yuuma.