Ostromarka – yet more D&D

I started thinking of yet another D&D setting – this one is for my horror ideas, nominally.

The idea was for Ostromarka to be the most distant, easterly outpost of the kingdom of Theudengard. Everything to the east, beyond Ostromark, is a blighted wasteland filled with demons and marauding orcs and probably a good few demons and hungry ghosts.

I was trying to picture it as a kind of late medieval, northeastern European, Slavic kind of vibe, where the winters are horribly cold and the summers are filled with dust storms and warm rains.

The area is under the rule of various Grafen (counts), all with different connections to the throne in the Capital (held by the Fürst). The area is held in name by a Landgraf, though political intrigues can be brought one when different Pfalzgrafen, with a more direct line of succession to the throne, arrive and make trouble. If the threat from the Wastes ever got too dire, the Landgraf might be booted out and replaced by a Markgraf (a more military commander).
Of course, why would the Landgraf ever let on to the Capital that there were such problems? Ad if he did, who among the lower ranking Ritter and Edler could he trust not to usurp him?

Ostromarka has a long history, longer than Theudengard, so the local Grafen are of course nominally at odds with the Fürsten, and therefore open to influences that might make them more powerful.
Ostromarka has been the eastern reaches of civilization since the fall of the Satrapies to their east hundreds of years previously. Succumbing to temptation by demons or the whims of their dark gods (or perhaps they were one and the same), the land itself became blighted, a burned out, baked, inhospitable terrain barely capable of supporting life. Its people also became twisted, allied with various different broods of demons and imps, and now the wastes are peopled with Orcs and Goblins and Gnolls, that continuously raid the lands near Ostromarka.
Tieflings and their demonic masters also roam the wastes, though they raid Theudengard in much more subtle and insidious manners.

Speaking of gods and monsters, the gods of Theudengard are many, though officially only one is worshipped.
The various cults of the Faith are fractured along lines of the identity and importance of the Prophet – whether he was a servant of a god, a god himself, a part of a god, and so on. One group believes he may have been a false Prophet, sent from a usurper to the true God.
Some escapees of the Satrapies passed their religion on to their descendants. The Faith believes them demon-worshippers, but most of these exiles believe their gods were usurped or their worshippers tricked in some way. They tend to worship in secret, mostly to avoid persecution.
The most secretive hide their worship from all but their most trusted fellows, for they worship ancient gods called the Elders. The Faith would have most of them condemned to death for their practices, and yet somehow they persist through centuries, always in secret.

Since the fall of the Satrapies, the Wastes haven’t been crossed, or those who have crossed it have failed to return. Once a great trade road spanned across the Satrapies, connecting the lands that became Theudengard with a distant place called Serica. Some of the strangest artefacts from this lost country still decorate the palaces of Theudengard, with even a few trinkets still in Ostromarka.

That’s all I’ve cobbled together so far. I think there may be Elves and Dwarves allied with Theudengard somewhere, perhaps coming from the North and South of the kingdom, or far to the west. So far, other races need not apply.