I love the Shivering Isles in Oblivion
Oblivion's Shivering Isles offers escapism with its unique quirks.

The Shivering Isles, the second and final expansion for The Elder Scrolls IV: Oblivion, transports players to the surreal realm ruled by Sheogorath, the Daedric Prince of Madness. This plane of Oblivion is bifurcated into two distinct regions: Mania, characterized by vibrant, whimsical landscapes, and Dementia, marked by its dark, oppressive atmosphere. The expansion delves deep into themes of duality and insanity, offering a stark contrast to the more conventional fantasy setting of Cyrodiil.
The central narrative revolves around the impending Greymarch, a cataclysmic event where Sheogorath transforms back into his original form, Jyggalag, the Daedric Prince of Order, who then seeks to obliterate the Shivering Isles. Players are chosen as Sheogorath's champion to halt this cycle of destruction. The storyline is rich with intrigue, requiring players to navigate complex quests, make pivotal choices, and ultimately confront Jyggalag to break the cycle.
Beyond the main quest, the expansion is lauded for its imaginative side quests and eccentric characters. Notable examples include the town of Split, where each inhabitant has a murderous double, and the haunting ruins of Vitharn, where ghosts are trapped in an endless loop of their final battle. These narratives are infused with dark humor and absurdity, enhancing the game's unique charm.
The Shivering Isles also introduces a plethora of new content: over 30 hours of gameplay, unique creatures like Flesh Atronachs and Grummites, and a variety of new items, spells, and dungeons. The capital city, New Sheoth, embodies the realm's duality, with its districts of Bliss and Crucible reflecting the contrasting natures of Mania and Dementia. This expansion not only extends the game's world but also enriches its lore and gameplay mechanics.
Critically acclaimed, The Shivering Isles is often regarded as one of the best expansions in video game history. Its blend of imaginative storytelling, memorable characters, and innovative gameplay elements offers a refreshing departure from traditional fantasy tropes, solidifying its place as a standout addition to the Elder Scrolls series.
Sources: Wikipedia, PC Gamer, Wired