[Renojustin]

I would think that the way to defeat Empire is with an early-mid rush with a heavy magic focus. Just hit them hard with magic and don't stop until you bring them to their knees. But Flagellents, Swordsmen (11 atk, 12 defense, 11 morale base with sword, plate, and shield all for 12gp omg), super cheap knights, and Marksmen make a ring of pure faith and steel around anything you'd be assaulting, and even their PD is pretty fair. It'd be a tough nut to crack and a VERY fine line -- you'd need just the right mages with just the right spells or they could match you act for act with 1-magic casters and alteration/evocation.

But once that magic starts ramping up, look out, because even the kitchen sink is not sacred and it will be flung at you along with everything else. And they can survive very well with low income because of excellent cheap troops that are extremely hardy.