Ur-gold is the name the Fyreslayers give to the magical metal in which they believe resides the dispersed essence of their god Grimnir. This Duardin deity was shattered during the Age of Myth in his fight against Vulcatrix, and since then his worshippers search for ur-gold across the Mortal Realms - fighting either against those who have stolen it, or for those who promise to pay them with it. Another way of obtaining this precious, godly material seems to be through recycling the corpses of deceased Auric Runefathers
The Auric Runemaster of each lodge is able to smelt and mold
this metal into magic runes, which are then applied by the Auric Runesmiters to the skin of the Fyreslayers to instill the energy of their god into them in battle.