|The Elder Scrolls III: Morrowind
The Elder Scrolls III: Morrowind is an epic, open-ended single-player game where you create and play any kind of character you can imagine. Be the noble hero embarking on an epic quest, or an insidious thief rising to leadership of his guild. Be a malevolent sorcerer developing the ultimate spell of destruction, or a reverent healer searching for the cure to a plague. Your actions define your character, and your gameplay changes and evolves in response to your actions. Confront the assassins' guild, and they take out a contract on you. Impress them, and they try to recruit you instead. No two sagas are the same in the world of Morrowind.
Native alternative: OpenMW is a reimplementation of the Morrowind engine that runs natively on Windows, MacOSX, and Linux. It still requires the user to have a legal copy of the game assets, which can be installed in Wine and then used by OpenMW.