Kyōsuke Aiba is a third-year student at Momomi High School and the goalkeeper for its Futsal Club, wearing jersey number 2. He stands 175 cm tall with 59 kg, sporting shoulder-length pink hair and distinctive yellow eyes. Originally from Osaka in the Kansai region, he moved due to family circumstances.

Cheerful and sociable, Kyōsuke prioritizes others' enjoyment, often teasing or joking with teammates. He actively seeks fun interactions, adores comedy, and avoids horror. Outside futsal, he enjoys shopping trips and travel, excels at culinary decoration using sauces, and favors mathematics academically.

His futsal journey began alongside friend Nozomi Komori. Kyōsuke embraced the goalkeeper role after being inspired by the "guardian deity" concept, reflecting his desire to protect the team by blocking goals—a duty balancing his playful nature.

Key relationships shape his life: Nozomi Komori, his earliest futsal companion and team captain, shares a bond since junior high. He befriended Rio Hanamura at their high school entrance, initially mistaking Rio for a stylish Tokyo girl; they frequently shop together. Within the Momomi team, including Natsuki Sogo and Yukimaru Kurama, Kyōsuke playfully teases Nozomi's edgy persona. Peers affectionately call him "Ai-chan."

He owns a cat and has distinct food tastes—favoring sukiyaki and udon while disliking rare meat and monjayaki. His comfortable family background supports his shopping interests.