Demons are a fictional species featured in The Thief and the Cobbler.
Zigzag, a sorcerer of rather low power, claimed to be able to "conjured demons". He demonstrated this my materializing a dragon-like creature out of thin air with a wave of his hands. The small dragon then bit its tail at Zigzag's command and breathed fire, turning itself into a burning hoop. Whether this is the appearance of all dragons, or merely of one out of a wide variety, is unknown.