I was wondering where the heck all my mana keeps going and realized it was disappearing due to auto-resolving battles. I can understand that some mana will be used, but my army, with two champions in it, is using 200 to 300 mana to auto resolve a battle.
I've been playing on normal, so maybe I'll try a harder difficulty soon. However, even with recent balance patches, it seems too easy to become neigh invincible by using either your sovereign or champion as a tank and outfitting them with all the best items you acquire. Then, with another champion playing a support/caster role, there's not much of anything that can stop you. Here's a few of the issues I've seen that seem to contribute to the problem,