The Elder Scrolls IV: Knights of the Nine is an official expansion pack for the computer role-playing game The Elder Scrolls IV: Oblivion. Announced on October 17, 2006 for release on November 21, 2006, the expansion was developed, published, and released in North America by Bethesda Softworks; in Europe, the game was co-published with Ubisoft. The Windows version is available either as a downloadable plug-in from the company website or as part of the retail-released Oblivion Downloadable Content Collection CD—a release that also includes all previously released official downloadable content available for Oblivion. The Xbox 360 version is available via Xbox Live Marketplace, and the PlayStation 3 version of Oblivion includes Knights of the Nine in its packaged release.
Knights of the Nine centers on a faction of the same name, devoted to locating and preserving a set of "Crusaders' Relics". Once found, these relics must be used to defeat the sorcerer-king Umaril, who seeks revenge on the Nine Divines. Knights of the Nine was generally well-received in the gaming press. Although it made little change to the basic mechanics of Oblivion, it was judged by reviewers to be a brief but polished addition to the game's main plot.