Uninvited guests.

While reviewing a saved game featuring a Necromancer, I noticed that Dexter doesn't have the "Raise Dead" spell. What's the reason for this exclusion? All standard Necromancer heroes know this spell from the start. Dexter can only maintain "Vampirism" on zombies. And another question: if he has "Eagle Eye," can Dexter learn "Vampirism" on himself?