Skyrim:Snow Veil Sanctum

It contains two zones, Snow Veil Catacombs and Snow Veil Sanctum. It is locked and inaccessible prior to the related quest Speaking With Silence, during which it is the hideout of Karliah, a supposed murderer and betrayer of the Thieves Guild. It is full of leveled draugr, and at least one undead boss.

The second zone contains a word wall for the Disarm dragon shout, making the related quest and its five prerequisite quests necessary to unlock all three words of Disarm.
 
Related Quests
 
 
 

Walkthrough
Exterior
During the related quest, there will be a tent, two bed rolls, and Karliah's dead horse to the south of the entrance to the ruin. Several random items can be found on the dead horse, including potions and poisons. Mercer Frey will be in front of the barrow entrance and will initiate conversation as you approach, confirming he was the one who killed Karliah's horse to prevent her escape. Only Mercer can unlock the door into the ruin, and followers are unable to enter. There are two barrels of ingredients and two food sacks to the left of the entrance, and blood splatters on the ground in front.

There is an alternative entrance to the northwest, but the way is blocked by an impassable gate until you've passed through the entire ruin from the main entrance.

Snow Veil Catacombs
The interior of the ruin is filled with traps set by Karliah for Mercer Frey, as well as the normal traps found in typical barrows, including bone chimes to wake the draugr she also left for you to deal with.

Upon entering, as with many other Nordic ruins, you'll be at the top of a set of narrow stairs. At the bottom of the stairs is a cluster of Nordic barnacles and an iron helmet on the ground. Continue through the first room and down another flight of stairs to a room containing two urns, two burial urns, a dead draugr, a pull chain, an apprentice-level trapped chest, and two ominous upright sarcophagi. Opening the chest without disarming the trap will trigger the sarcophagi to burst open and draugr to attack. There are two gates in the corners of the north wall operated by the chain on the south wall; however, the right-hand gate has a cave-in behind it and won't open. Behind the left-hand gate is an alcove with a random potion of healing, a random potion of stamina, and a small coin purse on a set of shelves. A doorway to the east descends to the next room.

This room contains several more sarcophagi, all of which are already open with draugr inside. One of these is leveled and only slumbering, but will only wake if you attack it. There are three more dead draugr lying on the ground, and a woodcutter's axe in front of a gate in the south wall. There is a chain to the right that opens it, but also triggers a spike wall to the right. To avoid the spikes, immediately jump back once you pull the chain.

Follow the passage as it takes a turn before reaching a typical catacomb area with upright alcoves and many burial urns; many of the alcoves contain slumbering leveled draugr. The second small section of the catacomb features an adept-locked iron door, beyond which is a small alcove containing a sideboard with a random potion of healing, a random potion of stamina, and two random potions of magicka on top, with an ancient Nord sword and an ancient Nord war axe on the shelf underneath. There are three bear traps on the ground in the next small section of the catacomb, and a draugr patrols the next corridor. A total of eight draugr are in this area, many leveled, with two tripwires that cause two nearby oil lanterns to fall to the ground and ignite an oil slick. A chest lies against the east wall by the oil slick among some rubble, and to the south is a lowered gate, with the chain that opens it to the left.

Beyond the gate are stairs leading down to a passage with two draugr on guard. A short passage is on the left, and an apprentice-locked door is ahead. There is a flute and three loose septims lying on the ground before the door. Behind the door is a small room containing three large urns, three burial urns on a stone table, an unlocked chest, and an empty set of shelves. There is also a barred opening acting as a window into a two-level room farther ahead, with several leveled draugr and skeevers wandering in and out of view. It is advisable to use ranged attacks from here to avoid a potentially difficult fight later. The passage on the left leads into a room with many bone chimes hanging from the ceiling; around the room are five upright sarcophagi, up to four of which contain slumbering leveled draugr. There is a sideboard to the southeast with the Sneak skill book Three Thieves and three random potions on top: one healing, one magicka, and one stamina. To the east is a closed gate, with a chain to the right to open it. 

thumb|right|The Model ShipThe passage behind the gate descends several flights of stairs and takes three turns before entering the room seen from the window. As you near the entrance, one of the sarcophagi in the room will burst open, and a magic-using draugr will emerge. There are stone stairs to the right and wooden stairs in front leading up to two balcony areas. Taking the wooden stairs leads up to a balcony with two sarcophagi; one is open and contains a dead draugr, while a set of shelves by the other holds nothing but clutter. Between the two sarcophagi is a passage patrolled by a leveled draugr. The passage eventually leads to a third balcony in the main room, with a trapped pedestal holding the Model Ship that can be sold to Delvin as part of The Litany of Larceny quest. The pedestal is surrounded by an oil slick, and has an oil lantern hanging above that is dropped when you remove the model. There is a potion of healing, a potion of magicka, a potion of stamina, an ancient Nord sword, an ancient Nord war axe, two ruined books, and two burial urns on sideboards around this balcony; these items may be blown about if the trap is triggered before you collect them. To avoid damage, leap off the balcony back to the bottom of the room as soon as you take the model. The stone stairs lead to another balcony, with two large urns flanking a passage heading south. This passage climbs and turns to the east, north, and east again. At the end it leads out onto a covered walkway that passes high over the main room below. By a pillar where the walkway turns is a salt pile on the ground by an animal skull. The walkway continues to an iron door, which opens into the second zone, Snow Veil Sanctum.

Snow Veil Sanctum
thumb|right|A barnacle cluster out of water...The Sanctum opens into more catacombs with the dead laid out in alcoves along the walls, some draugr only slumbering as before. Two draugr sleep on the left, and one sleeps opposite on the right. Sneak attacking any of these is likely to alert all three. There is a Nordic barnacle cluster on the ground just before the three sleeping draugr. Around the corner, stairs descend to an area with two chests opposite each other; one is unlocked, and the other is adept-locked, while each is behind a string of bone chimes. A total of five leveled draugr are in alcoves nearby; again, this can be a difficult fight for the unprepared. Once the draugr have all been dealt with, at the end of the room is another lowered gate, with the chain to open it on the left. Beyond the gate is a brightly lit area, with a pressure plate partially concealed beneath pottery that triggers a poison dart trap.

Around the corner, a narrow passage leads to another leveled draugr and stairs leading up. On the right at the bottom of the stairs is a burnt corpse, with a second burnt corpse at the top lying beside a dead draugr in the middle of the passage. Behind the dead draugr is a pair of open double doors, with a wide passage beyond. At the end is a pair of closed double iron doors. As you approach, Mercer will warn you to be ready, as the door is perfect for hiding an ambush. Opening the door causes two draugr (one of them a boss, which at higher levels may be a dragon priest) to awaken and burst from their sarcophagi on a raised area in front of you. There is also a sarcophagus at either end of the room to the east and west, with each containing a draugr that will burst forth and attack if you get too close or make too much noise. At the rear of the room behind the central raised section is the word wall, which teaches a word for the Disarm dragon shout. There are wooden stairs leading up to the raised section both in front and behind it, with a stone table to the left of the front stairs holding a copy of the Light Armor skill book Ice and Chitin. There is also an unlocked boss chest on the raised section. To the east is another lowered gate, with the chain to the right.

The passage beyond the gate leads around to a short passage with three bear traps on the ground and a puzzle door at the far end. Mercer will take over and start talking while opening it. This is the only puzzle door in the game without a corresponding dragon claw. Once the door is opened, a cutscene plays.

Should you return after the events of Speaking with Silence, you can traverse the ruin again. The final room is a series of terraces up to an upright sarcophagus, with a lowered gate behind it, and the chain to operate it to the right. Behind the gate is a short passage to an iron door leading outside via the alternative exit. The only thing in the final room after the quest will be a lootable skeleton on the floor. Outside, flanking the alternative exit are two barrels of ingredients and a food sack. This exit is located west of the main entrance, midway between the main entrance and Whistling Mine.

Notes
Even after finishing the quest, followers will not join you inside.
There is a stone platform west-northwest of the entrance to the Sanctum with an inaccessible grate-covered well in its center. Two ice wraiths will periodically spawn here, and can often be seen fighting with a frost troll that spawns nearby.
Setting off the oil lantern traps in the room with the Model Ship before picking it up can cause it to be blown off of its pedestal, making it potentially difficult to find again.
Select the Model Ship through the console by entering  , then type   to move it to the player.

Bugs