New units in Necropolis. Discussion and selection between upgrades.

You can simply protect your archers with your own troops (as I do) so that there is nowhere for the poltergeists to stand and attack. I usually place archers next to unicorns to deflect dark magic, and in front of the archers, I place dryads or wind dancers, and all of this is placed right at the edge of the battlefield. And I always have a cart with me.