Gray Dwarf (Duergar) (5e Subrace)
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The dwarf subrace, gray dwarf (or duergar), is copyright Wizards of the Coast. It can be found on page 104 of the Sword Coast Adventurer's Guide and page 81 of Mordenkainen's Tome of Foes. Between the duergar's two appearances, Mordenkainen's Tome of Foes includes more lore regarding the subrace, but the traits are identical in both books.