He really, really was. Combined with his flying he simply appeared infront of the enemy army, let off a few spells and then after the first few enemies died from his fireshield they routed due to his huge fear AoE.
You did check the morale of your enemies, right? I'd quess even things like blessed Knights of the Chalice would have their morale at 4 or 5, and normal infantry might have -3 or so...
I wonder what would happen if i combined him with a few scorpion men (is it possible to reduce berserked/other extremely high morale units down to a routable level?)