For many ages, the mogu used flesh as a weapon: Warped, bent, and twisted to their malevolent will. But after their failures in creating the saurok race, the mogu sought to create another weapon... this time forged with total obedience.
Their ancient research delivered to them methods of turning flesh to stone, and back again. Lifeless rock could be animated, providing a willing (or unwilling) soul could be captured within.
These dark rituals created the Stoneborn, soldiers of jade and dark magic forged from the living essence of conquered victims. These creations were powerful... terrible to behold, and above all else, one hundred percent loyal to their mogu masters.
Let's get some gnomes and dwarves up in here too.