Beauregard is a demon from Xanth. He was first introduced in A Spell for Chameleon.
Beauregard is a friend of Humfrey who uses him on occasion to help answer questions. He is highly educated and writing his doctoral thesis: "Fallibilities of Other Intelligent Life in Xanth". He is moderately demonic-looking but his horns are vestigial and his tail is tufted not barbed.
Novels: A Spell for Chameleon, The Source of Magic, Centaur Aisle, Ogre, Ogre, Question Quest, Air Apparent