Egoist is a Japanese pop music duo consisting of songwriter Ryo of Supercell and vocalist Chelly. Originally formed to produce theme music for the 2011 anime television series Guilty Crown, the group continued creating other songs after the end of the series including themes for other anime television series including Psycho-Pass and Kabaneri of the Iron Fortress. Egoist's debut album Extra terrestrial Biological Entities was released in September 2012.In 2011, Ryo of Supercell was tasked with composing theme music for the anime television series Guilty Crown.That year, Supercell held auditions from May 25 to June 19 for the vocalist on the band's third studio album Zigaexperientia (2013), and Ryo was also searching for the vocalist of Egoist, a fictional band featured in Guilty Crown. Out of about 2,000 candidates, then 17-year-old female singer Chelly was chosen to sing under the persona of the band's vocalist Inori Yuzuriha.Egoist's debut single "Departures (Anata ni Okuru Ai no Uta)" (Departures －あなたにおくるアイの歌－ Departures －Anata ni Okuru Ai no Uta－?, "Departures (The Love Song for You)) was released on November 30, 2011; the song was used as Guilty Crown's first ending theme. Egoist's second single is "The Everlasting Guilty Crown" released on March 7, 2012; the song was used as Guilty Crown's second opening theme. Included on Egoist's first two singles are remixes of the title songs by Boom Boom Satellites. Egoist's debut album Extra terrestrial Biological Entities was released on September 19, 2012.
Egoist's third single "Namae no Nai Kaibutsu" (名前のない怪物?, "The Nameless Monster") was released on December 5, 2012; the song is used as the first ending theme to the 2012 anime series Psycho-Pass.Egoist's fourth single "All Alone With You" was released on March 6, 2013; the song is used as the second ending theme to Psycho-Pass. Egoist released the digital single "Suki to Iwareta Hi" (好きと言われた日?, "The Day I Was Told I Love You") on November 6, 2013. Egoist's fifth single "Fallen" was released on November 19, 2014; the song is used as the ending theme to the 2014 anime series Psycho-Pass 2. The band's sixth single "Reloaded" (リローデッド?) was released on November 11, 2015; the song will be used as the theme song to the anime film Genocidal Organ. Egoist's seventh single "Kabaneri of the Iron Fortress" was released on May 25, 2016; the song is used as the opening theme to the 2016 anime series Kabaneri of the Iron Fortress. Egoist will move to the Sacra Music record label under Sony Music Entertainment Japan in April 2017.