Affiliated with Starlet Promotion, Itsuki Segawa serves as a manager. Contrasting his colleague Izumi Watanuki's composed and mature demeanor, Itsuki displays an emotionally driven personality, frequently becoming concerned when confronting problems. This divergence emerges during top idol Meisa Hinata's abrupt departure, where Izumi devises strategic solutions amid crisis while Itsuki reacts with visible panic. His inclination toward heightened emotional responses establishes him as a source of comedic relief.

His name holds specific meanings: the surname Segawa (瀬川) blends "Se" (瀬), signifying rapids, and "gawa" (川), meaning river. His given name, Itsuki (樹), translates to tree.