The Duergar are a race of ugly dwarfs, particularly associated with the Simonside Hills of Northumberland, in northern England.

Described as being short, wearing a lambskin coat, moleskin trousers and shoes, and a hat made of moss stuck with a feather these beings delighted in luring travellers to their doom in bogs and marshes in a similiar fashion to the legendary Will O' The Wisp and appeared at night, disappearing at dawn.

Due to the Duergar's love of mischief and seemingly dislike of daylight they are likely part of the Unseelie Court, which is a collective term for evil spirits and fairies in British Folklore.