She is Yukimura's younger sister. Her debut in the anime occurs in episode 20. Upon seeing Usui, she instantly addresses him as her "ouji-sama" (prince). Following a date where Misaki orchestrates various 'methods' to make Yukimura appear more prince-like, Ruri concludes that Takumi-sama's 'princess' is not her. Initially, Ruri disliked revealing to others that Yukimura was her brother (a fact that deeply upset Yukimura), but she eventually recognizes the 'prince' within him, and she and Yukimura reconcile.
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