Halberds are for charging vs certain enemies. They have ap-2 on the charge, and as I’m strapped for pts they do end up costing 20 pts less than a great weapon. If I had 20 free pts I’d use GW - which I’ve decided to use on the regular infernal guard instead of the blunderbusses i think, the blunders are fine but not worth 5 pts unfortunately.
So the ironsworn are anti infantry and the guards are anti monster (with the no stomp banner)
