Like everything else in the wasteland, the religions there also suck.
Never go into a major battle without first considering a sacrifice...
Your raiders are an unruly and superstitious lot, perhaps offering some water or meat might appease the gods enough to inspire your army to fight a bit better. Sacrifice a bit of beer (sacrilege!) and they might take the offering even more seriously.
However, the option also exists to sacrifice captive workers or even...one of your own raiders, in order to further boost your followers fervor on the battlefield, successfully awakening their blood lust and violent nature. These sacrifices offer significant combat boosts that can make the difference in capturing that settlement you have your eye on.
As well, after battle, you will have a chance to loot either scripture pages which will amplify the duration of bonuses received after a sacrifice, or holy relics which will provide permanent boosts and modifiers to out-of-combat stats.
Hope you enjoy this update!
And remember: in the wasteland, do unto others before they do unto you.