Looks like it would open a very old lock.
— In-game description
Dwarven Keys can be used to open various small tombs in Dredgehaunt Cliffs and have no use outside of that map. When used they will trigger an event to kill a veteran foe, after which a treasure chest will spawn for event participants. The known doors and the events which begin are:
- In a cave north of Grey Road Waypoint, at the Tomb of Stoneskin POI. (Near the collector Oliver. Starts the Kill the imp lord to stop him from summoning more imps event.
- North of Tribulation Waypoint, at the Tomb of Blackpowder POI. Starts the Slay the destroyer troll released from the tomb event.
If an event has ended recently, the doors to the tomb will appear open, when they are actually closed. There will be an invisible wall blocking your way and there will be no prompt to open the door. You can still start (or reset) the event by using the Dwarven Key from your inventory, but you will not have to kill the boss to loot the chest.
- Random drop from foes in Dredgehaunt Cliffs