Masaru is a preschool-aged boy who appears at the beginning of the Spirit Detective Saga. He has brown hair and hazel brown eyes. When Yusuke Urameshi first encounters him, Masaru is wearing overalls and playing soccer in a traffic-heavy area of the city. He accidentally kicks his ball into the street and runs after it without looking, putting himself directly in the path of an oncoming car. Yusuke shoves Masaru out of the way, taking the fatal impact himself. According to Botan, Masaru had been destined to be hit by that car and emerge completely unharmed, a miraculous outcome, but Yusuke’s intervention disrupted that course and led to Yusuke’s death instead. Masaru later attends Yusuke’s wake, dressed in a tieless suit, where he is seen crying alongside other mourners. His role in the story is that of a catalyst: his near-accident and Yusuke’s selfless act set the entire series in motion, as Yusuke’s sacrifice earns him a second chance at life and his appointment as a Spirit Detective. Masaru has no further appearances or character development beyond this introductory incident, and he possesses no notable supernatural abilities. His personality is not explored in depth beyond the naivete typical of a young child unaware of mortal danger. The key relationship is the one-sided life‑saving act performed by Yusuke, which defines Masaru’s significance to the plot.