Male. A friend of Guest who exudes a cool atmosphere, but knows nothing about mahjong rules. He has a bad habit of remaining silent whenever he doesn't understand something until someone else provides an answer. He is incredibly soft on his younger sister, Aoi, and will accept whatever nonsense she says with a simple "If Aoi says so, it must be true." Most of the time, Akane's internal thoughts are actually correct, but he never voices them.

Female. Akane's twin sister who possesses a somewhat aloof aura; she knows nothing about mahjong rules. She has a bad habit of making up plausible-sounding lies whenever she's confused. She is actually quite intelligent, but because she has a cynical view of society, she figures she can just nonchalantly correct herself later if she's wrong. That said, she values her friendships and never looks down on others.

Female. A 13-year-old child prodigy who skipped grades to study abroad; she knows nothing about mahjong rules. She has a bad habit of acting without thinking whenever she encounters something she doesn't understand. Her high level of initiative is a virtue and she often breaks deadlocks in the situation, though this also frequently causes the conversation to spiral in bizarre directions.