What does happen in a land with low population density and centuries of isolation?
Nothing is settled; everything is up for grabs
OK, so it turns out there aren’t enough people in Ravenland for you to be able to rob a tomb, sell the golden artifact to a merchant, buy a better sword and armour from another merchant and spend your spare change on a nice meal in an inn. But there’s stuff you can encounter that you won’t get in a standard extruded fantasy world.
Variety of rulership models
Your standard fantasy world is a cod-Medieval world that looks an awful lot like 14th-century Europe, which means feudalism. You’ve got a hierarchy of rulership from the Emperor or King at the top, through Dukes, Counts and Barons all the way down to knights. The only thing that really changes is the size of the crown and the decadence of the court. Maybe if it’s set a century or so later there are powerful merchants as well, but that’s about it.
After 260-odd years of deprivation and isolation, the political model in a Ravenland settlement could be almost anything.
Maybe decisions are taken in a collegiate manner, by consensus, and it’s not at all clear to an outsider who the people in charge actually are? (Yes, there’s someone leading prayers to Wail, but someone else does the ritual of Clay, and both of them have cows to milk and fields to tend to.) Or maybe there’s one leader, who rules by force of personality and persuasion; unless they divide and confuse everyone instead, gaslighting their potential opponents; or rule by fear, backed by a few trusty henchmen; or act more like a leader of a sect, promising that salvation is just around the corner, which works fine until a solar eclipse happens and everybody loses their nerve.
Maybe the settlement used to be a place of learning, and the locals still pantomime copying books and reading scripture, but everyone’s forgotten how to read and nobody even understands what they’ve lost? There’s all sorts of ways institutions could have… rotted over time, especially if the locals are humans or something similarly short-lived. Conversely, it’s possible for an Elvenspring village to be run by people who were alive before the blood mist, and who cling to a belief that things will sort themselves out eventually. (There haven’t been visitors for centuries, but children still learn to read and write from the old ledgers that talk about trade of grain, beer, wine, cloth, iron and wood up- and down-river.)
The random tables of quirks in the Gamemaster’s guide are a good start, but IMO they don’t go far enough. Every settlement should be really, really weird. They’ve been isolated for 260 years. Why shouldn’t they be?
Extreme wilderness
The land is really, really empty. There haven’t been people wandering around to any significant degree for 200-odd years. Pretty much all of the land once you get a kilometre or so from a settlement is pristine wilderness again, like the finest David Attenborough documentary, except that there’s no voiceover to tell you what any of these things are, and if you can eat them. The animals aren’t afraid of people; not even if they’re not actually demons.
You’ve got vast flocks of passenger pigeons. Herds of horses and bison. A random encounter in grasslands could just be: there is a vast herd of bison between you and where you want to be. As far as the eye can see. How are you going to get them to move?
One answer might be: you can’t get them to move, but maybe this pack of wolves might. Or maybe the gryphons, or wyverns. Certainly by the time the dragon turns up the bison are in serious trouble, although the good news is that they might just stampede you rather than actively seeking you out.
Personal agency
In a world where everything is mapped and understood, PC groups are unlikely to have any impact on the world. The Forgotten Realms are pretty well-remembered by this point, and the typical way of toppling a centuries-old realm is to get lucky and tap into somebody else’s centuries-old plot, because you certainly can’t defeat a massed army and its supporting polity with just the five of you.
But in Ravenland, what are the odds that there’s even another PC group in the world at this current time? Sure, there might be a dozen or two people with the exceptional drive and ambition to go out into the world, fight monsters, battle terrible people and turn themselves into a political force to be reckoned with. But how many of these live close enough to each other to band together effectively?
How did the PCs manage to e.g. find Stanengist? The answer might be that nobody else was looking. Ordinary people were just happy that bloodlings were no longer threatening to kill them in their beds, and could relax into the more comforting everyday terror of worrying whether they were going to die of starvation this year or the next instead. The occasional exceptional person might be too young, or too old, or they’ve got a friend who’s good at some parts of the adventuring lifestyle but they really need more to make a significant difference, and there’s nobody. And of course the people who might have spare bodies to go looking for magical artifacts, like Zytera, Kartorda or Zertorme, have their own realms to rule and problems arising from the blood mist having gone away and suddenly far too many people are asking awkward questions.
OK, so this isn’t a world where vast armies collide and impossible feats of magic are hurled from rival wizard towers. But if a major stronghold like e.g. Haggler’s House only has 100-odd soldiers protecting it, a dedicated PC group could seriously dent its numbers by judicious guerilla tactics, maybe as a precursor to organising a popular uprising, and during the distraction the PCs sneak in and get their revenge against a snide NPC who’s been annoying them for sessions now, before wiping a smile off both of Kartorda’s faces.