You haven't seen the catapult yet!) Phoenixes are also dangerous; they resurrect three times, and the Devil can summon three Ice Elementals.
By the way, creatures that cast spells are enhanced by magic.
Disintegrate now costs 18 mana and deals 180% damage. Choke has been increased from 80% to 100%.

Although, if you think about it, everything is correct: the champion is the antithesis of the champion of darkness, and his damage compensates for the bonuses that the dark champion has.
I would also suggest these changes: +7 damage to Fiends, +6 to their attack and defense modifiers, and +10 HP to compensate for their weakness against vampires.
+45 HP and +35 to damage for Sea Serpents. I think they should be stronger.
Berserkers and Bulls should get a speed boost, and the Dragon King should actually be a king!)