The Dark Keeper Key drops from one of six possible Dark Keepers which spawn after a party member looks at the portrait in the Black Vault anteroom. This key is needed to open the Dark Coffer in the Black Vault. Each Keeper spawns in a different location, which the portrait gives clues to.
Source[]
This item drops from:
- Dark Keeper Bethek in the Black Vault
- Dark Keeper Pelver in the Domicile
- Dark Keeper Zimrel on a bench above the arena
- Dark Keeper Uggel in the Hall of Crafting
- Dark Keeper Ofgut in the West Garrison (at General Angerforge's location)
- Dark Keeper Vorfalk in the Grim Guzzler