Reol is a Japanese singer, composer, lyricist, and record producer. She began creating and releasing music onto Nico Nico Douga and YouTube in 2012, achieving recognition for writing and performing viral Vocaloid songs. She released the album Gokusaishiki independently, which reached the top ten on the Oricon Albums Chart. Reol signed with the record label Toy's Factory in 2015, and in 2016, she formed the J-pop group REOL, composed of her long-time collaborators GigaP and Okiku, where she served as both its namesake and lead vocalist. Their debut album, Sigma, was released the same year to widespread success and acclaim, peaking at 6 on the Oricon Albums Chart, and 9 on the Billboard Japan Hot 100. In 2017, the group announced they intended to disband, and after their final live performance, they released the extended play Endless EP before officially disbanding. Following the disbandment of REOL, Reol signed with Victor Entertainment in 2018, resuming her career as a solo artist and releasing the album Jijitsujo that same year. Giga-P still frequently collaborates with her as a producer, and Okiku has continued to contribute to live visuals and some music videos.