Necromancy in this mission will raise just over 10 ghouls, and on hard difficulty, vampirism is useless; the inquisitors' crossbowmen will take them down before you can even attack. And the Soul Eater isn't very useful either; by the way, it seems to be on the Path of Might, but Anastasia looks much better as a mage. In my opinion, the best weapon for her is Oblivion; we'll level up Restoration or Reinforcement to reduce losses. The tactic is to use Oblivion on the archers, and all enemies will be unable to shoot; then send the ghosts with Restoration/Reinforcement into battle. But that's how I played it. It's quite possible that there are alternative options.