A perpetual objective for players is to improve their character's skills, which are numerical representations of certain abilities. The game continues the open-world tradition of its predecessors by allowing the player to travel anywhere in the game world at any time and to ignore or postpone the main storyline indefinitely. Taking place within the fictional province of Cyrodiil, Oblivion 's main story revolves around the player character's efforts to thwart a fanatical cult known as the Mythic Dawn that plans to open portal gates to a demonic realm known as Oblivion. It is the fourth installment in the Elder Scrolls action fantasy series, following 2002's The Elder Scrolls III: Morrowind, and was released for Microsoft Windows and Xbox 360 in March 2006, and on PlayStation 3 in March 2007, with a mobile version of the game released on May 2, 2006. The Elder Scrolls IV: Oblivion is a 2006 open-world action role-playing video game developed by Bethesda Game Studios and published by Bethesda Softworks and the Take-Two Interactive division 2K Games.