Kōji Amami, the enigmatic owner of the Rainy Color café central to the series, embodies a free-spirited and unpredictable demeanor. His frequent international travels fuel a passion for discovering eclectic souvenirs, antiques, and artwork, which he curates within the café’s ambiance. A spontaneous trip to Hawaii during the fifth season triggers pivotal narrative shifts, as his absence prompts his daughter to temporarily manage the establishment.

Driven by wanderlust, Kōji collects trinkets and cultural artifacts from his journeys, reflecting an insatiable curiosity for the unfamiliar. His impulsive ventures often ripple into the lives of others, inadvertently entangling them in his unpredictable escapades. While his personal history remains undefined across documented media, his consistent role as a catalyst for events underscores traits of mystery, adventurous spontaneity, and a distinctive flair for transforming global treasures into conversational centerpieces at Rainy Color.