Joseph is a minor character who appears in Emperor's Treasure. He works as a security guard.

Phantom R finds him sleeping on the job during his attempt to steal the Bracelet of Tiamat. By recording Joseph's snores, Phantom R is able to get into the security room, which is closed by a voice-recognition lock. Later, Phantom R also finds a notebook that apparently belongs to Joseph on the ground just inside the Denon Wing of The Louvre. It reminds the reader of the change to a password, instructing the user to press the button whose sound does not have a pair. Phantom R uses this information to open the case to the Bracelet of Tiamat.

He is also an accomplice in Rhythm Thief & the Paris Caper called "Constable Joseph C". He can be promoted to Constable Joseph B.