Buffy the Vampire Slayer has amassed many fan theories about characters and plot lines alike; one suggests that Dawn's entrance in season 5 was partially ushered in by Dracula.
Joss Whedon's cult classic television show ran for seven seasons from 1997-2003 and has a dedicated fan following almost twenty years after going off the air. The adventures of Buffy and her friends, collectively known as the Scooby Gang, taught audiences about growing up, life, love, loss, and even sparked more philosophical conversations about religion and spirituality. All of this was done cleverly under the guise of a "monster of the week" style format, which was popularized by shows like The X-Files and has continued through modern shows like Supernatural. Dawn (Michelle Trachtenberg), Buffy's little sister, was a much maligned aspect of the series, and made her first appearance in season 5. Though she came as a surprise to fans, as there was no greater mention of Buffy having a sister before Dawn arrived, her first appearance was carefully foreshadowed seasons prior by Whedon and the show's writers. Season 5 not only introduced the character, but set Buffy up to make the ultimate sacrifice: her life to save both her sister and the world.
While Buffy died before, in season 1, it was short-lived; Buffy's death in the season 5 finale, "The Gift", was originally meant to end the series, but Willow (Alyson Hannigan) brought her back to life in the two-part season 6 premiere. In season 5, it's revealed that Dawn is not actually a human, nor Buffy's sister, but a mystical key that was given human shape by the Order of Dagon, a group of monks who were attempting to hide the key from Glorificus, an evil goddess from a Hell dimension. Dawn shares Buffy's blood, but how did the monks get the blood in the first place? One theory draws an interesting conclusion.
Buffy The Vampire Slayer: Did Dracula Help Create Dawn?
In season 5, episode 1, "Buffy vs. Dracula", Buffy comes face to face with the Count himself. Though his appearance certainly seemed out of place, as there was no prior indication that he was anything more than myth, a fan theory on Reddit posits that Dracula might have been sent by the Order of Dagon to obtain Buffy's blood. In doing so, they would be able to use said blood to give the key human form (Dawn). While the timeline is fast - Dawn shows up in the same episode - it's not necessarily impossible. Magic works in strange ways in the Buffyverse; the monks potentially could have the sort of immense power to conjure up a person in a matter of hours.
However, where the theory falls apart a little is considering how the monks messed with everyone's memories to include Dawn. Some have theorized that it was this magic relating to memory alteration that may have caused Joyce's brain tumor, which ultimately led to her tragic, sudden death from an aneurysm. Spike and Anya both remember Dracula from past meetings, so either they weren't as directly affected as the others, or only relatively short-term memory was affected from those who were newer to the gang. Buffy and her mother would have required the most magic in regard to memory, so this doesn't completely poke a hole in the theory.
Many have said that Dracula's appearance in the season 5 premiere seemed random and out of place, especially for such a powerful, well-known character; if nothing else, this Buffy the Vampire Slayer fan theory gives a little more reasoning behind Dracula's appearance and adds some significance to something that seemed otherwise entirely random.