Kozue Satonaka appears in the visual novel "Kita e. White Illumination" as one of eight female characters the protagonist meets during his summer trip to Hokkaido. She is a 17-year-old high school student from an affluent background, displaying interests in cosplay, video games, and frequent email communication. Initially characterized by a spoiled upbringing, she exhibits expectations of having her desires readily fulfilled.

Her personal storyline involves financial struggles at her family's restaurant due to harassment by local troublemakers. This crisis leads her to seek the protagonist's aid in developing new recipes and promotional strategies to revive the business. A distinctive detail includes her wearing an eyepatch during early encounters, though the reason remains unspecified.

Kozue's narrative centers on evolving from self-centered tendencies to actively collaborating on her family's challenges. This joint effort signifies her growth beyond initial entitlement, marking a pivotal transition in her character arc.