"By this blood I swear my soul and heart to the blackness and to the Iron Scourge"
-from the oath of the Iron Scourge fraternity
Iniquity is a world of huge mountains rising from an acid sea, orbited by a fractured moon. In warrens burrowed into the dark rock of the mountain lurk thousands of renegades and scum of the worst kind. It is a world that exists to feed its feral packs of Chaos raiders with metal and supplies, who return with captured prisoners to toil in the foundries and poisoned mines. There is no lore on Iniquity save the lore of might and murder, and its brutal society is split into fraternities bonded by blood and pledges made in unholy tongues. These fraternities control the mining and smelters in the deep reaches beneath the mountains and watch over the toiling armies of captives whose lives are best if they are short.
Long ago mines were established on Iniquity, burrowing into the mineral-rich rock despite thousands of lives lost to rock falls and poisoned gas pockets. That time was ended when the indentured workforce rose up and slaughtered the mine overseers and daubed the dark walls of the mine workings with their blood. Some attempt may have been made by the backers of the mining operation to regain control of Iniquity, but if there was, it remains unrecorded, and its failure is obvious from the evil tales that seep like a blood stain through rumour and whispers even to Port Wander. To this day none has ever succeeded in cleansing Iniquity- Though many have tried and failed to return.
~(From Rogue Trader)