The Great Herrmann (played with pizzazz and panache by Fred Willard) was the stage name of magician Herman Gunt, headliner for the Conjurer's Castle. He was killed when the trap door of his stage illusion "Cementia!" failed to work. He was covered and suffocated in cement.
Before this, he had been a long-term father figure to Maurice and Ralston after their father mysteriously and literally disappeared in a disappearing act performed by Herrmann. Maurice and Ralston began to view Herrmann as a surrogate father, and regularly attended his shows. Because of this, the magician cautioned their half-brother Ned to avoid their clingy nature. Despite this, he would help the twins develop as magicians, and was grooming them to replace him. This upset both his assistant, Alexandria, and another magician he mentored, The Geek.
During a performance, Herrmann contacted Emerson Cod in the audience and asked for his help. Backstage, Herrmann reveals that all of his animal assistants have died recently, and worried he would be next. Herrmann died during his subsequent performance.
He was briefly revived, after his face was chiseled out of the cement, by Ned. Herrmann revealed that the magnets in his shoes, which activated the trap door for Cementia, must have been stolen. This tip led the investigators to accuse The Geek, who had the magnets in his stomach. Before being touched a second time by Ned, Herrmann asked for his magic book to be given to the twins.
He appeared in "Oh Oh Oh...It's Magic".