unless you take fire on the pretender then you need randoms/empowerment. The charcoal shield can be used by mounted troops and only use it on melee units as all it does is grant a strength 7 or so fireshield (so anyone who hits you takes 7 armour piercing fire dmg, deadly vrs un dead. Also remember that a f9 or so pretender gets around 15ap fireshield...)
Doesn't Machaka get Death/Fire mages? That gets you Skulls of Fire. Of course, it's Construction 6, but might still be easier than empowering. And then you can make Flaming Helmets, though I'd rather use the Skulls in battle, since the helmet has extra fatigue.