Ikuyoshi Sasaki, also known by his source name Iku, is a character who appears in the second season of the anime. His background is rooted in the nightlife industry, as he was formerly a host and a colleague of Haru Kaideki during Haru's time working as a host. After leaving that profession, Sasaki chose to follow Haru, demonstrating a strong sense of loyalty and admiration for him. He began working at Haru's café, Cafe & Bar White Fang, as a staff member.

In terms of personality, Sasaki is characterized by a friendly and lively demeanor. His motivations are closely tied to his respect for Haru, as he admired him enough to change his own career path. He is part of the supportive work environment at the café and maintains a connection to his family roots. His family are farmers in the Chiba prefecture, and they supply the café with fresh vegetables, a detail that links his personal background directly to his role in the story.

His key relationships are primarily with his coworkers and the characters connected to the café. He shares a warm and familiar rapport with the other staff, notably referring to Ren Kaideki affectionately as Ren-Ren. His role in the narrative is that of a supporting character, contributing to the daily life and operations of White Fang. The series does not highlight any notable or exceptional abilities for him beyond his professional skills as a former host and his current competency as a café employee. Information regarding his development, as well as specific details like his exact age or birthday, are not provided.