Dementors will eventually play a role in a story I'm writing, and I'm trying to figure out the canon explanation for how dementors are controlled. As far as I can tell, there isn't one. We're told that they are the "natural allies" of Voldemort, and they join him after the big Azkaban breakout.

But how (and why) did the Ministry control them in the first place?

If these things are immortal and desire nothing more than to feed on human souls, what keeps them confined to Azkaban? What stops them from kissing the prisoners?

My own theory, at this point, is that there has to be some sort of artifact that attracts them and allows the wielder to control them. Perhaps Voldemort stole it when he raided Azkaban to get Bellatrix, etc.?

The question of how dementors travel is also a problem. Even if they can float, they don't seem to move very fast. So how did they get to Privet Drive in Book 5? Were they portkeyed in and out? Did they have to float all the way back to Azkaban?

Anyway, just thought I'd throw that out there. If anyone has ideas about how these things originated or how they can be destroyed, feel free to speculate on that too.

Cheers.

 

You provide the reason for their obedience there I think. In my mind they are not particularly intelligent creatures, and so they are left with two options, become like lethifolds and hunted down until there are only a few left in obscure corners of the world, or become subservient and be allowed an existence, albeit a meager one. The wizards aren't particularly concerned with learning how to destroy them the most effective spell they have found merely forces them away. However, if the dementors didn't serve a greater function then wizards would be devoted to finding them and destroying them as a threat. As it is the British Ministry of Magic saw a potential use for them as prison guard-dogs. As Xiph0 pointed out, the threat of force is highly effective.

This is why they always jump ship to Voldemort, he offers them greater scope to use their powers. So although they remain subservient they are allocated a purpose and their further existence is guaranteed.

Talking about dementors, I just watched Blue Planet the BBC documentary on the telly, and it got me thinking about how Dementors breed. In the documentary herring (I think) spawn offshore and that results in the beaches getting covered in white foamy stuff (sperm). Is that perhaps what the black mist is in DH, dementor sperm!

 

I still don't get what "threat of force" would mean to a dementor. There's a charm to drive them away, but how could you destroy one if you had to? It seems like they wouldn't give a rat's ass about a patronus charm; they'd just move on to some other target.

I guess maybe someone could have rounded them all up and placed wards on Azkaban to prevent them from escaping, but then how do you ensure their obedience? If one decides to lunch on some prisoner's soul, how would you punish it? How could you even give them orders?

There are so many holes regarding dementors that it's damn hard to come up with an all-encompassing theory about them.

 

I presume the ministry's threat of force is to use a combination of transfiguration and patronuses to drive them into some enclosed space and then seal them in. Being immortal and unkillable isn't much fun if you're locked in a box for the next thousand years.

 

What I fail to understand is how they don't overrun the wizards through breeding.

There must be a method of death (meaning they're immortal to age but not to being killed, see LotR elves) or else, eventually, sometime down the line, they're going to outnumber wizards and witches. IMO, that should have already come to pass if they've been around as long as wizards and witches.

 

They are invulnerable instead of immortal. They have a finite lifespan, but cannot be killed by anything but old age or I would presume starvation. Only way the overpopulation problem makes sense, except they still should be increasing in number on a order greater than humans.

Maybe they can kill each other and they often do over resources?

 

Perhaps the newborn Dementors are culled at birth, when they might be vulnerable.

 

Ugh. The real answer, I think, is that this is just another one of those gaping plot holes that JKR either didn't notice or didn't care about.

If immortal beings can reproduce, then Bio Plague is right and eventually they would take over the earth.

So that means it must be possible for them to die. Are we sure they're immortal, or is that just fanon?

I can already tell that I'm going to have to come up with something to "fix" canon if I use these things in my own story.

 

In CR, I had Harry give a couple of them Colombian neck-ties with the wizarding world's equivalent of a bowie knife. Lot of blood, lot of pain, and a few dead Dementors later, I've come to the conclusion that I like these plot-holes because they allow me the freedom to make my monsters as badass as I want. Don't ask Rowling to specify what she meant to do with the Dementors - we might end up with gay Dumbledore. Oh wai...

Thus the beauty of fanfiction: ambiguity leads to creativity.

 

Well I think a combination of both mine and Andromalius' culling at birth ideas works. The dementors are restrained by the threat that if they turned the Ministry and general population against them the Wizards would devote substantial resources to eliminating the whole species as a threat. They are kept safe by their having a purpose in the wizarding world. Admittedly there is no currently known way of killing the creatures but if it came to a war against them, I imagine the wizards would figure out a way to kill them.

As it is they perhaps keep themselves in check by keeping their own numbers down.

 

I've been thinking of the Patronus Charm affecting the Dementors in much the same way as iron affects the sidhe in the Dresden-verse; rather than just harming them physically, it's a true bane to them through and through.

I have no basis for that idea, but it seems to fit [in my mind, anyway].

 

Maybe the dementors are just incredibly vain, and the patronus charm leaves ugly scars when they are near it. Which is why they avoid it at all possible times, so as to leave their "beautiful" face/bodies unmarred.

..What? I don't see any better ideas...

 

Does it say in the books that Dementors are immortal?

Anyway, any reasonable method is acceptable, though an artifact to control them is boring and uninspired, not to mention somewhat cliche.

 

What I don't understand is why does the patronus charm affect them. Don't they feed off of emotions, happy, saad what ever. Isn't the charm a culmination of your happiest feelings concentrated. Or is it just a spell that needs to be cast while thinking of happy thoughts but it isn't necessarily "happines". Or did JK just make that up because its hard to think happy thoughts when around Dementers,

 

Perhaps a Patronus forces happy memories into a form dementors can't consume. As an analogy, lets say milk is a happy memory. Then Patroni are like rotten milk. Perhaps Dementors dislike the "smell" of Patroni, and therefore flee from it.

 

I'm with Grubdubdub - can someone provide the actual book quote that says that Dementors cannot be killed by wizards? I'm not saying anyone's wrong, just genuinely curious, because I always got the impression that the reason the Dementors were subservient was because a good AK or beheading spell would get rid of them, and that the use of the Patronus Charm was that it provided a happy medium between the 'kill them' option and the 'endure them defenselessly' one.

 

No, I'm pretty sure Remus said the only spell that affects them is the Patronus. However, that doesn't mean they can't die.

 

Both quotes from Prisoner of Azkaban.

"...Dementors are supposed to drain a wizard of his powers if he is left with them too long...
'You made that dementor on the train back off,' said Harry suddenly.
'There are - certain defenses one can use,' said Lupin. 'But there was only one dementor on the train. The more there are, the more difficult it becomes to resist.'"

- page 188. Reveals that Dementors can be defended against. Does not say they only can be defended against.

"...It is called the Patronus Charm.'
'How does it work?' said Harry nervously.
'Well, when it works correctly, it conjures up a Patronus,' said Lupin, 'which is a kind of anti-dementor - a guardian that acts as a shield between you and the dementor.'"

- page 257. The Patronus Charm is used to defend against the influence of Dementors. Says nowhere that it is the only spell that can do so or that can effect Dementors.

I can find no other information on the HP Lexicon that suggests Dementors are immortal. Still, even if they are, as pointed out in a recent thread here, there are varying levels of immortality: from can be killed by a stake through the heart, to will die of age, to full-blown no-limits cannot die. Given that we know they are not invulnerable or immune to magic, it seems fairly reasonable that the Killing Curse would effect them.

 

Easiest way to work with dementors is to make them intelligent, either collectively or singularly. Beings with an animal like perception of the world aren't controllable by threat of force as they will constantly test the limits of their enclosure. The two that went after Harry in OotP show that they are controllable, otherwise they would have just attacked whatever was in sight. Of course we don't know how Umbridge released them, she could have just let them out with time delayed portkeys right untop of Harry.

I'm partial to the idea that there's some intelligence behind those cloaks, enough that can be reasoned with or commanded at least. A decent theory is that they, as minor demons, can be controlled through the same spells that can control demons, doesn't matter who casts the spell. So while Voldemort stole them the ministry can order them back to Azkaban, all it needs is for one of their experts in demon control to find and order them back.

There is also no evidence that a partonus can't harm or kill a dementor, after all they flee from them so they may in fact be afraid of them. It would require the partonus actually attack the dementor though, not just get close and drive it off via its aura.