Alright, so, I had a closer look at your writeup, and I have some more detailed notes for you. If anyone else wants to have a look, I've underlined general worldbuilding stuff that is Neat To Look At.

[hider]
Primarily, I feel like Thalzamaria as you're presenting it just a bit too formal and organized for the setting. Remember that the region suffered an almost complete societal collapse fifty-some years ago. Just as food for thought, the first Fallout game where civilization is just starting to get back on its feet is set eighty years after the Great War. Now, here's the thing. [u]Thule honestly did not suffer quite as harshly as Atlantis and Iiram (largely because the Lemurian Horde directed its forces mostly southward), but the nation did balkanize severely.[/u] Thalzamaria could essentially be a fragment of the original Kingdom of Thule that has more deeply entrenched itself in the Lemurian/Hyperborean-influenced culture of its region.

Basically what I could see happening is something like this: Thalzamaria was once a proud province of Thule near the northern border, but was basically reduced to semi-tribal city-state following the Years of Dusk. They had an intense rivalry with a neighboring Lemurian tribe, and eventually the Thalzamarian king decided to conquer and subsume their enemies (the sort of desperate barbarism implied in this act of depravity was something I liked in your writeup), and had Khalaevna. He abandons Khalaevna, she joins with a Hyperborean tribe, the rest is history.

She probably wouldn't even need to "assassinate" Carthain, just kill him and tell his clan that she's the boss now. I[u]magine Hyperboreans as being Norsemen as imagined by the rest of Europe: savage and murderous thieves and barbarians. In the Age of Dawn, they also suffer greatly from mutation and have a great number of warlocks and other dark mages among their ranks. Basically in short, the Hyperboreans aren't [url=http://vignette3.wikia.nocookie.net/elderscrolls/images/f/f4/Stormcloaks_Solitude.png/revision/latest?cb=20120513073552]these guys[/url], they're [url=https://1d4chan.org/images/7/78/Northlanders.jpg]these guys[/url].[/u]

Uhh, on to more nitpicky stuff.

Taynthrill seems kind of unnecessary. [u]Fantasy metals have been a thing in Borea for a long time, mostly as a product of alchemy, though each empire had their own sort of flavor to it. The distinct masters of alchemical metallurgy were the Atlanteans, who conquered Borea in ancient times with an army of golden Orichalcum-clad warriors. Thule's speciality is GUNPOWDER, and A LOT OF IT. Cannons, mortars, muskets and petards are what allowed Thule to break away from the Atlantean Empire and establish itself as an independent power.[/u] I'm sure you can work with this.

I don't mind the Trogoikos so much as long as they aren't sapient. [u]I'm taking a "humans+" approach to races in this setting; if they're sapient, they must be human, or some form of human derivative (e.g. vampires, mutants, etc).[/u] If you wanted to, you could call them a subspecies of feral cavemen that live holed up in their tunnels.
[/hider]