EGOIST was a notable pop music duo that emerged in 2011, comprising songwriter Ryo from Supercell and vocalist Chelly. Initially formed to create theme music for the acclaimed anime series Guilty Crown, the duo expanded their musical repertoire beyond the show’s conclusion. EGOIST initially existed as a fictional band within Guilty Crown, featuring the character Inori Yuzuriha as its vocalist. Ryo, the innovative composer and producer from Supercell, meticulously selected Chelly from over 2,000 applicants to bring EGOIST’s music to fruition. Embracing the persona of Inori during performances, Chelly preserved an enigmatic aura by concealing her true identity. The duo gained significant recognition through their contributions to various anime series. In August 2023, EGOIST announced their disbandment, culminating in final concerts in Osaka and Yokohama. Their last performance took place on October 9, 2023, at Pacifico Yokohama, signifying the conclusion of their musical journey, while Chelly has since pursued her career under the name Reche.