Kosuke Tamiya is a male college student with an interest in photography. He is identified as the primary love interest of Chako. His presence is noted during a summer beach trip, where Chako, aided by other cosplay club members, attempts to confess her feelings to him. He is also present during a challenge from the rival Shin-Takarazuka Academy Cosplay Club, where their leader, Ranko, expresses a romantic interest in him. This sparks tension and motivates Chako to personally engage in the subsequent cosplay competition.