Castle Karstaag Caverns

The Castle Karstaag Caverns consist of a small, multilevel cave in . They are located in the northwestern section of the island of Solstheim, east of Northshore Landing and west southwest of Glacial Cave.
==Sublocations==
===Castle Karstaag Courtyard===
This is reached at the end of the caverns. There is an exit here to Solstheim, as well as Karstaag's throne. It is also known as the Castle Karstaag Ruins.
==Walkthrough==
At first, this is the only way to enter the Castle Karstaag Ruins, since the door to the Ruins are locked beforehand and the Dragonborn only is able to acquire a key to the door after defeating and looting a Bristleback inside.
The cave starts heading west next to a stream, then turns left (south) where it opens to a large body of water filled with ice that must be swum across. Against the left (south) wall is a small ice shelf with the corpse of Esmond Tyne. It has some random loot, as well as the Bonemold Formula, which can be returned to Glover Mallory to complete the miscellaneous quest "Paid in Full." There are several rieklings in the area shooting their spears from above. On the right side is a large ice shelf that can be climbed onto. At the southern end of the room, in front of a waterfall, is a bridge. Across the bridge to the left (south) is a riekling camp containing a knapsack with leveled loot, plus a riekling hut. Under the water beneath the waterfall is a locked chest.
Back across the bridge, another cave leads west, where more rieklings are found. The cave narrows, then turns right (north). It opens to a small room with several more rieklings around a campfire and a raised, fenced area that cannot be reached yet. Turning left (west), another cave leads to an ice-covered door.
Beyond the door, the cave drops down to where the floor is covered with water. then turns north. There is an novice-locked ice-covered door along the right (east) wall with minor loot behind it. The cave then comes to a T intersection. To the left (west) are two doors - a novice-locked door to the right (north) with nothing behind it but a soul gem, and an apprentice-locked door to the left with nothing behind it but a riekling corpse.
Back at the T intersection, to the right (east), a short path leads to a door. Behind the door, the cave leads up out of the water, then turns right to the raised platform seen earlier. On the left (east) end of this platform, a short passage leads back to a riekling camp that overlooks the first large room in the cavern, with a bridge that spans this level. Before crossing the bridge, a very narrow ledge against the right wall leads to a few soul gems and a riekling hut with random loot.
Across the bridge to the east is another riekling camp with several more rieklings. Beyond that, a cave leads up to another large room with boxes to the right that have an apothecary's satchel lying on top. To the left (north) is a ramp down to the ground floor of the room, where three bristlebacks and a riekling are found next to another waterfall. In a crevice to the southwest is a novice-locked chest with a Dibella statue.
Back up at the entrance to the room, the path continues south, turns right (west), and leads to a door that opens onto an even higher overlook of the first large room in the cavern. Another small riekling camp here has two rieklings protecting it. A bridge leads west across this highest level of the room. At the other end of the bridge, another bridge to the left (southwest) leads to another camp with more rieklings, another riekling hut, and a chest next to the water containing leveled loot.
A path leads west, then turns right (north) and leads to the Castle Karstaag Courtyard (which is synonymous with Castle Karstaag Ruins).
===Castle Karstaag Ruins===
Upon arriving here, there is at least one mounted riekling, as well as several others who are not. The mounted riekling has the Castle Karstaag Key on its corpse. In addition, there is Karstaag's throne, which can be activated if Karstaag's skull is in inventory (obtained from Glacial Cave). See the Karstaag article for details. A master-locked door to Solstheim can be opened with the key.
==Quests==
===Paid in Full===
Glover Mallory's formula for creating bonemold armor was taken by Esmond Tyne, and he wants it back.
==Notable items==
*Bonemold Formula – found a few feet into the cave on Esmond Tyne's corpse.
==Trivia==
*Just before the exit to Castle Kaarstaag Courtyard, there are two hidden chests. Once across the last bridge, turn right and climb the ice until a ledge is reached, where the first chest and a set of random armor will be found.
**From here, go back a few steps and locate some stones embedded into an icy rock pillar, in order to climb a little higher. Then, follow the path that goes all the way around the pillar and faces the waterfall, and use Whirlwind Sprint to fly across the room and land on the waterfall ledge (in front of the second icy rock pillar). The second chest and a skeleton hanging over the edge of a waterfall can be found here, with a second skeleton at the bottom of the waterfall next to a mace and shield.
==Appearances== 
*  as Castle Karstaag
*
es:Cavernas del castillo Karstaag
ru:Пещеры замка Карстаг