The short version:
If TES VI really is Hammerfell, several books have already done the setup work. No need to invent a new history when the gaps are already marked.
I went back through the Pocket Guide to the Empire (3rd Edition) and the Redguard-specific texts on UESP this week. The material is thin in places but consistent where it matters.
Yokuda's fall and the Ra Gada arrival
The sinking is dated to roughly 1E 792 in most accounts. The Exodus and the oral histories referenced in Redguard place the event after a series of internal wars on the lost continent. The survivors who reached Hammerfell called themselves the Ra Gada, and the existing populations they displaced or absorbed left their own traces in later Redguard law and naming customs.
The timeline sits between the Alessian Order's rise in Cyrodiil and the early Second Empire. That overlap is rarely used in fan discussion but gives a ready-made point of contact with the west.
The Ansei and the Shehai
Sword-singing is the part most people remember from the game Redguard, yet the details stay thin outside that title. Words of the Masters and scattered lines in the Pocket Guide are the main written sources. The ability is treated as both martial technique and cultural inheritance, lost or diminished by the time of the game's events in 2E 864. Any story set later would need to decide whether the art stayed buried or re-emerged.
The Forebears versus Crowns split
This division appears in almost every Redguard text after the Ra Gada landing. The Crowns kept closer to Yokudan tradition and settled inland; the Forebears adopted more of the coastal and trade practices. The conflict flares again during the Tiber Wars and is still referenced in Skyrim-era books such as The Great War. It is the clearest ongoing political fault line the lore provides.
The Alik'r desert itself is treated as both homeland and barrier. The Alik'r book in Skyrim gives a short but pointed description of the nomadic warrior societies that still operate there. That text is short enough that most players skip it, yet it lines up with the older Redguard sources on how the desert shapes identity.
If Bethesda uses Hammerfell, these pieces are already on the table. The question is which ones they treat as fixed and which ones they leave open for the player to shift.
So which of these threads, the Ansei decline or the Crown-Forebear split, feels more likely to drive a main quest? And do you read the silence around post-2E 864 Redguard events as deliberate setup or just an area that never got expanded?