From MTG Wiki
Mirrodin. Vulshok barbarians live there, working their forges for trade. Goblins reside in the Chain as well. Kuldotha, the Great Furnace, lies on the inside of a gargantuan hollow mountain. Molten metal come from the bowels of Kuldotha, and it is the hallowed ground and home for the Cult of Krark, as well as the worshippers of the Steel Mother. The Red Lacuna was somewhere within the Oxidda Chain.