The bell tolls, and an indicator appears: the nightmares are coming from the south.
I’ve been aggressively fortifying new expansions, anticipating that the enemy’s next wave will come from somewhere they’ve not previously struck. Now, it seems, they will be poised to attack along two possible paths. One route leads north and east, winding through the unexplored darkness to emerge near a new iron mine, beside a new line of my strongest walls and towers. The towers are each manned by an arbalest and a trio of archers, and nearby stands a large ballista.
The second route goes north and west, this time emerging by a very narrow path through a forest that leads into an area of farmland, and also the previous walls the nightmare horde attacked. The narrow passage is protected by a single tower and a few layers of walls. The more fortified area only has two archer towers, albeit behind two rows of solid walls.
This will be tough. They could strike at any of these three locations. Each is protected to varying degrees, though neither will hold against the numbers I expect. So I add ballistae and more towers for arbalests and archers at each location, and throw up outer lines of staggered low-quality walls. Thanks to a boon earned from surviving a previous nightmare assault, it’s more likely than not that any destroyed building will explode, damaging nearby foes. I move my melee army, lead by our mighty fire-wielding hero unit, into a position midway between the locations, and train more forces to man the new towers and bolster the ground support.
Behind these defences lie unprotected farmlands, resource gatherers and utility buildings. Behind those are incomplete walls of earlier eras, and those are all that stand between invaders and the Keep I must protect. The nightmares will make a beeline towards the Keep, moving like a single hungry swarm. Elsewhere my lands are protected by more solid second layers of defences, but not here. There is no time, and more pressingly there are no more resources, to deal with this problem. The nightmares are here.