The real danger had arrived, the ghosts.
The bats though flying monsters with fairly fierce claws and fangs paled in comparison to the threat generated by the horde of ghost monsters. Frost's forces were unfortunately poorly equipment against such enemies.
The physical attackers fled desperately on the frost troll lieutenant's order but not all were quick enough, just like the unfortune ice dwarf a fair few were caught by the ghosts ethereal weapons or even by their very hands.
Eerily their fog like bodies would slip through their armour and skin, attacking their very souls, snuffing out their life force yet barely leaving a mark. If the heart and or major organs were avoided the victim may very well survive but the damage would be extensive and regular healing spells and low level potion struggled to heal such injuries given their cursed nature.