Dung Eater will invade you mid-way through his questline or at the end of Blackguard Big Boggart 's questline. As you get a Seedbed Curse, head to the Roundtable Hold and show it to Dung Eater.

This rune will allow you to access an alternate ending in the game's finale. Loathsome rune gestated by the Dung Eater. Used to restore the fractured Elden Ring when brandished by the Elden Lord.