Having failed to create an obedient army with the saurok, the mogu devised other ways to create the "perfect" fighting force. Using dark magics of unknown origin, they captured living souls and imprisoned them within constructs of stone.
Over the course of several dynasties, a vast army of these living statues was constructed and housed within an enormous vault carved into the mountains of Kun-Lai.
Knowing that this secret weapon would be their downfall, pandaren monks attempted to seize control of the vaults immediately after the revolution began. They struck quickly, ambushing the mogu by rappelling down the mountain from the Peak of Serenity. The battle for the vaults lasted four days before a snowstorm forced the mogu from the mountain.
By depriving the mogu of their secret weapon, the rebellious slaves forced the mogu to fight on more balanced terms.