As your men take some respite from the battle, they are quickly interrupted by vile, unnatural sounds coming from the vermin's lifeless bodies. Skeletal figures start emerging from the fallen enemies, the sound of ripping flesh and crackling bones is even more nauseating than the putrid smell.
By the time your men are back in formation, there already is an army of unholy risen creatures before them, joined by those who caused their return.
You send your army to scout the surroundings to make sure no more surprises happen tonight. Once satisfied, you head back to town to reassure the townsfolk.