You may all remember that the original version of this thread stated that this game takes place in 4E 471. This is no longer true; despite it not having a true bearing on the story, other than the relevance of the events of Skyrim, it should be known that this game will actually be taking place in 4E 279. This means that, yes, the Dragonborn is in fact more than a myth, the assassination of Titus Mede II is fresh Imperial history, and all other major events of Skyrim will hold some level of import in our story.
In my version of the Elder Scrolls timeline, the Civil War that wracked Skyrim following the ban of Talos by way of the White-Gold Concordat ended, officially, in a Stormcloak victory. Ulfric's rebellion pushed the Thalmor and Imperials back with the essential help of the Dragonborn, and set up a new, independent monarchy with Ulfric on its throne and Windhelm as its capital. His son, Galifried, took Ulfric's place following his death in 4E 243, and has ruled to the time of this game.
Due to the Stormcloak victory, Skyrim has grown in power in all aspects of the word; however, political tensions grow with Black Marsh and Morrowind due to the leftover Xenophobia from Ulfric's rule.
The Argonian homeland, inspired by the Stormcloak victory, also seceded from the Empire some time after the Civil War with little struggle from the weakened Empire. More mysterious and insulated than ever before, all that is known to outsiders is that the shadowy An-Xileel political faction has taken full control of Black Marsh's government.
The Empire is weak, having lost all but three provinces to independence (as with Black Marsh and Skyrim) or to the Aldmeri Dominion. The three that remain are High Rock, Hammerfell and, of course, Cyrodiil. The current Emperor is one young Lupus Mede I, grandson to Titus Mede II.
The Aldmeri Dominion has only grown in power, surpassing the Empire post-Great War. The White-Gold Concordat is still in effect publicly, but Altmer expansion has definitely left the current Emperor uneasy. Under the rule of the oligarchical Thalmor, the Aldmeri Dominion now consists of the Summerset Isles, Elsweyr and Valenwood, as before, but also has incorporated the dunmer province Morrowind.
For this game, know that the Dark Brotherhood, Morag Tong, and Shadowscales are all entirely active in this time of political unrest and open for players to participate in. Other factions, like the Thieves' Guild or Companions should simply be assumed to be active. There are, however, a handful of altered factions/homebrew factions that you should be aware of:
In my version of Elder Scrolls, the Vigilants have become a nation-spanning mercenary force that takes jobs in exterminating daedra, their followers, and other wicked perversions of nature such as werewolves and vampires. Though they are paid for their work, their surcharge is very minimal, as they live lives akin to those of traveling monks and merely offer their services for the purpose of serving their patron god, Stendarr. Though present in all provinces, Skryim and Cyrodiil seem to be their main nations of operation.
As a hard counter to the Vigilants, the Light of Namira is, as the name suggests, a widespread cult that worships the goddess of the grotesque. These cannibalistic cultists hold much influence politically in the Empire and Dominion, and are thought to worship other allied Daedra as well (such as Sanguine, Molag Bal, and Boethiah).
This is an entirely original group, very obviously based off of my homebrew Star Wars faction known as the Krayt's Jaw Cartel. Another obvious observation is that they are a pirate fleet, led by a proxy of my usernamesake character, the half-altmer Cerce. They are powerful and well-known, and take advantage of this politically charged continent by raiding trading operations between the Empire and Dominion. This faction is open for players, but not until later in the story can those characters begin being written.
Magic, in my opinion, is pretty open. Anything you can think of that's not overpowered, I imagine your character could do it with sufficient training. For instance, Skyrim shows us that Destruction magic exists in the three forms of Shock, Frost, and Flames. Well, who's to say you couldn't use Water magic? Or Earth Magic? Or summon familiars that are entirely unlike atronachs or spirit-wolves? In terms of magic, just do you, but of course list it all in your biographies.
This is somewhat unimportant, but I feel the need to mention it if it ever comes up. In my canon, the major questlines of Skyrim, with the exception of the main storyline, were not performed by the Dragonborn. The Listener of the Dark Brotherhood, the Harbinger of the Companions, the Nightingale of the Thieves Guild, and the Archmage of the College of Winterhold of 4E 201 were all different, entirely separate characters, and the Dragonborn performed the actions of the Dragonborn DLC and Dawnguard DLC on the side of the Dawnguard. This same sort of logic would apply to the Hero of Kvatch, as well as... all the other player-characters of the main series, but they're so unimportant to this story that I won't bother listing that.
Now for some notes so that you all have a suitable reference to have your minds wrap around when perceiving the setting around you. These are subject to change, pending suggestions by you guys that I am totally open to hear.
By "scope" I mean how big you and I are imagining the world. This is something I struggled with, as (as we all know) the games don't exactly lend us very realistic sizes of things. I mean, if we're honestly thinking about it critically, all the major cities presented to us in the third, fourth, and fifth games are about the size of a neighborhood relative to the player-character. Not to mention, the whole province of Skryim can travelled across in about twenty minutes and even less if you go straight from one corner to the other running.
Of course, this won't be the case in our game. For the sake of simplicity, let's use simple language and imagine that each major is the size of Skyrim itself as represented in the game, and everything else can be adjusted in our minds accordingly.
Honestly, you can imagine this world in whatever way you like, as I'm writing it in a heavily literary style, but I will personally be imagining it all matching the aesthetic of these retexture mods, since I do like to imagine it in a video game.