Draft:Rampart Castle Vault
The Rampart Castle Vault is the time-locked treasury beneath Rampart Castle. Its concealed approach and alarmed treasure rooms are part of the city map, not a separate dungeon level.
Finding the treasury
Secret passages run beneath the castle, with a concealed approach from its moat. Searching is useful both for the entrance and along the passage: some tiles conceal traps as well as the route. The treasury contains piles of generated objects, rather than a fixed cash reward. Its inner treasure tiles include alarm traps that summon the attention of the city's law enforcement.
Crossing the moat also needs preparation. Body armor or a load above half your carrying capacity drags an unmounted character underwater. Breathing protection, levitation or a mount can help with ordinary water, but none of these should be confused with protection from the treasury's alarms.
The time lock
Visit the vault entrance during 23:00-23:59 to open the time lock without attempting to crack it. Outside that hour, using the vault closes its entrance and offers a cracking attempt. This is an entrance interaction, not a guarantee that a previously opened door closes automatically at midnight.
The chance to crack the lock is the square of your Thieves' Guild rank, as a percentage. A successful attempt awards 5,000 experience. Dexterity, a lock pick and a weapon are not part of this particular check. Failure invokes city justice, except that a reigning Duke is simply told to stop testing the lock.
Opening the lock does not disable the treasure-room alarms. Becoming Duke through the castle quests disables those alarms, but leaves random traps in the outer secret passages.
Strategy
The predictable 23rd-hour opening is preferable to gambling on a low thieves' rank. Leave time to reach the entrance, and search before advancing into the loot. Getting through the door is only one part of a robbery.
Shadowform is especially useful here: it permits passage through walls and bypasses the ordinary trap and vault interactions. Its duration still matters; being able to enter a dangerous area does not supply a return route after the effect expires. Becoming Duke provides a slower but more straightforward route to the alarmed treasure.
History
The older player spoiler collection describes approaching from the moat, searching along the passage, waiting for 11 p.m. and using Shadowform. Those leads agree with the corresponding 0.90.4 entrance and movement rules. Its sweeping claim that every treasury square has an alarm should not be extended to the entire castle or every secret passage.