Kozue has been Kū's best friend since they were little and always keeps her in mind. She has her energy drained from her by Tarlotte during one of the latter's attacks on the school Kozue attends along with Kū. She has a fascination with Jin Ōgami. She remains concerned with Kū's well-being after the latter disappears and tries to contact her, though Kū is unaware of this and believes her place at Kozue's side has been taken. Neither of Kozue's parents are with her. She appears to resemble Makoto from Kannazuki no Miko