The Warden Vault is a side quest found in the Rivain Coast region in Dragon Age: The Veilguard. The quest consists of a few short puzzles that you need to solve in order to open the three locks that grant you access to the actual vault itself, which contains lots of useful rewards - including a unique-rarity ring.

The Veilguard's treasure-hunting quests, as you scour a ruined castle in the Rivain Coast region, looking for seals to unlock some loot. It's quite easy to miss if you haven't explored the region thoroughly,

To get into the vault, you’ve got to open three lock mechanisms around the Warden Castle area of the Rivain Coast. Once you’ve cracked each puzzle, a Grey Warden seal will be revealed which you need to activate, and when all three have been activated, you can get into the vault itself.