Judge is Campbell’s service dog, specifically a German Shepherd. For much of the novel, Campbell refuses to tell anyone Judge’s specific purpose, but after Campbell has a seizure in court, it’s revealed that Judge is a seizure dog. Judge can sense when Campbell is going to have a seizure about 20 minutes in advance and, when Campbell seizes, is trained to assist him in order to prevent any injuries. Judge goes with Campbell everywhere; any time he gets agitated, it’s a clue that Campbell is close to having a seizure.