fleeing sc?

[Nick_K]

At high difficulty levels the AI get lots of extra cash so they'll often field very large armies regardless of faction. I've had a difficult (not impossible) AI on the 'eye' map throw 1000+ armies for about a dozen consecutive turns at a chokepoint fairly far from my main recruitment areas, while still carrying on the war on other fronts.

If the problem is with the ashen empire in particular then there are more effective ways of beating the hordes than by using SCs. And, as you say, life-draining will not be effective (soul vortex should still deal the same damage, but with no life or fatigue benefit for the SC it's not really worth it).