My theory about Gronn, and ogres in general, is that the were once all like the Ogre Lords. The Gronn were giants of this kind, noble and shamanistic. Gruul was the greatest and most powerful of the Gronn. They taught the wild orcs the ways of the shaman, and built up a proud culture in the Blade's Edge Mountains and northern Nagrand. The ogres watched the orcs' civilization grow and were content. When the orcs were corrupted, the ogres attempted to stop them, but like the draenei, the ogres were corrupted, only much more terribly. Their people were left ugly, dumb, and vicious. The Gronn, so intune with the elements as they were, were left reddened, mad, and vengeful. Even the noble Gruul was corrupted beyond recognition. Only a few ogres escaped the full corruption. These rallied the ogres as best they could. They were the ogres' lords. Even they, left vengful and fearful of outsiders, became lost in fear and doubt as their world fell into chaos. Those Gronn of lesser power and will were left mindless, little more than beasts. They are the mountain Gronn. Gruul now sits brooding, trying to bring his corrupted thoughts back into sequence. The ogres became unrecognizable.