Tepest, or 'how many different ways can I spell "Inquisition" wrong?'.
This is our Salem domain. It's a decentralised largely rural sort of place living in fear of fey and witches and (to some degree) each other. This is the last domain in the Gaz range with a meaningful population, so I'll whine about the numbers one more time for tradition's sake. We have a population of 15 000 here, which is perfectly reasonable - except that it gives this rural backwater a population larger than the bustling metropolis of Dementlieu. Also, give the prominence of goblins in the description, having them comprise 1% of the population is just silly. That's 150 goblins for the entire domain, but we hear about goblin bandits and tribes and grave-robbers all the time. Bleh. Learn to count, dammit...
Geographically, we've very isolated here, which fits the insularity of the domain well. Tucked up in the forested mountains to the far north-west of Nova Vaasa, where the rivers start. Some of the less-trafficked bits of Darkon to the north, and only the dead land of Keening and the Shadow Rift as other neighbours. We have a couple of towns, Kellee near the border is a bit more cosmopolitan (only by comparison) due to being run by an Nova Vaasan expatriate, but it works as a less-forgiving introduction to the domain for PCs who need to learn the rules without ending up tied to a stake. Sharp ridges, steep ravines, and dense forests make travel slow and everywhere isolated here, which also fits well with the theme of the place. Isolated homesteads, perhaps each with a pasture or two, an orchard, or a fishing boat and some frontage on the lake, house most of the population. But it's not the worst place in the Core to live to be honest, there are certainly dangers out there but if I had to live in a rural farm cottage in Ravenloft, better it be in Tepest than somewhere like Kartakass, or heaven forbid, Verbrek. The main road here (and leading to Tepest from Nova Vaasa) is called the Timori Road annoyingly enough, despite having nothing to do with Timor whatsoever as far as I can tell.
History is in three main parts. First we have myth-cycle history, which explains how the various Celtic gods (working in shifts) created all creatures of the world in their different seasons (fey in spring, mortals in summer, undead etc in winter, miscellaneous monsters in autumn) and explains how the populace divides their own pantheon sharply into two rough categories, the gods who created humanity (Belenus mostly) who are revered, and the gods who through malice or mistake created everything else, who are distinctly second-class (which'll be a sharp shock to a follower or, say, Lugh or Daghda from Forlorn...). It's a nice division actually, and I think it works well. It'd work better if we had any actual centre of regular worship of this pantheon literally anywhere else to contrast it with, of course. Second bit of history is speculating vaguely on where the ancient ruins come from, nobody really knows and it's basically irrelevant to the modern domain. This is just word count wasted, to be honest, though there is some attempt to tie the fall of this old civilisation with witches, to help explain the modern animus against them. Then we have modern history, which is a bit more interesting. Tepest popped into existence in the Core, and as this emergence was due to the acts of the three hags being taken by the Mists, nobody human knew why. They started up trade with their neighbours in Nova Vaasa and G'Henna and became something of a trade route before G'Henna disappeared overnight and was replaced with the Shadow Rift. This caused not-insignificant economic hardship, and combined with the fey critters now filtering from the Rift (or in service to the Hags) led to the rise of the Inquisition, which is now probably the defining social feature of the domain (the secular government is fairly decentralised and seems to be some sort of nebulous mayoral system from town to town, it's the church of Belenus and the Inquisition we're supposed to be interested in here). The inquisition was started by a priest named Wyan, and drawing from the myth cycles mentioned above it blames a lot of Tepest's troubles on fey plotting (notably the rise of a brand new creepy fey domain right next door and the disappearance of a major trading party). Wyan and his folowers have had lots of success, and probably a fair few false convictions, but they make an attempt to at least follow an investigative process, and people are found not guilty and are not executed from time to time. Recently, however, one such person was Wyan's daughter who was charmed/tempted/whatever by a fey creature, an event which shook him to the core and he's stepping back to re-evaluate things. However, there's rumblings among some of the more stereotypically-Inquistorial members of the Inquisition that Wyan is going soft or getting old and it's time for new leadership and more vigorous efforts towards the goal of lots of people being set on fire.
Your party will have trouble travelling here. Clerics of mainstream gods are mostly ok if not always actually liked (except those of Hala, who is deemed to be a bit too witchy despite her clergy's hatred of hags), and bards are have a social role as long as they're well-known to be local, respected, obedient, and stay in their lane, but any sorcerers or non-human characters are considered fey, which is punishable by execution. Wizards aren't considered actual fey, just powerhungry irresponsible madmen dabbling with unholy powers that humanity was not meant to know, so ... yay? I assume warlocks would be treated the same as wizards, because 'powerhungry irresponsible madmen dabbling with unholy powers that humanity was not meant to know' is basically the dictionary definition of warlock.
Our darklords are a bit weird in that they're basically not involved in any of the main presented human conflicts in the domain at all. The three hags were attractive but evil triplet sisters who lured travellers and then murdered them for their belongings, who were then all courted and set against each other by the same callous travelling rake, killed him and ate him when they found out, and were cursed to become hags as a result. They're joint darklords of the place, and a lot of the goblins and some of the lesser fey here serve them, and the hags send their minions out to rob graces and collect macabre spell components from the executed victims of the Inquisition ... but they just don't seem to have much of a goal. They collect spell components but we're not told what those components are for, or what spells they're being used to cast, or what plans the hags have that requires those spells. There's just a lack of motivation - hags should plot, shouldn't they? Not just lurk in the woods and cackle? Their writeup says they 'hate youth and beauty' yaaaawwn, and are only otherwise motivated by a desire to eat people. Which really seems lacking ambition, for hags.
Our unreliable narrator S does not actually know how the darklord is. She can't decide between the hags, Wyan, or a possible third party (this bit is rather confusing, I get the impression she's talking about someone specific but the maps are so bad it's hard to tell the location of the forest where she believes they dwell, so I'm not sure if it's just meant to be the hags and the editing is confusing). The writeup is a bit like the Sithicus one in some ways, it's suffering a bit from post-canon syndrome. Significant chunks of text are put towards describing the aftermath of the old 2e Ravenloft modules, Servants of Darkness and The Shadow Rift, with the result that it's a bit unclear what the 'modern' PC party is meant to do here. And again, the ruthless excision of sidebars and plothooks from this last Gazetteer really don't help the situation. Wyan is actually a reasonably nuanced and well-drawn character here, chastened post his trauma in Servants of Darkness, actually considerably sympathetic and dedicated to doing his best, even though he's woefully ill-informed (he'll still resolutely kill you to death if you're an elf or a sorcerer though). I think there was a conscious effort not to go too deep into the Inqusition cliches here after the excesses of Invidia and Falkovnia. The Inquisition here actually has a point - this place IS lousy with hostile fey creatures. So the place has a tragedy-waiting-to-happen vibe, the inquisition is meant to be symbolic of good causes going bad. Like Nidalia - Wyan might not actually be an Elena Faith-Hold in waiting, but his offsider Finn certainly has the potential.
As for use in a game - there's a few ways to go here. For a one-off, the classic Tepest story would actually be the story of the Inquisition, of witch-hunts and trials and mobs and questioned innocence and fey temptation and beguilement, leading to the tension between Finn and Wyan's factions of the Inquisition coming to the fore (and maybe Wyan himself on trial as the Inquisition starts to eat its own tail). You'd probably do better running this as an all- or predominately-Tepestani PC party to be honest. The place is suspicious of strangers, and the impact of running this plot would be greater if the PCs have friends and allies on both sides (and if your foreign PC party consisting of an elf fey-pact warlock, a dwarf spellblade, and a dhampir priest of the Eternal Order shows up in such a situation, you'll succeed in uniting the warring factions of the inquisition in their eagerness to kill you). It IS weird that what seems to me as the classic Tepest story doesn't actually touch on the Darklords at all, I have to admit. The three sisters desperately need something to do here, something to plan, something to WANT (or ideally, something that they each want to keep for themselves but that can only attain when working together...). Their curse is to be ugly hags, but they seem relatively accustomed to that state, they're not seeking a way to regain their human forms (they're hags, they can magically choose to appear human if they want) and generally they don't seem overly bothered, much less tortured, by their imprisonment by the mists.
For a longer-running campaign, the intolerance of the inquisition (and of the wider community - this ain't a hostile occupying power, the inquisition consists of locals, for locals, and has wide support) really limits your options if you're not running a native party. Most parties will have to go to extraordinary lengths to avoid getting targeted, and that will likely make any visits here brief and furtive followed by fleeing before you get caught. However, it definitely has potential as a campaign starting point. It's all very cosy and local (a lot of the Mordents about it there), and most critters here are fairly low-CR. Locals can also get away with being bards etc which outsiders probably cannot, although arcane casters etc are otherwise out of luck. The bad guys will be a bit one-dimensionally limited to fey with a smattering of the increasingly ubiquitous predatory Ravenloft plant life, though goblins and the clever 'goblin creature' template can add variety. This'd naturally segue into the inquisition plot mentioned above (or possibly fleeing for one's life into Nova Vaasa and points beyond once one's fey-pact or spellcasting habit comes to light?), though the ultimate domain plot of confronting the Three Sisters is a very serious challenge. They're mid-teen CR each, can bring each other back from the dead, and all together would crush anything else in the domain beneath their warty toes with precious little effort whatsoever. In summary, Tepest is a bit of a straightjacket, but it certainly could be a fun one for a while.
Random PC generator finally gave us cleric, which i've been waiting ages for, though i was hoping it'd be in an Ezra-worshipping domain. One thing that I'm not sure about with 5e ravenloft is what they're doing with Ezra. She really is the iconic deity of the setting, but it's hard to see what existing domains suit her, and there's no new cleric subclasses included in the book. I suspect there'll be a dozen 'Mist Domain' cleric subclasses up on DMGuild approximately twelve seconds after it is legally allowed. In the meantime, maybe Peace, or even Twilight (if your DM hasn't banned it) could work for Ezra? Belenus from the celtic pantheon is an easier one, Light and Order probably (I wonder if the Celtic pantheon will make it to the 5e book or will they try to move away from real-world religion and maybe merge Belenus into the Morninglord? And what about religion in places like Har-Akir and the new Indian-inspired domain?). Anyway, today's PC is a Belenus light cleric. The intent was to make her look like someone who has regular work from day to day, but who puts on her inquisition hat, armour and clerical adornments over the top of her regular clothing when she has to. Tepest isn't rich - ornate robes for the clergy are probably not a common thing here.
Next up, a mini write up for the mini-domain of Castle Island.