Upland Marsh is about 35 km long and about 25 km wide. It is a high elevation wetland, with about a dozen small hillocks or islands that rise above the sedges and rushes. Several of these are actually the ruins of EWF settlements.
In the waters are hundreds, perhaps thousands, of corpses, preserved like bog bodies I suspect. They can be animated by the will of the powerful Vivamort demigod Delecti the Necromancer. Delecti is served by a cult of vampires who also aid their master by obtaining new corpses for him to animate (a big issue since 1613).
Trespassers are killed – except the ducks, who somehow escape Delecti’s notice or concern.
Delecti largely ignores the living that surround his domain. He can be persuaded to animate the dead on the behalf of others, although that requires his would-be employers provide him with corpses.
The Upland Marsh is also haunted by a much larger than normal number of ghosts and other malevolent spirits, no doubt summoned here by Delecti’s activities.
As an aside the Marsh is about as large as the whole city of Berlin, so plenty of room to explore!
I find the idea of bog body zombies far creepier than the usual walking dead. And they certainly would look weirder!
Are there any Slorflings/Red Elves in the marsh? No