Yu Igarashi represents model Kokoro Hasegawa as her agent at the Bon Rouge agency. Her own background includes experience as a model, working alongside Shizuku Naruoka at Bon Rouge during their younger years; this shared history defines their relationship as friends and former colleagues. Within the narrative, Yu actively guides Kokoro's career path. She approaches Ikuto Tsumura, aiming to persuade him to convince Kokoro to prioritize modeling over fashion design. This intervention occurs while Ikuto faces challenges related to his mother's health. Yu's actions demonstrate her role in managing Kokoro's professional trajectory and her vested interest in directing it. Her documented interactions remain focused on her professional capacity as an agent and her past connection to Shizuku.