User blog comment:Zippertrain85/Top 10: Least favorite NPCs./@comment-6336669-20130819074943/@comment-6336669-20130822003933

Mhmmm because the Loading screen saying otherwise is wrong, as well as the majority of the articles on this wiki regard the need for the WGC. If the Empire dies via the AD, Ulfric claims the throne, while the kingdom is in chaos over the impending attack by the AD, and with Imperial supporters still putting up a fight. The AD comes in, cleans out the trash. Skyrim is owned by Elves.

If you fight the Empire, Skyrim has no allies. Literally. Ulfric treats the Dark Elves like trash, the Bretons he slaughtered, the Redguards are barely keeping it together themselves, the Empire is, well, dead. And the rest are either owned by the AD, or will be too busy holding out against them.

Joining Ulfric has some concequences in the lore. Bet you the canon ending is to join the Empire. There's no way the next game will feature an in-tact Empire, Aldmeri Dominion, and independant Skyrim. Two must fall. One will stand.