Arx Libertatis is a cross-platform, open source port of Arx Fatalis, a 2002 first-person role-playing game and dungeon crawler developed by Arkane Studios. Arx Fatalis (Latin for "fatal fortress") is set on a world whose sun has failed, forcing the above-ground creatures to take refuge in subterranean caverns. The action in Arx Fatalis takes place in one of these large caves, where inhabitants from all races such as Trolls, Goblins, Dwarves, Humans, etc. have made their homes on various levels of the cave. The player awakens inside a prison cell and, after making his escape, eventually discovers his mission is to subvert and imprison the God of Destruction, Akbaa, who is trying to manifest itself in Arx.
WWW: https://github.com/arx/ArxLibertatis