This is Ard Skellig, the largest of the islands that make up the region of Skellige in the world of the Witcher. Notably, Skellige was based on many of the same Norse mythological/cultural aspects as Skyrim, though with a few things extra, case in point being the Viking funeral practice of laying a dead chief on his his longboat with his shield, sword, bow, quiver, and several other things, then pushing it into the ocean and setting it on fire. Sovengarde and the Skellige religious afterlife were both based on Valhalla as well, which is Viking heaven. I can only imagine their underworlds were both based on Viking hell, literally known as Hel.
