Kozue is a schoolmate of Aiwa and exists primarily as the persistent object of his romantic and sexual fantasies. She constantly occupies his thoughts, embodying his idealized yet unattainable romantic goal. Her presence motivates Aiwa's actions and desires. Kozue functions as a direct contrast to Satomi, the android who unexpectedly enters Aiwa's life. While Satomi becomes physically present and available, Kozue remains distant and inaccessible throughout the story, creating tension between Aiwa's fantasy pursuit of her and his reality with Satomi.

Kozue eventually visits Aiwa's home, an event which creates urgent pressure for him to conceal Satomi's presence and true nature. This situation reinforces Kozue's role as an external complication rather than an actively developed character. No information exists regarding her family background, personality traits beyond Aiwa perceiving her as desirable, or character development. Her relationships with others beyond Aiwa's fixation are also unspecified. Her involvement is confined to being the unattainable romantic interest existing primarily in Aiwa's imagination, serving as a narrative device to create conflict with Satomi's arrival.

The character does not appear or develop in any spin-off media, additional seasons, or related productions. All information about Kozue stems from her limited role within the primary narrative, where she functions exclusively in relation to Aiwa's story.