Castle Karstaag Ruins is a cave system on the north-western edge of Solstheim, added with the Dragonborn expansion. Once the seat of a legendary frost giant, it is now firmly in the hands of rieklings and their pet bristlebacks. People go there for two reasons: to fight one of the toughest summonable foes on the island, or to recover a missing smithing formula from a less fortunate visitor.
What you’ll find
- Plenty of rieklings throughout the caves, plus a bristleback pen near the top of the main chasm.
- The body of Esmond Tyne, lying on a small icy shelf to the left as you enter the main chasm.
- A riekling outpost at the top of the chasm: past the bristleback pen and across a bridge, two rieklings guard an unlocked boss chest. Behind it a skeleton rests beside a leveled shield and mace.
- Opposite the boss chest, at the same end of the bridge, a path up the rock face leads to a locked chest and a piece of leveled armor.
- An area above the waterfall in the main antechamber with a skeleton, some gold and a chest, if you can climb up there.
- The ruins connect to the deeper Castle Karstaag Caverns.
Quests
- Summoning Karstaag – call up the ghost of Karstaag and challenge him to a fight. Bring your best gear; he isn’t a pushover.
- Glover Mallory’s formula – the Raven Rock smith wants his Bonemold Formula back from Esmond Tyne’s body. Reading it lets you craft Improved Bonemold Armor at a forge.
Notable items
- Bonemold Formula on Esmond Tyne.
- Boss chest at the top of the chasm, plus a locked chest and leveled armor up the cliff path.
- Lots of riekling leftovers: Riekling Spears, boar meat and Dibella statues.
Tips
Grab the formula first – Esmond is right by the entrance, so you can finish that errand before the real fighting starts. Rieklings come in numbers, and bristlebacks hit harder than their size suggests, so a sweeping weapon or area spell pays off here. Collect the Riekling Spears as you go; someone at Thirsk Mead Hall may want fifty of them. If you explore the ledge above the waterfall, step carefully: the rocks there have collision problems and you can drop through the floor (the game usually puts you back inside the cave).
Nearby
Closest places on Solstheim covered on TamrielSaga: Castle Karstaag Caverns, Northshore Landing, Saering’s Watch, Stalhrim Source, White Ridge Barrow.
Map position and editor ID read from the Dragonborn game files; details checked against community wiki articles and summarised in our own words.
