Wind of Death useful?

[Loren]

A while back I used this spell to considerable effect. I was playing against the AI and decided to try something. I was being seiged by an army of about 1100 units. I had enough food from kettles and they couldn't hurt my walls but I probably would have lost in open combat.

My pretender could throw the spell with ease. I put Armor of Virtue on him, put him at the back of the battlefield and scripted him to cast it a couple of times and then retreat. I repeated this attack more than once. The armor got me out a couple of times and a couple more times I retreated. I whittled that army down to a couple of hundred units but for some reason I couldn't do anything more to them.