Tactics for Necropolis.

Marmot, and vampires (although, unfortunately, it's easier to gather them than to prevent them from gathering). As for the undead, their immunities are both a plus and a minus (mostly a plus) - as far as I remember, not all enhancements work on them. And the neutral morale... There are no skipped turns, but there are also no extra turns (although lowering the morale of living opponents with dragons is quite pleasant).