Bui is a twenty-two-year-old male character who, like Ichiyo, is a poet. His defining personal trait is a fondness for gambling, which often leaves him in a state of financial trouble because he spends any money he acquires immediately. This pattern of behavior has led him to be constantly broke, and his desperation for funds has driven him to engage in actions that border on fraud.

In terms of his role and relationships, Bui has a past history with Kaka, whom he once attempted to obtain. This effort was met with harsh treatment from her. Following this experience, he became close to Ichiyo, though this closeness is one-sided as Ichiyo does not share the same feeling. No additional information is available regarding his background, overall motivations within the story, notable abilities, or any significant character development.