Which Japanese music group was formed to produce theme music for the anime "Guilty Crown"?

Egoist is the Japanese music group that was formed specifically to produce theme music for the anime Guilty Crown. The group consists of singer-songwriter Chelly, who serves as the lead vocalist for Egoist. Known for their unique sound and emotional lyrics, Egoist has contributed several popular songs to the Guilty Crown soundtrack, such as "Departures (Anata ni Okuru Ai no Uta)" and "The Everlasting Guilty Crown."