The Warden Vault side quest in Dragon Age Veilguard tasks you with opening three locks using puzzles
Opening the Dragon Age Warden vault requires you to venture throughout the Warden Castle in Rivain, solving three different puzzles to open three locks. It's a simple quest on paper, but you need to be thorough in your exploration of the castle as the puzzles are quite well hidden, and one of these Dragon Age The Veilguard puzzles isn't even particularly clear. To help you crack the locks as painlessly as possible, I've explained the entire process for unlocking the Warden vault in Dragon Age Veilguard and completing the relevant quest.
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.
You'll find the vault under the floor of the main hall at the entrance to the castle. Descend the steps on the west side of the hall, burn down the obstructing drakestone, then carry on to find the sealed doors, which should be unsealed if you've completed the following lock puzzles.
The first of the three Warden Vault locks is quite well disguised in a hidden part of the castle, but thankfully the puzzle isn't that difficult to figure out:
The second Warden vault puzzle is a little further into the castle and has you running all over the place chasing a green spirit around - use the map above to help you navigate. As you move through the castle, you should wander past a skeleton impaled with a sword surrounded by ghostly, green butterflies which is where this puzzle begins:
The third and final lock is all the way at the end of the castle path at the very start of the Castle Bailey area and it requires you to guide a wisp to the right spot in time:
The Grey Warden vault in Rivain is a treasure trove containing all sorts of useful items. Some of the rewards are random and change based on which of the Dragon Age Veilguard classes you've chosen, but there are some consistent items across playthroughs. Here's what you can expect both inside the vault's chests and for completing the relevant quest itself: