Japanese pop singer and songwriter from Itami, Hyōgo. She began her professional musical career at age 21 as a concert backup singer. From almost the very beginning of her career, Masami has sung themes for anime television and movies. She is especially well known for her songs from Revolutionary Girl Utena, Tales of Eternia The Animation, Slayers, Sorcerer Hunters, Di Gi Charat, Magic User's Club, Jungle de Ikou!, Akihabara Dennou Gumi, Ray the Animation, He Is My Master and Yu-Gi-Oh! Duel Monsters. She has performed material for more than 50 singles and 20 albums to date. Okui hosts @Tunes, an anime music news program, on the Japanese anime television network Animax.