Elder Scrolls IV: Oblivion is a first-person perspective fantasy computer role-playing game set in a vast 3D world with an open-ended storyline that allows the player the freedom to pursue the main quest, side quests, or simply explore the world. The game is set in a different geographic location from the previous in the series (Elder Scrolls III: Morrowind) and in general the architecture and wildlife is more medieval and real-world. The fantasy game art is vastly improved, however, and at the time of its release wowed the world with its realism and attention to physics in its interactivity.
This Elder Scrolls IV: Oblivion fantasy art / game art page has images from a graphically modified game. For an overview of the major changes, click here.
A fallen King has been unchained from the darkness of Oblivion to seek vengeance upon the Gods who banished him. Only a champion pure of heart can vanquish the evil that has been released upon the land. You must heed the call, reclaim the lost relics of the Divine Crusader, and return the Nine to glory. New dungeons, characters, quests, and mysteries await.
Knights of the Nine is an official expansion to Oblivion that presents a quest of moderate length to retrieve holy relics and defeat an ancient evil. What distinguishes this add-on from the rest of Oblivion is the emphasis on non-combat oriented tests/stories during the relic-recovery stage. It also adds new creature models (Umaril and his Auroran minions) and a suite of arms and armor.
Installing this add-on into an Oblivion game also results in the Chapel of Dibella in Anvil being immediately descecrated by evil forces.
The Unofficial Elder Scrolls Pages has detailed information on the quests in Knights of the Nine.