The Shivering Isles is a downloadable content expansion for the video game The Elder Scrolls IV: Oblivion. Released in 2007, it introduces players to a new realm, the Isles, which is divided into two distinct regions: Mania and Dementia. Each area reflects the contrasting aspects of madness, featuring unique landscapes, creatures, and quests. Players assume the role of the Hero of Cyrodiil as they explore the Isles and interact with its inhabitants, including the Daedric Prince Sheogorath. The expansion offers new gameplay mechanics, items, and a rich narrative that delves into themes of insanity and duality.