What if the people who thought they escaped Ravenloft never really did? What if instead, mental projections manifested from their thoughts and ideas reached out from Ravenloft near areas where the dimensional boundaries were weak? These thoughts could be made real by the same reality altering powers which first spawned Barovian from Strahd in the first place. These are the energies which the plane uses to shape and reform itself to accommodate all the new lost souls who get pulled in. The powers which manifest the mists, allowing the sentient pocket dimension to tap other worlds for more souls.
So the mental projection, a perfect facsimile of the character, emerges from the mists feeling they have escaped from Ravenloft! But have they? There would still be the original soul, trapped in Ravenloft. That character would emerge from the mists back in demiplane of dread. Possibly in another location. They may not even realize they were still trapped. When they figured it out, it would just seem something went wrong, and they never really escaped. What they wouldn’t know is that no one ever does.
Instead, whenever a character leaves the mists there is a chance they send out a fragment of themselves, a scion, to another reality. The first scion would presumably be sent to the character’s home plane. It would be an exact duplicate of the character and no mortal magic or science could discern otherwise. However, each new one would be different than the last and be sent to a different reality. But the more times the characters try to escape, the more scions they make. The differences would start becoming more noticeable, different backgrounds, social positions, powers, alignment, items, etc.
The Lords of Ravenloft would rarely escape the mists, if ever. These are exceptionally evil souls which the Demiplane of Dread feeds on to create new realms. If the characters were to ever run into a scion of a lord of Ravenloft it would most defiantly exist in its home reality, and would be a perfect copy of the original entity. Deviation in the scions only occurs after multiple copies.
Others, including heroes of great renown, might try escaping again and again. Eventually giving up and submitting to a life in Ravenloft, waging war with its dark pawns. Each time they tried to escape they would have created another scion of themselves, in yet another reality. All these alternates scattered among the multiverse explains so many remarkably similar characters.
For example, Fistandulus from Krynn, Elminster from Faerun, and Etienne D’Ambreville from Mystara. All three of these characters are ridiculously powerful wizards with direct relations to gods of magic, avatars, chosen ones, etc. Consider the possibility that these characters are all scions of the same archmage trying to escape Ravenloft. We know that Etienne and his entire family came through an amber mist from Averoigne, a gothic horror France. And we know that they then disappeared again with their keep Chateau D’Ambreville through the same mist, only to later reappeared with a new chateau similar but different to the previous one. What if they never really escaped Averoigne? What if Averoigne is a realm of Ravenloft (based on the fiction of Clark Ashton Smith) and each time the residents of Averoigne thought they escaped, they instead they created another duplicate? Arch-mages across the multiverse who are immortal avatars of magic.
Sometimes a character in Ravenloft dies while there are scions out there in other realities. The demi-plane would recall one of its scions, typically the lowest generation, to take the character’s place. The scion would eventually realize, if not immediately, they are back in Ravenloft. Most often with anyone who was nearby at the time. They would probably start looking to escape again, possibly succeeding in creating more scions. This constant loop serves to draw more souls into the mist for the demiplane to feed and grow.
Compare the original Ravenloft adventures for the first edition of the game to the second edition material, and the third edition material, fourth edition, fifth edition. Ravenloft keeps changing and growing, feeding on the fears of its inhabitants and shaping itself to the evils of its Lords. Keep in mind however, the Demiplane of Dread doesn’t always follows the rules and nothing here is beyond its power to overcome. Weird things can happen, and if Ravenloft has need of a situation it could create the conditions whether it follows this format or not.
I think this not only explains a lot of things, like why people who have been to Ravenloft always end up going back, but it also gives to potential to create alternate versions of characters and even run dead characters by switching alternates.
These ideas come from partly from Marvel comics, with Kang and his alternate selves, or all the alternate spider-man incarnations. Partly from Star Trek with its alternate realities and the energy ripple in Star Trek: Generations. And of course ideas developed in countless games of Ravenloft game ran by fantastic DMs, including Dan Walsh, Mike Paulhus, Rob Cast, Ron Studley, Eddy Boswell-Correa, Evan Johnson, and others.
Here is an example; In a game run by Dan Walsh, we had the chance to escape the Mists of Ravenloft. There were two portals out, but only one was real. One portal led to a grassy hill, on a sunny field, with a peaceful hamlet in the background. The other one led to a raging storm-tossed sea; in the distance was a ship which didn’t look to have much of a chance against the storm. The heroes argued about which portal to take and ended up parting ways. The ones who went through the village portal found themselves still in Ravenloft. The scene was darker on the other side, the sky was gray and the buildings were worn. The mists are cruel and deceiving. The others found that they had escaped onto a ship, but that ship would eventually make its way back to the Demiplane of Dread. Ravenloft never really lets go of you.
None of this is meant to challenge any copyrights or intellectual property. I am just a very grateful fan who loves gaming and sci-fi/fantasy. Thank you to all the original creators and to the excellent Game Masters I have had the privilege to play under.