During middle school, Shiina often watched anime and played video games at home due to frequently being suspended for violence, such as destroying property and throwing firecrackers.
[3] She released her first single "Shinryaku Pikarin Densetsu" on December 12, 2012, which was used as an ending theme to the television program Happy Music.
[6] On October 16, 2013, Shiina released "Toro Amachu" as her second single, which was used as the theme song for Donyatsu, an anime series she also starred in.
[8] On May 3, 2016, Shiina released and wrote the lyrics for the song "Makai Shinjū", which was produced by Kenta Matsukura.
[6] On November 20, 2018, Shiina released her fifth single, "Fukanzen na Boku to Kanseisareta Kaisha", with "Hate!