Mortal Shell 2 Blackmarrow Key

Take a Blackmarrow Key back to the hub secret-room route after opening the breakable-wall passage and shooting its four chains. Community walkthroughs associate the room with hidden Shade rewards. ^[community]

Do not confuse this key with the Chapel or Crypt Key. If the interaction does not appear, re-check the chain mechanism and current patch before assuming the key was consumed incorrectly.