Yu Igarashi manages model Kokoro Hasegawa's career at the Bon Rouge agency. A former model herself during her youth, she shares a long-standing professional relationship and friendship with Shizuku Naruoka, dating back to their teenage collaboration at Bon Rouge. Her name, written in kanji as 五十嵐 優, combines "fifty" (五十) and "storm" (嵐) for "Igarashi," while "Yu" (優) signifies "excellence," "superiority," or "gentleness." She possesses neck-length black hair and blue eyes. Her documented role centers on managing Kokoro's modeling commitments.