The Dragonspear Vault Key opens the central chamber's westernmost door in Dragonspear Castle Basement. The key can be obtained from Caelar Argent's body. If the key is not picked up by the party, Aun Argent will give it to Gorion's Ward in a dialogue.
Description[]
| “ | An elaborately wrought key matching in many ways the sinister design of the Dragonspear Castle vault containing the portal to Avernus, this key was found on a golden chain hanging from the neck of Caelar Argent. | ” |