Through a dark pact the Svartálfar sorcerer had learned the power to turn creatures to stone, just like the medusa, the basilisk, and the cockatrice. He used this power to enslave many peoples, and slowly built up his armies.
Some slaves have tried to escape his lands, but magical wards warned the Svartálfar and he uses The Dark Portal to appear in the path of any escapees. He could also return to The Dark Portal from anywhere. There was no escape, only the eternal punishment of stone. It was said that these were living statues...not dead, not dead.