[MaxWilson]

Drain Life always hits, is impossible to resist, and comes on a D4 item. You won't gain any fatigue back from the Bane Lord, but item-casting is cheap anyway. The tactical AI is pretty good about casting Drain Life only on tough enemy units, so you should pick him out of a horde of chaff pretty quickly. Depending upon what "fully decked-out" means, the specific anti-undead counters (Inner Sun, Just Man's Cross, Solar Rays) may be more cost-effective, but Drain Life items are useful to have lying around anyway and AFAIK there's no way to counter them except killing the casters.

-Max