Soul grinders are a type of engines used by the Scourge in the Forge of Souls. The Alliance and Horde attacked the Forge in order to destroy these twisted machines.
Bronjahm was the foreman of the soul grinder engines. After learning from Kel'Thuzad himself the value of souls and how to grind them down to fuel the engines of the Scourge. He patrolled the Forge to ensure that no interruptions befell the engines' operation.
The Devourer of Souls was the chief operator of the soul grinders, dedicated to preventing souls from escaping the dark machines. It would consume stray spirits and break them down.
- Sleeping flesh giants can be seen in the background of the Forge of Souls, implying the souls are used up to power them.
- Although they are the primary set piece for the dungeon, especially Bronjahm's fight, they are not directly interacted with or mentioned in dialogue.