system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] What are the Dead Marshes? Why do they exist?
gpt
They're a swamp, nothing more. Over the years several battles were fought on or near them, and the slain either fell into the swamp or were buried nearby and drawn into the mire as the marshes expanded. The bodies, preserved by the peat, can still be seen beneath the water. Will-o-the-wisp tends to form near the bodies, tempting travelers to accidentally drown and become one more body in the muck.