Arx Fatalis is a video game developed by Arkane Studios. The game is set in a bleak fantasy world where the sun has gone dim, and nations have to tunnel below the ground to stay warm. The player avatar is a man who awakes without a memory in a goblin prison, and has to travel the subterranian world to discover himself.

Throughout the world, in any population center, the player can find Sisters of Edernium. These serpentine women are a complete mystery to everyone; no one knows who they are or where they come from. They are the only source of magic in the world, however, and they offer their services to anyone, so no one minds their presence.