Kyouko Hazuki (葉月 杏子) is a woman with brown hair and brown eyes who owns and operates Cafe Moon World, positioning her as a central presence in its daily life. Her background is marked by widowhood after losing her husband young, an event that deeply influences her worldview and interactions.

She shares established ties with Reiji Tokisaka and Kyozo Uozumi, both former police officers and regular patrons at her cafe, their connections rooted in shared service on the force. Kyouko voices concern over Uozumi's habit of involving Reiji—now a private investigator—in active cases, fearing the risks this poses to Reiji's safety.

A deeper bond links Kyouko and Reiji through shared trauma: each endured profound loss, with Kyouko mourning her husband and Reiji grieving his murdered fiancée Yukiko, whom Kyouko knew as a friend. This mutual understanding of grief fosters a unique sympathy between them. Though attracted to Reiji and agreeing to offer each other companionship against loneliness, Kyouko avoids pursuing a formal commitment.

At her cafe, she engages with other characters like the student regular Toko Kuchiki, often facilitating pivotal conversations and narrative developments through the space she provides.