Let me explain.
It is generally well known that the Ravenloft setting pulls people from other realms into the Land of the Mists. The setting has characters from other settings such as Krynn, Faerun, Athas, and Oerth. The mists of Ravenloft can also abscond with characters from Gothic Earth--a setting that where all the elements of the Victorian Gothic are real rather than fictional. In fact, Ravenloft has a domain--Odiare--that was stolen from Gothic Earth's Italy.
And that's where Dracula comes in.
Dracula is one of the great evils of the Gothic Earth setting. If the mists can incorporate Odiare into its patchwork of horrors, there's no reason why it could not also pull Dracula from Gothic Earth's Transylvania and insert him in Ravenloft as the dark lord of a new domain. Of course, if that were to happen, it's only a matter of time until Dracula and Strahd square off to determine who is the true lord of the undead. What a horrible war for player characters to find themselves in the middle of...