Rannveig's Fast (Location)

It is located in the Rannveig's Fast area of the southern mountains of Hjaalmarch. It can be reached by approaching the southern-face of the mountains located south of Morthal. Upon approach, one will spy crumbling stone ruins and stone steps leading up the mountain to the entrance of Rannveig's Fast and further upwards towards South Cold Rock Pass. It is north-east of Rorikstead.

Walkthrough
The first room is an opening with plant life covering the ground including two Mountain Flowers. The next room contains a Subjugated Ghost in front of a table with potions. The third room opens up onto an overlook with a Subjugated Ghost seen patrolling below near some thistle.

These ghosts will apologize saying it isn't what they want to do, seemingly cursed. At the back of this room is an empty chest but there is a trapdoor that will send you falling two levels into a cage. (Avoiding the trap will provide you one of the words for the shout Kyne's Peace which soothes wild beasts.) Sild the Warlock will soon identify himself as your captor and also the one holding the Rannveig's Fast Key.

There are several methods to escaping Slid's Cage which has an expert lock. The easiest way to get out of the cage is to look in Slid's assistant's satchel/knapsack on the floor right next to the cave; it should have one key in it. On surviving the fall Slid will begin to monologue and continue on to searching for the proper poison to test on you. During this time you can pick the expert lock, one of the dead bodies floating in the water contains 32 lockpicks so you'll have plenty of tries. Alternatively you can sneak and pickpocket the key off of Slid while he's still close enough to the cage or open the satchel close by which holds the key to the door. Your companion may also open the cage door for you allowing you to get out. There is plenty of loot to be had in Sild's dungeon once you leave the cage. Killing Sild will give you his key, Black Mage Robes, and an Elven Dagger. The key unlocks the expert chest which contains a randomized amount of gold and weapons. Sild's Journal describes his trap and his desire to experiment on his prisoners. Dead bodies can be found locked in cages with the key, confirming that these are the bodies of the summoned ghosts roaming the area. The room is filled with various potions and poisons, as well as an Alchemy Lab. If you wait around for a few minutes, another bandit will drop down the trap door and die instantly.

Leaving Sild's dungeon down the hall to the left will have you encounter a Subjugated Ghost with a passageway on the left leading to a door that must be raised by the nearby lever. One path leads to the original room with the trapdoor, the other leads upstairs where another lever may be found.

Taking the upper path first will allow you to circumvent Sild's trap by opening the gate to the lower levels, thus giving you the drop on him. The path takes you across a bridge over the trapdoor room with a Subjugated Ghost in the next room along with and apprentice locked chest containing gold but otherwise a dead-end.

Leaving Sild's dungeon down the hall to the right will have you encounter a Subjugated Ghost with a dead-end wooden door on the right and an expert locked iron door on the left (can be unlocked with Sild's key). Behind the iron door leads to the way out of the dungeon as well as a chest.

You will find the Stone of Barenziah on the table next to the Alchemy Lab.

Word Wall
Transliteration and translation of the Word Wall inscription in English:

HET NOK KOPRaaN DO HELA Here lies body of Hela

FahDON Wah Pah SIVaaS Friend to all beast

aaR DO KaaN aaL REK SiiV UNahSaaL Servant of Kyne

PRaaN KO FeyKRO DO HahNU Rest in forest of dream

Enemies

 * 5x Subjugated Ghost (3 more outside)
 * Sild the Warlock

Items of Interest

 * Dragon Word Kyne, Kyne's Peace
 * Sild's Journal
 * Unusual Gem - Stones of Barenziah

Notable Loot

 * Iron Dagger of Torpor (or Iron Dagger of Shocks)
 * Skill Book: Horror of Castle Xyr (Destruction Skill Book)
 * Unusual Gem (Stone of Barenziah)
 * Diamond (inside of a basket near a corpse)

Alchemy
An Alchemy Lab can be found in Sild's dungeon.
 * 2x Mountain Flower
 * 1x Thistle