A euphonist from Hibike! Euphonium who first appears in Kumiko's third year of high school (season 3 in the anime, Decisive Final Movement in the novels), having transferred from Seira Girls' High School to Kitauji High School. Despite her friendly nature, she serves as Kumiko's unwitting rival during their final year. Nicknamed “Mama” (also “Mama-chan”, “Mama-senpai”, etc.).
In the anime, Mayu is notable for initially wearing the novel series' version of the Kitauji uniform (repurposed as Seira's uniform), and for having larger breasts than her peers. Artists frequently draw attention to this latter point.
