[Nick_K]

The unquenched sword won't actually kill an enemy army. Against flaming arrows you'll probably still die. Woundflame is great, darkness or storm should also work although you need the mage & gems.

The robe of invulnerability can be good if he has a big forge bonus. I was pumping them out with my EA ulm pretender (no innate forge bonus) using 'forge of the ancients' and the 'hammer of the forge lord'.
The shield of valour (earth/air) gives air shield which will stop most missiles. You can also get air shield from a misc slot (amulet of missile protection) or from the silver hauberk armour.
Flight might help against archers, but off the top of my head I don't know what the best items for it are.