Yuzuru Nishimiya is the younger sister of Shoko Nishimiya, approximately three years her junior. She grew up in a household with her mother Yaeko Nishimiya, grandmother Ito Nishimiya, and Shoko, witnessing her sister's struggles with deafness and bullying. From an early age, Yuzuru adopted a fiercely protective role toward Shoko. She cut her hair short, presented herself with a boyish appearance and mannerisms, and used the masculine pronoun "ore" in her Japanese speech. This deliberate androgynous presentation led others, including Shoya Ishida upon their first meeting, to mistake her for a boy. She cultivated this identity partly because her mother Yaeko had initially considered making Shoko appear boyish for protection; Yuzuru took on that role instead. Yuzuru harbored deep resentment toward Shoko's elementary school bullies, especially Shoya Ishida. Her protectiveness manifested confrontationally: she lied to Shoya, claiming to be Shoko's boyfriend to drive him away, and later orchestrated his school suspension by photographing him illegally retrieving Shoko's notebook from a river and posting the image online. This act caused a significant argument with Shoko, prompting Yuzuru to run away from home. Shoya offered her shelter, an event that marked the beginning of a shift in their relationship as she observed his genuine remorse and efforts to change. Academically disengaged, Yuzuru frequently skipped middle school to pursue photography, a hobby inspired by a camera gifted from her grandmother Ito. She focused almost exclusively on photographing dead animals and insects. This practice was later revealed as a desperate attempt to graphically illustrate the gruesomeness of death and dissuade Shoko from suicidal thoughts stemming from years of bullying and self-blame. She blamed herself when this strategy failed, particularly after Shoko's suicide attempt during a fireworks festival, viewing it as her personal failure in managing her sister's mental state. Her relationship with her mother Yaeko was strained, perceiving her as distant and uncaring. In contrast, she shared a close bond with her grandmother Ito, who understood her deeply and expressed concern that Yuzuru neglected her own needs while focusing solely on Shoko. Ito's advice for Yuzuru to "learn more about herself" resonated strongly, especially after Ito's death. This loss, coupled with Shoko's near-suicide and Shoya's subsequent coma after rescuing Shoko, prompted significant personal reflection. Yuzuru tore down her wall of dead animal photographs, acknowledging the ineffectiveness of her approach to "saving" Shoko. As Shoko began showing signs of recovery and independence, Yuzuru committed to personal growth. She accepted Shoya's offer to tutor her academically, aiming to improve her grades and reduce her sister's worries, symbolizing her return to formal education and steps toward self-investment. Her bond with Shoya evolved into a trusting, sibling-like relationship; she confided in him about her grandmother's death and supported his reconciliation with Shoko, even encouraging a potential romantic relationship between them. She observed that Shoya's advice reminded her of Ito's wisdom. By the story's conclusion, Yuzuru had enrolled in a girls' high school alongside Naoka Ueno and Miyoko Sahara. She continued her photography with a digital camera but shifted away from her earlier morbid focus. Her photography skills gained recognition, winning first place in a local contest. She attended the Coming of Age Day ceremony, symbolizing her integration into societal milestones and ongoing personal evolution.