The duergar are named after the dvergar of Norse mythology, who were the builders of Gleipnir.
The duergar first appeared in the first edition in the original Monster Manual II (1983). The duergar appeared as a player character race in the original Unearthed Arcana (1985).
There is an excellent Ecology article on the Duergar in Dragon #325.
As of 5th edition, and unknown to the Duergar, their god has been killed, and his role taken up, secretly, by Asmodeus.

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