Why I love The Shivering Isles in Oblivion

There are lots of things to dislike about Oblivion. The yam-faced NPCs. The boring main questline. The speechcraft minigame. The levelling system that punishes you for not grinding secondary skills. While the last is inescapable without mods, the others stop being issues—or at least recede way into the background—when you go to The Shivering Isles.

There's a portal in Niben Bay that lets you escape the trad fantasy land of Cyrodiil. Bypass the guard telling you that only crazy people enter (and they come out even crazier), and on the far side you'll find a humble waiting room with a ticking metronome and a flat-voiced man waiting at a table. Does his collar make his bald head look like it's emerging from a flower? Yes, but everything else about him and this room is profoundly ordinary. Then you sit down, and in the tones of an officious immigration officer he tells you you're about to enter a land that's holy to Sheogorath, the Prince of Madness. 

Then the walls dissolve into light and butterflies, which swarm past to reveal a landscape of giant mushrooms under clouds like dancing fireflies. 

The Shivering Isles is split in two. Mania is a bright wonderland full of iridescent bug monsters whose blood will get you high. Dementia is a faded swamp full of glum people who would probably be better off drinking medicinal bug-juice. Prince Sheogorath is just as bipolar as his realm, his goofy ramblings usually ending with a grim threat. It's not a land to be taken seriously.

Which helps a lot. It's difficult to make a character in Oblivion who doesn't look like they've just been dug out of the ground, and Bethesda ran with that in creating the gurning stretch-faced goobers of The Shivering Isles. Their twisted smiles and wide-eyed leers take the cheek sliders to sinister extremes.

Sheogorath is rare in having two sides to his personality. Almost every other NPC is so focused on a single trait that to call them two-dimensional would be an insult to paper. Jayred Ice-Veins won't shut up about bones. Duchess Syl is paranoid about assassins and spies. Amiable Fanriene is afraid of walls falling on him while he sleeps. 

They're all extreme stereotypes with absurd vocal tics, and Bethesda's in-house voice actors clearly have a great time with them. A cast who struggled to portray the ordinary folk of Oblivion turn out to be better-suited to the cartoon exaggeration of The Shivering Isles, where everyone talks like the "Where is My Fish?" scene from Monty Python's Meaning of Life.

Which is why it's difficult to be upset by the portrayal of mental illness. There's a blacksmith who self-harms, which you can tell because her name is Cutter and every line of dialogue she has references cutting. Drug addicts and suicide risks are presented with as much sensitivity as the guy who is obsessed with one fork in particular. They're as subtle as Muppets and as difficult to take seriously. You may as well ding Miss Piggy for being an insensitive portrayal of narcissism.

Sidequests are the best thing about Oblivion, and The Shivering Isles is all sidequest. In the ruins of Vitharn you find ghosts fighting an endless siege, repeating the battle that led to their deaths. Work your way inside the fortress and you'll meet spirits who explain how their failures led to Vitharn's fall and damn them to this repetition. To free them, you have to break the cycle. Find arrows for the archer on the wall, find a power source for the wizard, find the doll the warrior is convinced he's married to—even here the characters are ridiculous—and eventually they'll change their fate and earn their freedom.

That's hidden in a corner of Dementia you probably find just by exploring, which is an act The Shivering Isles richly rewards. Work your way onto the roofs of Crucible, the Dementia half of the city of New Sheoth, and you'll find stashes of trinkets hidden away as well as a fight club who meet at night to bash hell out of each other. You may also stumble across Split, a town where everyone has a double—a wizard did it, they explain—and each wants you to murder the other. 

If you missed the bizarro fantasy of Morrowind, it and its giant mushrooms have been hiding in this corner of Oblivion the entire time.