The Soul Cairn is a plane of Oblivion haunted by lost souls, added by the Dawnguard add-on.
You will visit the Soul Cairn during the course of the add-on's main questline, either as a Vampire Lord or as a member of the Dawnguard. The Soul Cairn is primarily inhabited by Souls, wandering non-hostile spirits that were sent here because they were soul trapped before being killed. If you talk to these spirits they will usually comment on how lost or confused they are, or how desolate or horrible the Soul Cairn is.
Soul Husks are the only thing that grows in the Soul Cairn, and can be used to counter the health-consuming effects of the giant floating gems that may be found at the top of the various structures found throughout the Soul Cairn. Soul Husks can also be traded with the spectral merchant Morven Stroud for various items. Soul fissures are another common feature of the Soul Cairn; they are gaps in the ground with air rising visibly out of them, which causes them to emit a hissing noise. If you activate a soul fissure it will fill the largest soul gem in your inventory.
While traveling here you will be randomly attacked by Mistmen, Bonemen, and Wrathmen. There are also a few unique creatures to be found here, namely, Durnehviir, the three Keepers, and the Reaper.
There are various structures scattered throughout the Soul Cairn. Most of these ruined buildings contain a chest with random loot, typically guarded by the various hostile creatures found in the Soul Cairn. Sometimes, these structures may have gates barring your way, and near these you will see stones with glowing bluish-green balls inside them. Using a ranged attack on these orbs will lower the gates and allow you passage. You may also find well-like structures dotting the landscape. Most of them emit a purplish-white glow that comes out of the top, similar to the focus points in and around the College of Winterhold; jumping into these causes your health to regenerate. Also, there are smaller wells that do not glow; jumping into these will teleport you to a nearby, previously inaccessible location. Yet another possible find in these structures is a lightning rod, which is activated by placing a grand or greater soul gem into it, which will cause lightning to strike it and turn it into a black soul gem. Be aware that using the lightning rods will summon several hostile creatures. Interestingly, if you look straight up at the sky you will see a giant black hole in the center, much like Sovngarde.
For more information on the Soul Cairn, see the lore article.
 Related Quests
- The Soul Cairn may be re-entered at any time. However, if you enter as a vampire, and then are subsequently cured of vampirism, you'll need to become a vampire again in order to re-enter.
- As the Soul Cairn is technically outside, it is possible to use the Storm Call shout to summon a storm. The area becomes cloudy and almost appears as if it's part of Tamriel.
- Soul Cairn is roughly shaped like an upside down (larger part up) figure 8 when viewed from the entrance stairs. It is oriented southwest at these stairs to northeast at the Boneyard entrance. There are two massive walls. One divides the figure 8 with about 1/3 on the entrance stairs side with one gap roughly in the center. The second wall separates Soul Cairn proper from the Boneyard. Both walls run roughly northwest to southeast. The Boneyard doorway is very close to the northeast corner where the wall and the hazy blue barrier meet.
- If you turn back into a vampire in the room containing the entrance to the Soul Cairn, you'll need to exit and re-enter the room before you'll be able to re-enter the Soul Cairn.
- It's possible for the "soul drain" visual effect to stick to your character, even when not in range of one of the giant floating soul gems. The health drain effect does not follow, but it can become visually obstructive. This is easily remedied by walking within range of one of the soul draining gems without using the effects of a soul husk, and then stepping away.
- The Conjure Mistman spell tome may be stuck at the bottom of the podium with only one corner visible and not able to be grabbed.
- A workaround is to press ~ to bring up the console and enter
tcl to enable noclipping and go underneath the pedestal to get it. Go back aboveground and enter
tcl to disable noclipping again.
- You can also shoot an arrow at it to knock the book down, then go and grab it.
- It is possible to get beyond the blue barrier surrounding Soul Cairn. In the first half of the world, access an enclosed area (where page 3 can be found) through a building located to the left of the passage to the other half. There is an invisible gap between the wall to the left and the barrier.