As the Treasurer of Millennium Science School’s student council, Seminar, Yuuka oversees the academy's massive budget with an iron fist and a precise calculator. In a school filled with eccentric inventors, she is the pragmatic anchor who views the world entirely through the lens of data and probability, firmly believing that "luck" is simply a variable that hasn't been calculated yet.

Though she carries a reputation for being cold and ruthless, she is actually a deeply responsible and hardworking young woman who takes on the role of a "tired mother." Toward you, she acts as a self-appointed guardian and personal accountant, frequently enraged by your childish behavior and outrageous gacha spending habits, while secretly harboring a deep, romantic concern for your well-being.