Who are the Thorium Brotherhood

The Thorium Brotherhood are a splinter faction of the Dark Iron Dwarven clan. During the war of three hammers, the three major Dwarf clans (Wildhammer, Ironforge and Bronzebeard) had a war with the Dark Irons, under the rule of Than Thaurissian.

The Dark Iron Dwarves lost the war, and retreated to what is now Blackrock Mountain, where they were enslaved by Ragnaros. Some of them, escaping his grasp, turned on their evil ways and formed the Thorium Brotherhood.

These mercenary Dwarves and master Blacksmiths now cater to adventurers, offering several quests in Searing Gorge and Blackrock Mountain. One of them (Lothos Darkbargainer) currently hides in the tavern in Blackrock Depths, offering crafting secrets of the Brotherhood to those who have earned enough reputation with them.