The Tender of the Forge, as Tharmekhûl is also known, is Moradin's
assistant. He is the deity of furnaces and fire. Usually smiths and
other dwarves who revere the creative power of the forge worship him.
However, fire has a destructive side, so Tharmekhûl is also revered as
a minor war deity, primarily concerned with siege engines and other
weapons. He is depicted in religious art as an Azer or as a
bronze-skinned dwarf with hair and beard made of black smoke.
Source: Races of Stone