The Elder Scrolls IV: Oblivion

Notes:

castle, Knights of the True Horn guard for castle, Secret treasure vault, Upgrade the furnishings, a vintner NPC, a combat trainer NPC and a taxidermist NPC and also an ancient Dwemer Forge). It is available for free until 22 October 2007 and not available in all regions, only: Australia, Canada, New Zealand, United Kingdom and United States.