Kousuke Tamiya, a college student, spots Chako Hasegawa at a cosplay convention and instantly declares himself her first and most enthusiastic fan. His passion lies in photography and observing cosplayers, his camera an ever-present companion on outings.

He forms a connection with Chako, who develops romantic feelings for him. Largely unaware of her affection, he often mistakes their meetings for photography sessions rather than dates. His friendly and charming nature inadvertently deepens Chako's emotional attachment through this obliviousness.

While on a photography trip during the East Oizumi Cosplay Club's beach training camp, he unexpectedly crosses paths with Chako again. He expresses anticipation at seeing her participate in the upcoming River Ceremony festival.

Beyond photography, he demonstrates talent as a skilled artist with drawing abilities. No significant character development or expanded background beyond these interactions is depicted.