Itsuki Sumeragi, a first-year Hyakkaou Private Academy student and former Hana-class Student Council member, wields influence through her family’s Japanese toy empire, employing its resources to craft tailored gambling tools and exert financial pressure. Her chin-length blonde or brown hair frames a green hairband and blue eyes, while her nails showcase intricate star or club suit designs—later replaced by bandages from self-inflicted gamble injuries. She dons the academy’s red blazer over a black-striped white shirt, pleated skirt, and star-patterned stockings. Initially manipulative and sadistic, she hoards opponents’ fingernails as trophies, viewing them as emblems of dominance over social hierarchies. Her reliance on heat-reactive cheating cards from her family’s company crumbles when Yumeko Jabami exposes her during Double Concentration, costing her Council position. Post-defeat, she masks her ambition with false camaraderie toward Yumeko, gradually cultivating authentic loyalty. During Choice Poker against Kaede Manyuda, she stakes her nails and financial stability, aiding Yumeko in dismantling Kaede’s defenses. This gamble sparks empathy, leading her to care for Kaede post-defeat, claim his life plan, and persist in supporting his recovery despite his rejection. In the election’s Public Goods Game, she betrays allies like Miroslava Honebami to sway outcomes for Kaede, forfeiting accumulated votes and exiting the race. Her motives evolve from opportunism to a mix of strategic ambition and emotional commitment to Kaede’s resurgence, marking her transition from cowardice to self-sacrifice. A spin-off reveals her tentative friendship with Mary Saotome and nightmares of Yumeko’s fixation on her nails, echoing past trauma. By the series’ end, she discards nail art entirely, symbolizing her rejection of status symbols and embrace of transformed priorities.