Can a dementor decide which people around it will be affected by its magic?

Question

Quoting from here and here:

From a Leaky Cauldron chat:

Samantha: Was snape the only death eater who could produce a full patronus

J.K. Rowling: Yes, because a Patronus is used against things that the Death Eaters generally generate, or fight alongside. They would not need Patronuses.

I always had the impression that just the presence of a dementor should have an effect on any human around, DE or otherwise. However, this quote makes it sound like DE's are exempt from the effect of the dementors. However, from Sirius's description in book 3, we know every prisoner in Azkaban was affected by dementors, which can further be corroborated by the fact of how much Barty Crouch, Jr. was scared of being thrown into Azkaban. Moreover, if the dementors didn't affect the DE's at all, throwing them in Azkaban wouldn't be much of a punishment either.

So,

Can dementors decide who to affect or not?

Answer 1

Probably not.

I'm going to say they probably can't decide who to affect, based on their effect on Hogwarts in HP and the Prisoner of Azkaban.

If they could be so selective, they would surely have been ordered, either by Dumbledore or the Ministry, not to harm the kids in the school. Yet there they were, coming into the grounds and even the Hogwarts Express, and the students had to be warned to be careful of them. They certainly had an effect on Harry more than once, when they should have been hunting only for Sirius Black.

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As for why the Death Eaters don't need Patronuses, maybe it's because Dementors can't have so much of an effect on evil people. Their main effect is by sucking away people's happy feelings and leaving them with bad ones. But if someone's happiest memory is of torturing Muggles, say, and all their emotions are bad ones, maybe the Dementors wouldn't have much to take away from them. That's why the Lestranges, for instance, survived Azkaban without being driven any more insane than they already were.

You say "if the dementors didn't affect the DE's at all, throwing them in Azkaban wouldn't be much of a punishment either", but prison is still a punishment. Being thrown in prison in the real (Muggle) world is a pretty strong punishment, even without evil magical prison guards that suck every happy emotion out of your body. It would be as bad as that for the Death Eaters in Azkaban, even if the Dementors had no effect on them whatsoever.

Answer 2

• We don't have canon proof that they can or cannot.

• But, they are definitely shown NOT to do so, in a situation when they presumably obviously would if they could: the scene where they guard the kangaroo-courtroom where Delores the Toad is sentencing Muggleborn in Muggle-born Registration Commission.

She has to generate a Patronus to keep the Dementors at bay from her and the Death Eaters with her.

There were more Dementors in here, casting their freezing aura over the place; they stood like faceless sentinels in the corners farthest from the high, raised platform. Here, behind a balustrade, sat Umbridge, with Yaxley on one side of her, and Hermione, quite as white-faced as Mrs. Cattermole, on the other. At the foot of the platform, a bright silver, long-haired cat prowled up and down, up and down, and Harry realized that it was there to protect the prosecutors from the despair that emanated from the Dementors: that was for the accused to feel, not the accusers.
(DH, Chapter 13, "The Muggle-Born Registration Commission")

(the cat, of course, being Umtoad's Patronus)

Answer 3

As far as the books are concerned Dementors seemed to affect everyone around them. Examples of times were if they could limit their powers they didn't.

“Dad had to go out to Azkaban one time, remember, Fred? And he said it was the worst place he’d ever been, he came back all weak and shaking. . . . They suck the happiness out of a place, dementors. Most of the prison-

Mr. Weasley a ministry employee was not excluded from the effects.

The moment he had passed the place where the Patronus cat patrolled, he felt the change in temperature: It was warm and comfortable here. The Patronus, he was sure, was Umbridge’s, and it glowed brightly because she was so happy here, in her element, upholding the twisted laws she had helped to write.

Umbridge has to cast a patronus to keep the Dementors Aura from affecting her and the others near her in the court room. This is a perfect opportunity for a Dementor to target specifically just the prisoner, however, they don't appear to be doing that.

Answer 4

Judging by the incident in the Ministry with Umbridge, seeing as how it was her Patronus keeping them at bay it is probably safe to say that they did not target specific individuals.

Answer 5

There are some mixed instances where you see dementors affect everyone and some where they can't. Because then no one would like to approach them because of recalling of horrific memories, but we do see a few instances where Ministry people or Dumbledore approached them and many instances where they affect all.

"I must go down to the dementors," said Dumbledore. I said I would inform them when our search was complete."

There was a moment when the crowd recoiled when Igor Karkoff was brought into the room along with the dementors but soon after some time, the six dementors in the Trial room didn't affect the crowd ,

But the boy was trying to fight off the dementors, even though Harry could see their cold, draining power starting to affect him. The crowd was jeering, some of them on their feet, as the woman swept out of the dungeon, and the boy continued to struggle.

But also this may be because their expression were that of anger which they couldn't suck but still the crowd wasn't put into despair or sadness.

Also persons with more horrific past are affected worse,

"It has nothing to do with weakness," said Professor Lupin sharply, as though he had read Harry's mind. "The dementors affect you worse than the others because there are horrors in your past that the others don't have."

Answer 6

I think the answer is yes, they can (to some degree).

The dementors are not portrayed as mindless animals, they can be negotiated with or ordered around, not merely compelled or driven. Dumbledore talked to them during the search for Black, The ministry orders them around (and I can't imagine Fudge being able to cast a patronus to compel them), Voldie negotiates with them, and they are swayed by his promises.

If dementors could not either lessen or direct their dread (to some degree), I can't imagine how they might have been allowed in a courtroom, or a school (even to deal with supposed criminals), or be sent secretly through the muggle world to assasinate someone the ministry would like silenced, as Umbridge did. This is complicated by the fact they often won't - they had to be forcibly stopped from attacking the 'wrong' people more than once, from targeting Harry even before Black during PoA, or the way it is suggested they used the excuse of Black to disrupt the Quidditch match, to Umbridge needing to use her patronus in DH to keep them under control.

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As for Death eaters not needing patronuses, rather than being immune, it makes more sense that there are simply other ways of dealing with them than patronuses. As seen in DH with Umbridge and PoA with the students, the dementors may choose to go after those they are supposed to leave alone if they think they can get away with it, and the Death eaters in azkaban do seem affected (so it might not be about their natures).

There have to be other ways of dealing with or controlling dementors - ministry personnel might have to deal with them yet might not be able to use a patronus well enough (which seems to take a lot of skill) continuously or at all (I can't imagine Fudge casting a patronus, yet he has no qualms ordering dementors into a school). Perhaps some kind of medallion or other artifact to lessen or stop effects, some compulsion or control spells, or something that protects or alters the emotions of an individual so dementors can't meddle enough to feed.

Harry might have not been taught those other spells because they are not for casual self-defense (compulsion would be restricted, medallions would have to be crafted beforehand, spells that meddle with emotions would be more dangerous to the user, some spells might take dark magic, etc).