Kuldotha, wellspring of molten metal, temple of the goblin horde, is a forgelike city sacred to Mirran goblins and Vulshok.
Goblins and Vulshok celebrate the power of the red sun at Kuldotha, the Great Furnace, which encloses the red lacuna.
The Great Furnace's blessing is a spectacular sight, but the best view comes at a high cost.
Once the Phyrexian conquest occurs, Kuldotha becomes fully Phyrexianized. It serves both as the main access point for Urabrask's Phyrexians to reach the surface and as the main conduit of molten iron from the surface to the Furnace Layer below. As expected, squealstokes run amok here, and the whole structure is filled with vaporized oil and smoke at all times.
The unexpected development at Kuldotha is that the structure itself has begun to demonstrate biological traits, likely as a result of the Spore bound up in the metal it melts down. It already had a sort of digestive system, and as time passes it seems to have moods and tempers as well. Too many impurities sicken it, and a steady supply of rich, pure ore and metal keep it quiet. How this quasi-alive state will evolve is anyone's guess.