Originally Posted by
Eiserne Drossel
Garrosh has been kidnapped and replaced by a Dreadlord who took his shape since they left Northrend. That's why he allows summoning of demons and whatnot on Pandaria.
We will figure it out at the end of the expansion when we will fight the Dreadlord who took the form of Garrosh, and be told that the real Garrosh is still alive, but taken somewhere else, and something bad is about to happen to him, they are going to inject demon blood into him! And that my friends, is where the new expansion starts with the invasion of the Burning Legion again, that Wrathion shows in his visions.
*Tinfoilhat*