Manjuice Nutella
Arcane
No, they were not. The Argonians advanced until Almalexia, the Telvanni territory outside Vanderfeel was left intact.Telvanni or bust. Where are the Mage Lords?
Dead. Killed off by Argonians.
As a matter of fact the Telvanni must be the most powerful faction on Morrowind, the rest was either conquered by the Hist or swallowed by a sea of ash.
Here, witness my detailed representation of 4E Morrowind:The Telvanni Isles are the most northeastern isles of Tamriel, located in the Province of Morrowind, in the Padomaic Ocean. As the name suggests, they are controlled by House Telvanni. The twisted fungi and vegetation influence the way the Telvanni construct their towers.
The main settlement and harbor is Port Telvannis
I was drunk when I wrote this, and I'm not an expert on TES lore, but that's more or less the impression I got.
The Argonians invaded Morrowind after the Red Year etc. mainly focused on the revenge on Telvanni. It's likely they weren't hostile towards the Hlaalu, and knowing Helseth, it's possible that he may have schemed against the Telvanni, if he was alive. Then there's Brand-Shei, who was born to the Dunmer of highest tier in Telvanni structure/social ladder, the main target of Argonians, and apparently the succeeded, Brand-shei being the "last living heir" and all - they were fixated on killing the worst baddest guys, like Therana, then going back to the Black Marsh.
We have little idea who died and who didn't, it isn't very clear what happened lately, and I doubt new Beth writing stuff gives a fuck. Logic dictates that the northernmost part of Telvanni territory would be mostly where it's at, and from where it could've spread to Solstheim, as shown in Dragonborn trailer, but ultimately it's all a subject to Bethesda's whims and retcons. It's easy to imagine Divaith Fyr being obliterated in wrath of Bethtards bent on blowing up Morrowind for the lulz.