Yes my first game was entirely Undead (2 types of ghosts + vapires and later necromancers). Ghosts are easily avaible, but vampires are much harder. Ancients ones will be 80% sure in dwarven land, by undead necromancer dwarf. The normal version... well they could be in castle on swamps, but not necesarilly. Best way is to rise them bu Sacrifice spell from the vampires in coffins on swamp. The're always there. Necromancers will be in Demonis or Death land.
Good luck
