Shimei Ryomou is a third-year student at Nanyo Academy and one of its elite Big Four fighters. Her striking appearance features short dark blue hair, green eyes, a beauty mark on her left cheek, and a modified eyepatch obscuring her left eye. She typically wears a school uniform or a blue miniskirted French maid outfit in combat, paired with fingerless gloves and combat boots. Initially reserved, stoic, and detached, Ryomou displays sadistic tendencies during fights, favoring submission techniques that inflict pain. Her combat expertise centers on grappling, joint locks, throws, and handcuff-based tactics, supplemented by chi blasts. After her friend Tokubou Teifu suffered blindness and paralysis, her demeanor hardened, though bonding with Hakufu Sonsaku later softened her rigid exterior. Ryomou shares a long-standing friendship with Teifu and Genpou Saji, harboring unspoken romantic feelings for Saji. Three years before the main events, she intervened in Ryuubi's dragon-awakening crisis, absorbing Ryuubi's dragon spirit into her left eye. This symbiotic fusion grants rapid healing from fatal injuries, with the dragon's power sealed by her eyepatch and hidden from others. Ranked as a B-class fighter, Ryomou employs leg-focused submissions and chi manipulation, executing techniques like "Tenchi Hakurogeki." The dragon's influence sporadically amplifies her aggression, creating a minor split personality that contrasts her stoicism with psychosexual impulses. Her combat style efficiently incapacitates opponents. Key developments include early clashes with Hakufu Sonsaku that evolve into mutual respect. She participates in the Battle of Chibi, defeating Myosai, and the Great Fighters Tournament in the "Xtreme Xecutor" arc. Driven by loyalty, she undertakes a solo mission to retrieve the Dragon Jade for Hakufu, sustaining severe injuries that trigger a dragon awakening to overpower Teni. Post-recovery, she works with Hakufu at a cosplay café, adopting a cat-maid persona with a heart-shaped eyepatch. Her physical evolution includes transitioning from long to short hair and an unexplained shift from blue to black hair in later manga volumes. Her concealed eye changes from pale gray to gold with hellish pupils across seasons, while her eyepatch's design visually evolves.