With the new raids and us having to kill the Imperator, and me not being able to find any further inrmation about this Ogre Empire (not mention of such thing in any of the WoW archive novels) I would like to know when this creatures became an empire. It seems obvious they were in this new timeline an empire long before Garrosh arrived, but it was already falling? or started falling with the attacks of the Iron Horde? 
When did it come to be an empire when in our timeline they're no more than tribes of brutish creatures. Or were they an empire in our timeline, but one that was extinct long before the draenei arrived in Oshu'gun?

I would appreciate any answer! thank you!