The Dung Eater is a vile NPC that wants nothing more than to defile your corpse. This depraved Tarnished first appears as an invasion spirit in Roundtable Hold, unable to do anything. You can find him in the room just past the Twin Maiden Husks, surrounded by piles of corpses that will make even the bravest of Tarnished feel uneasy. After obtaining one of the Seedbed Curses from a defiled corpse out in the Lands Between, the Dung Eater will tell you to find his body. Here is where you can find the Dung Eater’s body in Elden Ring.
The only clue that the Dung Eater gives you to help you find his body is that it is in the Sewer-Gaol below the Royal Capital. Of course, this isn’t much to go on, but it’s a start. You can find the Dung Eater’s body beneath the capital. After learning this, make your way to the Royal Capital and head to the giant dragon statue’s wing. Normally, you would use the wing to get up through the city. Instead, you will want to go beneath the dragon’s wing to the area covered in shadow. Here, you will find a well that you can climb down that will lead you to the beginning of the sewers and to the Subterranean Shunting Ground.
The first Site of Grace in the sewers is the Underground Roadside. From there, make a left out of the room that the Site of Grace is in and follow the pathway to an opening in a grate. This area is surrounded by Omen enemies so keep your guard up. You can easily sneak past them by crouching if needed. Drop into the sewer grate and follow the path to the end where the large Miranda Flowers are. You can run past them if you would like or fight them all.
After getting past the Miranda Flowers, climb the ladder. This will lead to a room with a locked cell that contains the Dung Eater’s body. Watch out for the fingercreepers on the ceiling and under the floor. You will first find his body beating its head against the wall of the cell endlessly. After completing the Dung Eater’s quest, you will find his body in the same cell but tied to a chair like one of his victims.