Prerequisites: Completion of the quest "Dawnguard"
Quest Giver: Isran
Region: Fort Dawnguard, Dimhollow Crypt
Reward: No specific reward, extensive items to be found as loot

Summary: You must fight your way through Dimhollow Crypt to reach the central chamber of Dimhollow Cavern. There, a puzzle must be solved and an ancient secret uncovered, which the vampires were tracking down.

Quest Description

Find out what the vampires are seeking
This quest begins while still inside Fort Dawnguard, and you can take the opportunity to question Vigilant Tolan about the Hall of the Vigilant, the Vigilants of Stendarr, and Dimhollow Crypt. He suspects that the vampires were after the knowledge and journals of Brother Adalvald, who was obsessed with vampire artifacts and burial sites. He then says goodbye and heads out to Dimhollow Crypt ahead of you, where he intends to support the player.

The entrance to the crypt is a cleft in the rock along the mountainous path leading from the Hall of the Vigilant to the Shrine of Mehrunes Dagon. Upon entering, you can hear two vampires talking about the foolishness of a Vigilant who came here alone despite the lesson taught at their hall. The foreboding is confirmed after defeating the 2 vampires - Vigilant Tolan fell after defeating 2 vampires and a death hound. In this first cavern room, you can recognize the ruins of an old Norse structure, which turns out to be a buried burial site.

The iron gate is opened...

...with a pull chain inside the fort-like structure opposite.

Through the iron gate, you reach a second cavern room containing Norse coffins as well as mounded graves. At least one vampire patrols here, and skeletons crawl out of the ground. The iron gate at the end leads to a third room with Norse coffins and an Arcane Enchanter. There are no enemies here, only dead Draugr. Via a flight of stairs, you reach a fourth, catacomb-like room where a vampire and a death hound are fighting against Draugr. To progress, you must turn against the victors. If you wish, you can also inspect the small rooms behind the 3 iron gates. After the catacombs, you reach a fifth cavern room with 2 waterfalls, a vampire fledgling, and skeletons crawling out of their dirt graves.

The sixth area is a labyrinthine catacomb room. Before entering, you only see dead spiders lying around. Detect Life will also lull you into a false sense of security, but you will still be attacked upon entering. The appearing vampires arrive accompanied by death hounds and additionally reanimate the spiders - you will suddenly have a lot to do in the narrow corridors. Depending on the selected difficulty level, this is a relatively difficult spot to pass. Once you have eliminated these enemies, you can rummage through several burial urns and chests before approaching a final iron gate. Behind it, a vampire master is fighting against a Giant Frostbite Spider. It is advantageous to hurry and help the spider first. If the vampire wins, he heals himself briefly and reanimates the spider. The two gargoyles to the left and right of the door do not fit the previous ancient Norse architecture and suggest different builders in the next area.

Through the door, you enter Dimhollow Cavern, a gigantic underground cavern, and witness the interrogation and execution of Brother Adalvald by two vampires. One of them - Lokil - was apparently tasked by a man named Harkon to investigate Dimhollow Crypt. The vampires forced Adalvald to lead them here and reveal his knowledge.

Excerpt from Adalvald's Notes on Dimhollow Crypt, Vol. 3

In the center of this vast cavern lies a stone island in an underground lake. Upon the island stands a complex ceremonial structure. It is surrounded by stone pillars connected to one another by arches.

The distinct architectural differences immediately catch my eye here as well: The stonework does not originate from the ancient Norse. Here too, there are additional gargoyle statues, just like the ones I first saw in the forward passages.

These statues do not exist anywhere else in Skyrim on any other Draugr burial ground. They are found exclusively in Dimhollow Crypt.

I am now certain that the large construct in this main chamber was erected long after the crypt... and by a different hand. It must have been the same builders who also placed the gargoyles in the crypt. Perhaps to deter the curious?

Once the vampires and their thrall have been defeated, you can take a closer look at the construct in the center of the cavern. Arranged around a central pedestal are 5 extinguished braziers. On the pedestal is a mysterious button, which you logically press. After a painful moment, swirling magical flames appear all around.

Solution to the Puzzle

The 5 braziers can be pushed. When all 5 are in their correct positions, the puzzle is solved. The order in which they are moved does not matter. However, there is a visual aid - the purple line of flame. Where it ends, the next brazier must be pushed. Initially, the first brazier must be pushed to the edge of the circle. Once it stands in the correct position, its contents ignite. In this image, the last brazier (left) only needs to be pushed inward, and the puzzle is solved.
Once all braziers have been moved to the correct position, they all slide outward on their own.

After this short preparation, the floor lowers slightly and reveals a stone monolith in the center. When activated, it opens and a mysterious woman falls out.

Speak to the mysterious woman
At first, she is somewhat dazed and asks who sent you. It does not matter what you answer, as the questions you can ask her are more important - for example, why she was locked away here. She admits to being a vampire, but is still a bit suspicious and promises to tell the whole story if you help her reach her family's estate on an island west of Solitude. This completes this quest, and the next one immediately starts, during which the conversation continues.

Known Bugs

• The Dragon Shouts "Marked for Death" and "Drain Vitality" somehow conflict with each other if Dawnguard is installed and a word of "Marked for Death" is learned. There is no fix for this. It is strongly advised to learn all three words of "Marked for Death" (Link) before exploring Dimhollow Crypt; otherwise, it might become impossible to learn any new Dragon Shouts.

Tips & Notes

• Before starting the quest, Dimhollow Crypt can be entered, but you will only find wolves. You cannot progress very far as there is no way to open the iron gate.
• In the second cavern room of Dimhollow Crypt, a chest is hidden on the upper right behind the first Norse coffin.
• When fighting vampires, keep in mind that they reanimate defeated enemies. Just like with conjurers, do not get distracted by this and focus on defeating the main targets first.
• The three rooms adjacent to the catacomb room are barred from the inside. One way to retrieve the partially valuable burial gifts is to use Telekinesis (or place a follower into command mode to drag the items closer to the bars).
• Skeletons are usually weak enemies. However, depending on the player's level, significantly stronger versions may appear. They can usually be recognized by the ancient armor pieces they wear.
• The skeletons here rise from the ground upon approach. It is impossible to see how many there are and exactly where they will emerge. The "Aura Whisper" shout is helpful to be prepared. However, Dimhollow Crypt is one of the few areas in the entire game where enemies are generated only upon immediate approach - such as in the sixth cavern room. Neither Detect Life nor even "Aura Whisper" will help there; you will be caught by surprise regardless. In the case of gargoyles, you are never safe from an unpredictable "reanimation".
• After entering Dimhollow Cavern, there is a chest located to the right of the stairs.