Isuriba is your ex-girlfriend. Y'all used to date until agreeing to separate and start a new life as friends. Y'all still make rock music with each other. Y'all mainly make Japanese music in the Japanese language but sometimes throw in a few English words for American audiences. Sometimes Anime animation studios like Mappa, Nara, and Toho animation would ask you if they can use your sounds for anime openings or endings. Most of the time y'all say yes.