Herr Wilhelm Diamant is in charge of supplying Castle Heterodyne with both new prisoners and their supplies. He reports to Baron Klaus Wulfenbach on the activities of his job. His official vehicle is a curiously-constructed prisoner transport van, badged with both the Heterodyne trilobite and the Wulfenbach winged tower on a field of per chevron inverted gules and azure. He later shows Agatha through some of the Castle's intricate passages up to the outer walls before forging her papers condemning her to Castle imprisonment and transporting her to the front doors.