A hellhound is a supernatural dog, found in mythology, folklore and fiction. Like the dragon, many ominous or hellish supernatural dogs are found in mythology around the world.
They often have to guard the entrances to the world of the dead, such as graveyards and burial grounds, or do other things related to the afterlife or the supernatural. These might be hunting down lost souls or guarding a supernatural treasure. In European legends, seeing a hellhound or hearing it howl may be either an omen or a cause of a soon death.