WMG / Ravenloft

The Dark Powers are the land itself.

They are not sentient, or Quasi-Sentient at best.

The Dark Powers and The Lady of Pain are both the same kind of entity.

Both the Dark Powers ad the Lady of Pain belong to the same class of entity that is perhaps as powerful as, but distinct from the deities of the multiverse. Both also seem to have absolute control over their dominions, but have no power outside of it. Well, aside from the Mists appearing in other worlds to snatch up people or lands that is.

Strahd von Zarovich isn't the cursed one in Barovia.

Rather Tatyana is. Her curse is to be re-born again and again into a life that starts out well, but always turns into a nightmare of obsession and lust at the claws of Strahd. And Barovia is cursed too, cursed to have to endure an egotistical and powerful vampire as its lord. Of course, Strahd's entirely too proud to ever admit that it isn't all about him.

• But she hasn't actually done anything wrong...unless she's the reincarnation of someone else who did something wwrong, and the Dark Powers just decided to stick her and Strahd in the same curse for some reason...
• Yeah I'm pretty sure Tatyana is just another victim of the Dark Powers' notorious indifference to the incidental suffering caused to others as a result of their torment of the darklords.

The Dark Powers aren't imprisoning the various Lords, but recruiting them.

Think about it. You have a mysterious force that's collecting the worse beings in the D&D cosmology, then grants them great power, territory and virtual immortality, but at the same time curses them with something usually related to what drove them to evil in the first place. The Lords could, in theory, redeem themselves by breaking themselves out of their vicious cycle, but are placed in a realm that seems to just reinforce their bad nature, tempting them with the possibility of everything they want, but their own falability keeps them from attaining it. Their lands becoem so evil that you find evil versions of creatures you don't find anywhere else in the D&D Cosmology. Repeat for several hundred years until the Lords inside the prison become so desperate that they will enact any plan to escape, however ill-advised. The nature of the realm also causes those Lords who are too weak to lose control of their territory, while those strong enough to hold on to power only get stronger, creating a kind of evil Darwinism.

You now have an entire pocket dimension filled with evil beings, all under the control of incredibly powerful and utterly corrupt villains, who you can potentially get to follow you by offering them their freedom and what they're looking for. You now have a collection of mega-powerful generals and lieutenants to lead a vast army of the some of the most messed up supernatural forces available, and many of whom will fight for you just so that they don't have to stay in Ravenloft.

The Dark Powers are Gothic theatre fanatics, and Ravenloft is their stage.

Think about it; Ravenloft is officially described by everyone as the "Gothic Horror Fantasy" world for Dungeons & Dragons. Each different domain tells a different kind of Gothic Horror tale, but all stem from the same basic morals, attitudes, etc. Reality itself bends to favor Gothic Horror — magic being less powerful, darkness being stronger, etcetera. The Dark Powers are powerful entities who are addicted to Gothic theatre, and have created the entire Demiplane to sate their hunger. This is why they pick their villains so precisely — The Multiverse is full of evil people, but the Dark Powers only take those with either the most "interesting stories" or who show the greatest potential for such. It's why, despite being filled with monsters, in many ways the Demiplane is actually a nice world — the hope makes the despair and terror more piquant, and gives heroes a reason to fight the darkness. It's why the Darklords are given power, but tormented; the torment makes them amusing to the Dark Powers, but the power is their way of showing their appreciation. It's why the domain boundaries exist for Darklords and victims alike; it's no fun if the "playthings" run away in the middle of the show, and too confusing if Darklords can interact with each other freely — imagine two plays simultaneously running into each other. It just gets into a big mess.

The Dark Powers are really the goddess Ezra

The Lawful Neutral deity Ezra is unique to Ravenloft, and grants special powers controlling the Mists. When one considers that Ravenloft is essentially a place of imprisonment and punishment for the Darklords that rule the Domains, it makes perfect sense that a Lawful Neutral power would be in charge of running such an operation, especially since good-aligned people do get caught up in and generally have to suffer as part of it. In 2E, Ezra's faith was divided into four different sub-faiths reflecting Lawful Neutral, Lawful Good, Lawful Evil and True Neutral aspects/interpretations of the goddess. This four-way split actually matches the seemingly contradictory behavior of the Dark Powers. The Lawful Neutral aspect is the judge and jailor. The Lawful Good aspect is the one that punishes the Darklords for their evil and sometimes helps innocents within the Demiplane. The Lawful Evil aspect is the architect of a world organized into neat little pockets of evil. The True Neutral aspect represents the dispassionate observation of how all the beings in Ravenloft interact. Collectively these aspects could create the impression of a plurality of Dark Powers, when in reality it is a single fourfold deity.

The Dark Powers are Game Masters

All prequisites are met. Nuknown, even presumed entities, who are greatly capable to influence the Land, possibly empower divine magic users, and so on.

The Dark Powers are Cenobites

They revel in suffering, put transgressors through unimaginable torment, and justice doesn't appear to be their chief goal, given their utter disregard for how their curses hurt innocents. I presume they're a school of Cenobites with slightly more reserved sensibilities, since their tortures are more psychological and less visceral.

The Dark Powers are the crows and ravens.

Something very strange is going on with corvids in Ravenloft. Those that aren't being magically controlled act as almost archetypal observers, and were-ravens are the only kind of lycanthrope in the Mists that isn't evil. What they're observing is their own handiwork.

All the Material worlds of D&D are part of Ravenloft, with each of them possessing its own Darklord.

It's just a question of scale. Places like Eberron, Greyhawk and Forgotten realms might simply have a vastly more powerful Darklords and the sizes, the complexity and the Stability of those worlds simply reflect that. The Domains of the Ravenloft Core are smaller and more unstable simply because their Darklords are not powerful enough to allow for their realms to reach their full might and become complete worlds in their own right. This might also explain why the Dark Powers corrupt everyone in such a blatant manner. In a more established world the corrupting effect of using Evil or Necromancy spells is slower and more subtle. Maybe the final goal of Dark Powers is to develop one or more of their domains into a full world like other D&D settings, but none of the existing candidates so far have been capable of bringing their Realms to that level. Azalin or Strahd might eventually accomplish that in a few millenia. Maybe each D&D world is an entity all on its own and Dark Powers are simply their offspring trying to grow and mature.

The Lady of Ravens Has a Name

Everything about her is defined by ravens, in a Gothic Horror setting. She's Lenore.

Cyre was pulled to the Demiplane of Dread

A common fan-theory (and one also posted on Eberron's WMG page) about the Mourning that destroyed the nation of Cyre was actually the Dark Powers finding a good Darklord there and yoinking it and its people to Ravenloft. While the Mourning is one of Eberron's official up-to-the-DM mysteries, the Ravenloft explanation fits well (and provides a good excuse to have something from Eberron in Ravenloft):

• One of the creepy things about the Mourning was that it was clearly the work of an intelligent actor, as it stopped exactly at Cyre's political borders as they were that day. The Dark Powers clearly count, and the backstories of multiple canonical domains show that they will pull entire kingdoms into the mist if the Darklord-to-be ruled that nation beforehand.
• The border of the Mournland is a wall of dead-gray mist, which in 4e supernaturally drains creatures of hope. Mist is highly associated with Ravenloft.
• Cyre had a prime Darklord candidate in Dannel ir'Wynarn, whose insistence on conquering the continent and reclaiming Galifar's crown was the only thing keeping the Last War going.
• There is a canon example of a country taken to Ravenloft and leaving ruins behind: Kalidnay, from Athas, and the descriptions of Kalidnay's ruins does seem to match the ruins of the Mournland. While the signature magical properties of the Mournland are absent from Kalidnay, the accounts describing Kalidnay are all centuries after the fact, while the Mournland is pretty new- perhaps, after a while, the Mournland will fade and leave only the ruins of Cyre.

Ravenloft: Any number of popular franchises are actually Domains of Dread outside the Core

• Many franchises in popular culture have a very Ravenloft-like setting. The story may happen in a small area with very limited geography, possibly with only one major town/city/village, like the classic small kingdom of a fairy tale. The are has one major villain, who is the major source of everything wrong with the place, like Ursula in the little Mermaid. Villains are usually deranged and obsessed, like in A Series of Unfortunate Events all villains are arsonists obsessed with gathering fortunes. The events within the story are heavily slanted around some central theme, like in the Series of Unfortunate Events various groups fall apart in schisms, which breed schemes, grudges and lay the groundwork for new secret organizations to combat in the shadows, and nobody knows who in on what side. Also the villain of the story is nigh impossible to get rid of or reoccurring, like Friday the 13th. Characters could be struggling against fate, destiny or something similar like in Escaflowne.
• Possible franchises for Domains of Dread:
  • The Ring
  • Coraline
  • Halloween
  • Nightmare on Elm street
  • Jumanji
  • Friday the 13th
  • A series of unfortunate events
  • Dark city
  • any number of Grimm fairy tales
  • any number of classic Disney movies.
  • Ju-on
  • Castlevania
  • Megaman
  • Super mario
  • Escaflowne
  • Trigun
  • Thief-games
  • Wayward Pines
  • Dead By Daylight
  • Innistrad
  • Praedor
  • Alice in Wonderland
  • Sin City
  • Peter Pan
  • Friday the 13th - the series
  • Wizard of Oz
  • Hatchet
  • Night of the demons
  • Jabberwocky
  • Prince of darkness
  • Mirrors
  • Scream
  • Silent Hill
  • The Descent
  • Wind Chill
  • Wrong Turn
  • Triangle
  • In The Mouth Of Madness
  • Evil dead
  • From Dusk till Dawn

Strahd is aware of his Joker Immunity and takes advantage of it.

• Strahd von Zarovich acts the way he does, because he knows that his eternal existence depends on him acting like a legendary villain everyone loves to hate. Periodically, small bands of vagabonds called "adventurers" enter his realm to take assignments, kill monsters, take treasures and just goof off, until they finally are ready to come to kill him. These adventurers claim to be denizens of other worlds Strahd has heard of before, but their actions reveal these identities to be thinly veiled disguises. He has deduced that in reality, these adventurers are nothing more than puppets for cosmic entities possessing them called "Players". The Players are just enjoying themselves through these meat puppets. Strahd concludes that as long as he plays to the expectations of these Players and acts the role of a memorable Big Bad, even if they kill him, he and Barovia will always cycle back to square one and give him a new chance at unlife to attain Tatyana while another group of Players hinders him.

The Demiplane of Dread was originally created by mortals, not the Dark Powers

• It was originally an attempt to create Heaven gone horribly wrong. The mortal lords and mages were trying to create a plane where all their dreams would come true, a paradise under their complete control. Since everyone has different goals and desires, this demiplane could be partitioned off so no one's fantasy would intrude upon the others. But like a certain other story, when they entered their new playground, their fears and jealousies and petty thoughts consumed them, as the Demiplane shaped itself to accommodate their dark sides. It was only later that the Dark Powers, whatever they are, came across Ravenloft. More experienced with shaping such powerful magics, they provided order and structure, turning the Demiplane of Dread into a sort of prison menagerie that could tailor itself to its guests, providing appropriate themed punishment.