Chuuya is a member of the Port Mafia's Flags in charge of a gemstone black market. Aiding Adam in the investigation, he learns about his existence throughout the case and how he is connected to Verlaine.

As a robot, Adam's programming does not cover everything and he must occasionally update it, sometimes based on incorrect interpretations of the world. For example, when his plane crash lands in a forest, he simply decides Japanese airports are covered in trees, and later keeps swallowing gum.