Are in my mind the closest good equivalent to a lich. It is pretty rare (in the history of CF, I've no idea of the moment) that you have to face two at once.

And of course the other question is would you want to go up against those same two paladins if one had defiance and the other was wielding spirit breaker or humansunder? I don't see how getting rid of one defiance makes that big a difference in the grander scheme of things.