[Endoperez]

If you can cast Ritual of Rebirth, the pretender will transform into an undead mage instead of dying. He won't lose 1 pick from all of his magic, but healing his afflictions will be much harder (you'd need The Chalice artifact, I think). If he gets something like Mute or Feeble-minded, that's it, but if he only gets stuff that doesn't affect his magic, he might get away.