(I can picture a haunted gold mine, but a haunted cow pasture? C'mon)
"It was on the second day without food. We'd been passing plants I thought edible, but our guide examined each and signed that we should avoid it - that we would have better soon. Of course none of us could really trust it... him, but we knew better than to ignore his warnings.
Soon enough the blighted forest ended and we came upon a wide expanse covered not with grass or brush but instead some sort of brown moss. Oh, and it stank. Indicating that the others should stay behind, the guide led me out from the trees and onto the moss. The earth felt oddly soft, but not remarkably so, given the circumstances. About six yards from the forest we stopped and the guide pointed to my knife and mimed what I soon realized was cutting a small piece of sod. When I asked why he pointed to his stomach, well, where his stomach should be. Peat, I guessed, for a fire. So, anyway, I shrugged, knelt, and started cutting.
After being in the Haunted Lands for a month I didn't even pause when the ground started bleeding, though I was surprised with the way it steamed. However, I did stop when the sound came. A low moan or rumble, it seemed to come out of the earth itself. The guide tapped me on the shoulder and clacked - I was to hurry. I set to and lifted a chunk of bloody meat from the... not the earth, from the other flesh. The guide ran and I ran after him. We'd not been back into the forest for half a minute when the great mass flexed and roiled, and the stink became unbearable.
We all fled deeper into the forest. The guild pointed out a fallen tree. We piled some kindling under it, put our hands over our ears and Aeris set the whole alight. After it'd stopped screaming we roast my "peat" and ate. I was hungry, but even without that sauce I think it would have been the finest pork I've ever tasted. At least I assume it was pork."
why not have Scions cities capable of generating big swaths of haunted lands around themselves by some method or other?
Two reasons. Both of questionable validity, but reasons none the less:
1) I don't know how.
2) Because other civs/religions have functions that automatically generate terrain. All other things being equal - or not terribly unequal - I'd like to have Scions do things differently.
Though you didn't say "automatically." A ritual might be nice.