I'm personally super interested in a unit of 40 flagellants with Warding Brand cast on them. Charge them up the board, they deal mortals when they die, mortals when they run away, are decent on the charge (especially with Ignite Weapons on them, taking the mto 4+/2+/-/1), and take up plenty of board real estate, all for the low low price of 280 points. A couple of those units sent in one after the other will wreak havoc (although they are shut down pretty hard by shooting).