Goths or Sarmatians, depending on where their starting positions are!
First I'm going to stay at my starting position and take on the entire hunnic horde by myself, and then, when Attilla and his men are all dead or at least have surrendered and become my protectorate, I'll create 3 full stacks and move them towards Adrianople and from there on to Rome, killing all roman armies I meet on the way and replacing my casualties with mercenaries. I'll not conquer a single city on the way (at least not more than 2 or 3), but I'll conquer Rome, and exterminate the city, tear down every building in the city, and then move my armies on towards the Iberian peninsula, where I'll settle down and create a new empire. Then I'll try to conquer all settlements between the new empire and my starting position where I still have troops and settlements left.
My second campaign will be probably be as the east roman empire or the sassanids. It's been a while since I last got to use cataphracts... Of course, I'll not allow myself to create a single army with more than 4 cataphracts in it. The rest will all be infantry... I'll first conquer the entire Middle east and Asia minor area, then I'll send some full stack armies around on expeditions. One will conquer all North african and Spanish cities and tear down all buildings, then leaving the cities to revolt. A second one will do the same thing in the Balkans and the Italian peninsula, and a third one will go to Britain doing the same thing.
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