It was a feature advertised, and would still be a cool thing. Finding a group of Undead gathering to attack a nearby town. Calling out to others to help kill the force before it attacks the town. Possibly defeating them before they attack. Or failing to stop them and they attack the town. Destroying part of it, which will need to be rebuilt. Or having to come back in and drive them out of the town.
Or
Undead attack a bridge that has been build. Defend it, if not it is destroyed.
Or
Undead attack houses in a town, destroying the house(s). Pain to rebuild but its all part of the game.
Or
Attacking a area of undead, killing 100s , the blight begins to roll back! just a little, but enough to show us that we CAN win this war. Would take a long time to push back all the blight , and about time we do. I'm sure you could have something else going on.