Knights of the Nine is a compilation that includes all the other Oblivion downloadable content released to date: Horse Armor, The Orrery, Wizard's Tower, Vile Lair, Thieves Den, Mehrunes' Razor, and Spell Tomes. Knights of the Nine features an all-new faction and quests for noble characters and answers many of the questions surrounding the Ayleid ruins found throughout Oblivion. Players can join a new faction and found their own order of holy knights - leading them into battle against a sorcerer-king and his demonic minions while exploring massive dungeons and searching for legendary relics - the holy armor and weapons of the Divine Crusader.