Kozue Tsuzuki is a female schoolmate of the protagonist, Ryunosuke, though she is two years younger and not in his class. She resides in the same town. Within the dating simulation scenario, Kozue presents a potential romance option Ryunosuke can pursue during his final school year's winter vacation. Their developing relationship unfolds through meetings and conversations in various locations around town, following the game's narrative structure. She is one of several characters available for romantic engagement, including classmates, townspeople, and other local acquaintances.