Harry Potter Fan Theory: The Dementors Will Take Over The World
There's a lot of scary stuff in "Harry Potter," but the dementors might be the worst of all of them. Meant as a metaphor for depression, the dementors — cloaked magical creatures who cause crushing sadness when you're in their presence and can actually suck your soul out of your body — are incredibly dangerous, and can only be fought with the advanced Patronus Charm.
So if you can summon a Patronus, dementors are no problem, right? Not according to Redditor u/Salami__Tsunami, who wrote an extensive theory about dementors on a thread titled "Dementors will one day destroy or subjugate the world. It's inevitable." As they put it, "If you're a rational human being, the idea of dementors probably inspires some existential dread. In fact, it's inconceivable to me that they take orders from humans at all. I'm genuinely surprised that they haven't taken over the world by now."
The Redditor goes on to outline their points: dementors are far too powerful, and if wizards are outnumbered, unable to cast a Patronus, or a dementor simply sneaks up on them, their attempts at defending themselves will immediately become useless. Beyond that, they could potentially learn to use human objects and weapons, although the theory does spiral a bit out of control when the idea of a dementor driving a bulldozer comes into play.
So does this theory hold water? Let's look at some evidence from the books — but, ultimately, it does actually work.
Ultimately, dementors exist outside of human control
Throughout the "Harry Potter" books and movies, various witches and wizards operate under the belief that, at the end of the day, dementors exist within their control — specifically, under the control of the Ministry of Magic. The Ministry frequently uses dementors as a sort of security system and for what's essentially the death penalty, in that the soul-sucking "dementor's kiss" is performed on the most violent of magical prisoners.
This seems all well and good at face value, but the truth is that dementors can supersede human control when push comes to shove. At times, they do; at the beginning of "Prisoner of Azkaban," they enter the Hogwarts Express to search for a convicted wizard felon on the run, causing mass chaos amongst innocent students — really, innocent children — in the process. Then, in the book version of "Goblet of Fire," after Dumbledore questions the violent Death Eater Barty Crouch Jr., who escaped from the wizarding prison Azkaban and posed as a Hogwarts professor for a full term, dementors enter the room where he's being held and perform the kiss without permission... preventing him from giving important testimony about his time working for Voldemort and the many murders he committed for the Dark Lord. Dementors can definitely act outside of human control — and it happens alarmingly often.
Too many dementors would overpower any wizard in the end
As the original poster on that Reddit thread noted, the other huge issue is that a large number of dementors could defeat even the strongest wizard — and they're completely correct. It's noted in the books that the more dementors there are, the harder they are to fight, in that successfully casting a Patronus Charm gets more and more difficult once the number of dementors increases. This makes perfect sense; they spread doom and gloom, and in order to cast a powerful enough Patronus to drive away a dementor, a witch or wizard has to access happy, joyful memories, which gets harder as the dementors cloud their heads with crushing sadness. This happens frequently to Harry and his friends and allies in the books, and if dementors managed to band together and get, say, a million of them together at the same time, it definitely seems like defeating them would be completely impossible.
Beyond that, there's the fact that some witches and wizards have trouble casting Patronus Charms or can't do it at all. A piece of lore about the Death Eaters is that they can't cast them at all (save for Severus Snape) presumably because their souls are so corrupted, but even powerful and talented people have trouble. In the books, Hermione has constant trouble summoning a Patronus, despite the fact that she's an intensely talented witch; what if a bunch of Hermiones were overwhelmed by dementors?
There are plenty of things that threaten the wizarding world, and this "Potter" fan is right — witches and wizards should be way more concerned about dementors.