Ok, to introduce this, I'm making a Morrowind mod which aims to recreate Stros M'Kai. This being a Morrowind mod, it will take place during Morrowind's timeline, 3E 327.

The last known significant events before this time took place during Redguard's time period, 2E 864, N'Gasta was defeated, the Dragon was slain, the Empire was overthrown, and The Treaty of Stros M'Kai was signed. Of course, more local specific events occurred in this timeframe as well, the Yokudan Camp on Northern Stros M'Kai was destroyed, leaving all but one survivor, the only known Dwemer Airship was destroyed during the second Rebellion, and the Goblin King in the caverns below the island was killed, not to mention many of the puzzles the Dwemer left behind in their ruins were solved by Cyrus, and their great Centurion was destroyed.

Now, 459 years lie between Redguard and Morrowind's settings. As the Dragonborn DLC has shown, a lot can happen in even a couple hundred years. So what happened during the time between the two games on Stros M'Kai? Of course, all we can really do is speculate, as there seems to be quite a lack of lore telling of what happened on the island in this time, but we can use our knowledge of the events of Redguard to guess.

For my mod, I've speculated a number of things.

• The Imperials have been driven off, a lot could have happened as a result of this:
  
  • The Dwemer ruins on the island would no longer be excavated by Richton and his troops, leaving them open to whoever, I speculate that at the Mages Guild on the Island's request, they are permitted to explore and excavate the ruins.
    
  • The Old Quarter could have been rebuilt, as a symbol of Redguard victory. I also imagine to lift the spirits of residents, a statue of Cyrus defeating Nafaalilargus would have been built, since it was the same Dragon that originally destroyed the Old Quarter.
    
  • Iszara took the throne of Stros M'Kai, and the Restless League no longer would have needed to hide out in their cove, leaving it's fate unknown.
• The Imperial settlers would still need a place to go, so I speculate they would have rebuilt the town of Saintsport, on the Southern portion of the Island, I also speculate a smaller settlement would have been made on the northern tip of the Isle of N'Gasta, which was freed of undead after Cyrus killed N'Gasta the Sload Necromancer.
  
• The Yokudan camp would no longer exist, instead, the only thing that would remain would be the ruins of a settlement where the camp used to be.
  
• Not being maintained by N'Gasta, the Necromancer's tower would have fallen into decay.
  
• Since the Mages Guild would be studying the Dwemer Constructs on the Island, I speculate they would have set up a small camp outside the Orrery to guard it from those seeking to steal the artifacts found inside, or generally profit at it's expense. They would of course also be maintaining it and studying it themselves.
  
• Additionally, since the Dwemer ruins on the Island were still filled with dangerous constructs, not to mention potentially harmful decay, they would only be studying the first levels, leaving the player to explore and discover it's secrets themself.

Now in addition to the discussion of my speculations, and the making of further speculations, I have a few questions.

Though as far as I know there isn't any official name for the Dwemer Ruins on Stros M'Kai, seeing as how the Rourken Clan found Volendrung on Stros M'Kai, built their capital there, and named the land Volenfell, would it be appropriate to name the ruins there that? I think giving the ruins their own name rather than just naming them "Stros M'Kai Dwemer Ruins" or something similar would give the mod much more depth and make it a lot more interesting.

What are the origins of the ruins on the Isle of N'Gasta? UESP says that the island was likely used as a graveyard for criminals, which is what would have made the island a perfect place for a necromancer like N'Gasta to set up their base of operations. However, the Necromancer's Tower, and the ruins surrounding it didn't look to be of the same origin of the Cemetery on the Northern half. Did N'Gasta build the tower? This seems unlikely, as the Sload aren't really known for building things, other than their Coral kingdom of Thras, but it being a Necromancer's tower, I'm lead to believe that N'Gasta built the tower. Then that leaves the ruins, they are particularly grim in design, with skulls carved into the walls, and other deathly designs. While they do seem fit for a cemetery of criminals, shunning the departed like that, they seem to mark the end of the cemetery itself, as south of the northernmost ruin, there aren't really any tombstones, at least as far as I can remember.

What happened to the town of Saintsport? I couldn't find any back story on why it was destroyed, and I don't seem to remember there being an explanation in Redguard. Was it ever explained? The architecture seemed Imperial in design, it doesn't make sense to me they'd let their own settlement be destroyed like that, so what happened?

If N'Gasta were to have been trapped in his own Soul Snare, would it be possible for him to bring himself back to the mortal plane somehow? I have an idea for a quest that revolves around this theory, so I'd be interested in knowing if it could happen.