A Warrior hero from the Dungeon faction? That's absurd...

I wrote my post in the "Leveling up Tier 5 units in the late game" thread and attached replays there. I played against myself, but it provides some visual clarity. The conclusion is that in the late game, it is quite possible to either use a "kif" spell as mentioned above (instead of Chaos, you can also use Summoning) or, even more effectively, use Elemental Fury and, if you're lucky, Rune Power. Try to level up defense as much as possible, and as a huge bonus, cast Chaos. For example, an explosion with 2k damage, combined with Elemental Fury, Rune Power, and Luck, will deal almost 13k damage, which is like 130 champions per cast. And the counterspell is actually useless; you cast it with your warrior-caster, remove the counter, and then cast it yourself, plus with Sorcery, you can cast it again, while your opponent just wastes their turns.