The Underground Corpse Pile is, true to its name, a giant chamber containing countless corpses piled into mounds, there are so many of them in fact to the point that the blood flows like a small river and goes through the entirety of the Hunter's Nightmare.
More importantly, it is the lair of the crazed beast Ludwig, who has lost his mind and succumbed to the scourge by his thirst for blood during the Hunt, as have so many other Hunters before him.
- There is an "Undead Man" who speaks to the player as he comes in, bringing warnings of Ludwig. It is possible for this man to survive the battle between the both. He can be interacted with, yet he will simply laugh.
- Up the small staircase of the chamber, near the corpse mounds, there are 3 Blood Vials hidden off into the right side.
- It seems that the corpse pile was caused by Ludwig, which in turn, led to the river of blood that is seen throughout the Hunter's Nightmare.