Citing from an earlier reference, that grand folklorist Katherine Briggs ("A Dictionary of Fairies," 1976) describes Duergars as "the worst and most malicious order of fairies"; being "black dwarves of the north of England, always full of malice and the enemies of mankind." (a bit like Yanks in Iraq then!) A tale is told of them in F. Grice's "Folk Tales of the North Country" (1944), pp.130-33...