The ruined towns and cities of the Worldwound were once Sarkorian settlements, with the notable exception of the lost crusader citadel of Drezen, a sad reminder of the overconfidence of the First Crusade. Countless thousands were lost in its fall, many overwhelmed in a wave of sheer chaos and perverted into hideous chaos – beastmen who turned on their fellows in a cannibalistic frenzy. Those who did not survive were taken from the city and nailed to the Crown of the World, their anguished spirits distilled as “white wraiths” capable of freezing a man to his marrow at a touch. The crusader shrines within the city were horribly perverted to cultic demon-altars, but much of the city remains intact or is even rebuilt. The marilith mistress of the city, Zuhra Aponavicius, is one of the most aggressive of the demon commanders, ready to sacrifice minions by the thousands as long as she can bloody the enemy.
Sources: Pathfinder Chronicles Campaign Setting