The Upland Marsh is a large valley bog, with a collection of murky islands, rocky outcroppings, and groves of cypress and blackthorn trees standing out of the dead plant material and black water. Several of the islands are the ruins of ancient cities and buildings. A maze of drainage channels crisscross the marsh, like a fine network of scars. Dead corpses animated by the evil magic of Delecti the Necromancer haunt the bog; some are little more than skeletons, the black bog water has preserved others with hair, organs, and skin intact despite the passage of centuries.
In 1380 the Lismelder and Colymar tribes attempted to seize the rich farmlands along the under-populated stretch of The Stream which is called Duck Vale. The only occupants were various Unknown, especially the humanoid Unknown. The attack was successful.
However, three years later came an invasion from the nearby Upland Marsh of walking corpses. Some were very old. The Lismelder tribe called together its warriors and militia, but they were tricked and defeated in battle. The undead began burning all their houses and fields. An expedition led by a famous warrior went into the marsh. He was Kurash Varn, of the Sambari tribe. But he was ambushed by ducks, and the undead things just kept coming out. Divination revealed that the ducks were necessary to suppress the undead from the marsh.
At last a treaty was made, and the Colymar abandoned all the parts of Duck Vale which they had gone to, and paid compensation to the families of the dead.