Well, in the middle ages (for example at the battle of hastings) priests and monks fought with clubs (because they werent allowed to break the skin or cause bloodshed, and they thought they were being clever by using clubs instead) but the idea of them forming a 'unit' or having a line of priests charge the enemy is a bit ridiculous. Still, I think that given the dark depths of my expectations of BI, it might be surprisingly fun in a stupid sort of way.

I'll make an army of monks and charge them at a line of orager-chariots firing flaming bombs in the middle of the night.

It'll be crazy.