Things from Skyrim that will be fact/canon in TES VI

[AeraDunmerMoon]

Despite the Civil War having 2 endings, there is something consistant in both: Elisef the Fair lives no matter what side wins (Only Tullius/Ulfric die). I assume the endings for each of the guild questlines happen no matter what, if only under different names (as it was in Oblivion, where the Listener didn't have to be the Champion lore-wise). DLC is generally considered lore (So Miraak kicks it).
As for choice-related things....I wonder if there will be another dragon break for things like which side of the civil war had more influence ( or if Elisef's survival makes it moot), how strong the Dawnguard become with/without Dragonborn support, or if the forsworn get their leader out of Markarth.

[MidbossVyers]

Sheogorath's dialogue in Skyrim implies that the person who Sheogorath used to be experienced the events of the Thieves Guild, the Dark Brotherhood, and Martin's sacrifice. If the Dragonborn joins the Volkihar, the Dawnguard are wiped out afterwards.

[AeraDunmerMoon]

Well, but which one will be lore? Or will there be some kind of break to make both possible lore-wise? Or will they be super vague about it?

[legoless]

I hope the dragons stick around for TES VI. They're such an interesting fantasy element that feels sorely absent in ESO.

The assassination of Emperor Titus Mede II is almost certainly gong to be canon, because that's a pretty significant event just to leave out.

That he died will be canon. That he was assassinated, maybe. That he was necessarily assassinated in the way we see in the game, no, because that would contradict player choice. No one will ever get "their way".

Not so - just look at Umbra. The player had the choice to save Clavicus Vile, but that player choice was discarded to fit the greater narrative. The Dark Brotherhood is too much of a fan favourite for the writers to cripple themselves by trying to cater to a throw-away "kill everythin" quest.

[Dark Spark]

No matter the fate of the Dark Brotherhood in Skyrim, time enough will pass to see Nelkir as the latest Listener of the Black Hand. He has a knack for hearing whispers from the epitome of murderers.