Ew immolation? Burn + Evasion, burn the dk he runs out of mana, that means no heal or nuke for him. Immolation, will drain your mana quickly and if your nme knows that you got burn+immo then they will certainly target you. Nuking doesnt have be used more than once.
No one will ever mass fiends btw without statues or destroyers, i hope atleast. Sticking straight to archers doesnt work against fiends, but if you do dotts and use cyclone, then that should be good enough. But if i was against that, then skeleton wand is the way to go + the crypt lord with impale with a mixture of ghouls.
And unarmored units in any case, just sucks, dont even bother getting them unless they have some certain role.