J-pop singer Seiko Oomori was born on September 18, 1987, in Matsuyama, Ehime Prefecture. She became involved with the underground music scene in 2007 while still attending Tokyo's Musashino Art University. In the following years, she and her band Seiko Oomori & The Pink Tokarev lashed out against the predominance of Japanese idols on the pop charts, helping create the "anti-idol" scene that would later give way to the Kawaii metal movement. After independently releasing the albums Mahō ga Tsukaenai nara Shinitai and Zettai Shōjo in 2013, Seiko Oomori landed a deal with Avex Trax and issued her major-label debut Sennō in 2014. The album reached Number 18 on the Oricon charts and was followed by other well-received efforts such as Tokyo Black Hole (2016) and Kitixxxgaia (2017). In 2018, she created, produced, and participated in the idol group ZOC ("Zone of Control"), whose first full-length PvP appeared later that year. Kusokawa Party, her sixth studio album, also saw the light in 2018 and entered the Top 10 in Japan. Over the next few years, Seiko Oomori continued her slow transition toward a more mainstream sound on the albums Kintsugi (2020), Persona #1 (2021), and Cho Tengoku (2022), which hit Number 23 on the Billboard Japan Albums chart.