[Graeme Dice]

Originally posted by alexti:
Flames from the sky work nicely. Triple-casting it will reduce the army to about 1/8 of its original size. If they're hiding behind domes, flamestorm works nice too. Mass-wither-bones is another good strategy.

In my experience, triple or quadruple casting flames from the sky will only kill 1/2 of the troops at most, since the half that are outside of the camp are outside of the camp for every casting of the army killing rituals.