Yui Kurumizawa, also referenced as Yue Kurumizawa in certain contexts, attends Shinonome Academy alongside the protagonist Itsuki Sonomiya. As the heir to the affluent Kurumizawa corporation, she operates under her grandfather's mandate to secure a suitable fiancé. This directive compels her to seek a man unaffected by the global impotence pandemic, a quest she initially approaches with skepticism. Her physical traits include waist-length blonde hair and distinct yellow eyes, commonly showcased in her school uniform attire. A turning point arises during an accidental physical encounter with Itsuki, where she detects his unique physiological responsiveness. This discovery dispels her doubts and triggers decisive action: she formally proposes marriage to him in a private classroom setting, revealing her direct and goal-oriented nature. Her interactions frequently involve rivalry, particularly when Akari Himeno disrupts her private moment with Itsuki. This incident positions her within the competitive dynamic among women aware of Itsuki's secret. Throughout the narrative, her corporate heiress status and pursuit of a fiancé remain central motivations for her actions.