I’m sure there is one of these buried somewhere in the 75-odd pages, but it’s likely excruciatingly old and resurrecting it for the sake of continuity just isn’t worth it.

Ok, so this started in the Harry Potter memes thread over a comic where Harry accidentally kills Ron by saying “Abra Kadabra.” Because DLP is a humor graveyard a place of thoughtful discussion it spawned a bit of talk over the killing curse and how it specifically works. The discussion boiled down to these two points:

1. According to canon, you have to really mean the curses and that “everyone in that class could have AK’d Crouch and he wouldn’t have gotten even a nosebleed.”
2. In most fanfiction, it’s treated as a bullet to the head. Hit and you’re done.

So, according to canon, the fandom interpretation is very much inaccurate, and presumably, if you are hit by someone who is capable of casting the curse, you’re dead.

That said, I’ve got a few questions myself.

• When Crouch says that the curses have to be meant, what exactly does this mean?

Specifically, does this involve meaning to kill the intended target, meaning to kill in general, or a more nebulous intent such as hate or disregard for life? I’ve seen numerous explanations in the fandom, and one of my favorites was that it wasn’t so much a desire or an intention to kill, as raw emotion. In the case of this particular piece, it was hate. For reference, this was in the Merlin arc of A Long Journey Home.

• Was the talk over a “nosebleed” simply metaphor for “you won’t hurt me” or was it specifically adressing the fact that he would be harmed, but only minimally? How exactly does the curse work?

I’ve always classified the curse as soul magic. You get hit and it rips your soul from your body and sends it onwards. The events at the end of Deathly Hallows seem to bear this out. Harry was clearly hit with a killing curse and suffered no ill effects other than unexplainable and, admittedly temporary, death.

Thoughts?

 

If we disregard the seventh book, the three Unforgivable Curses seemed to be fueled by intent.

Harry, even in his anger at Bellatrix, could not get the Cruciatus to work because you had to want to torture someone. Harry wanting her to suffer was not enough. Rowling made it seem that to use the Unforgivables, you had to seriously enjoy to cause pain and death.

This made me assume that the Killing Curse and Imperius Curses were in the same mold. To get the Killing Curse to work you had to want to cause death, not just want someone dead for a quick moment.

The Imperius Curse you had to want to bend someone to your will and like it.

I've always figured the Unforgivables were unforgivable because only depraved people could cast them.

The Seventh book changed that.

The Unforgivables were cast by all sorts of people with minimal risk. Harry managed to cast the Cruciatus just because he was angry and have it work while everyone was flinging around the Imperius Curse successfully, even without training. It showed a differnet side of the Unforgivables. Perhaps they carry such a heavy sentence because they are not that hard to cast.

By merging these two mechanics together, I would say the Killing Curse (as well as its partners) are not that hard to cast. As long as someone is in a 'dark enough' mood or situation, they could successfully cast any of the three curses. This is why they carry such a heavy penalty even though there are probably a lot darker curses out there that could do so much worse.

I do think people who end up using the Unforgivables once, become more likely to use them again. It's similar to being in a war and killing people- the first person will be the hardest but after enough times, it becomes easier and easier. This is why Voldemort defaults to the Unforgivables. They are super effective, hard to block and dodge and easy to cast. It's a triple win for a Dark Lord.

 

I thought Harry did manage to cast it in OotP, he just did a shite job of it? Compared to the only person otherwise likely to be casting that Curse on Bellatrix.

 

Weren’t aurors granted use of the Killing Curse in the previous war? Hell, presumably Moody could have used all three curses quite handily and was known to be able to or Crouch wouldn’t have done it and Dumbledore would have come down like a ton of wrinkled, grey bearded, bricks. Mad Eye was crazy, but he wasn’t a murderous psychopath.

I don’t disagree that the last book generally, uh, threw the book out when it came to the unforgivables, though.

 

We know what a soulless person looks like: a Dementor victim. Ergo the Killing curse cannot work by expelling the soul. It definitely causes bodily death, by all accounts like flicking an off switch, not just spiritual death.

 

Yeah, pretty sure he did a shit job compared to Voldemort. His curse still made her scream.
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It might be the difference between removing the soul and actually pushing it into the afterlife.

 

Well, it says on the Harry Potter wiki that :

Considering this, one could say that casting the killing curse, which classifies as "deliberately commit murder" (because the caster actually has to say the words towards the person and want them to die) actually does rip a part of the soul away from the person. Now, on the mechanics of the killing curse, the Harry Potter wiki states:

So, yes, the killing curse needs to have at least some intent behind it, and the caster needs to be skilled.

 

Someone quoted the wiki four hours ago and their still alive? Damn. This site is getting soft in its old age.

 

That's the soul of the caster, not the victim, and is true of all murder, not just the use of the Killing Curse (see the Diary horcrux, created via setting a deadly animal on a person).

 

To my mind the Killing Curse imposes the conceptual idea of 'dead' on its target. Completely circumnavigating the question of what it does with the victim's body or soul.

In real (Muggle) medicine the line between life and death is often blurred. "You're not dead until you're warm and dead" is i believe an example expression. You can kill someone with medicine and then bring them back later under certain circumstances.

With magic, and the Killing Curse in particular, I believe it is much more black and white. Since magic overrules the intricate scientific reality of nature with conceptual magical nature, the exact mechanics of the Killing Curse is rendered unimportant.

The same way it is unimportant whether the Levitation Charm should cause an equal and opposite force when used to levitate an object, it is equally unimportant in what way the Killing Curse kills someone.

To paraphrase Taure:
The Levitation Charm does not levitate objects by applying force. It lifts them up because magic says they should 'levitate' and physics can go bugger off.

The Killing Curse does not kill people by [insert method here]. It kills them because magic says the should be 'dead' and physics/medicine can go bugger off.

If you tried to revive a victim of the Killing Curse you would fail because the victim is magically enforced to be 'dead' by the spell. Not like a di-spell-able continuous effect but just a new fact of reality.

Sorry if I seemed unclear or stepped on anyone's toes. I really like to think about these kinds of things and tend to get carried away.

 

I agree with OP, it probably just blows the soul out from the body in a forceful fashion, causing them to die rather than simply go into demented mode. I think that what he meant by 'nosebleed' is that using the spell needs a certain amount of 'force' behind it, simply attempting to 'push' someone's soul out without the force of something powerful like emotions would just result in minimal damage, like a nosebleed.

 

If the killing curse causes bodily death, then how did Harry survive his trip to "King's Cross"? His soul would have returned but the body would be "off", unless you are implying that that it could be turned back "on"?

 

This is explained in DH:

Harry survived death in DH for the same reason that Voldemort did in 1981: he has an anchor tethering him to life.

Indeed, this is the only situation that makes sense. To destroy a horcrux, you must put the physical container beyond magical repair. For a living host, that means death. Note that the basilisk venom in CoS did not destroy the horcrux in Harry because he didn't die. The only way for the horcrux to be removed from Harry was for his body to die.

 

Y'know, to be honest... I legitimately hadn't recalled the solution being quite that artful. Or at least, consistent within the greater narrative.

 

I always imagined the curse to be a method of tear the threads that anchor one soul to his body or mortal realm.

Voldemort had anchors in addition so his soul never passed on.
I assume if his body wasn't destroyed he would have returned to his body, like Harry in DH.

Didn't JKR mentioned somewhere the curse origin came from exorcism or something else related in ancient Sumeria or Babylon ?

 

I’ve always wondered if the Killing curse works on other animals as well? I know Hedwig takes a Killing curse and dies, but would the situation be the same for a dragon? They are resistant to magic, but where does this resistance come from and what is it’s basis of power? Is it so strong that a Killing Curse would be ineffective?

My theory on this particular mechanic goes as follows - in a world where Avada Kedavra exists as a tool only for murder, maybe the curse only works to it’s full ability against a being with a soul? Perhaps, on a being without a soul (such as an owl), it becomes a dependence on the magical power of an animal, or the guidelines that rule an animals life? (I am hypothesizing that only humans have souls in this universe because you don’t see dementors hunting anything else and they feed on souls)

For example, I believe that a Phoenix would enter its rebirth process when hit with the Killing curse, but a dragon would simply shrug it off. The curse is not of sufficient magical power, and therefore cannot kill it. A kneazle would die. A Blast-ended Skrewt would find it’s armour plating effective, but a Killing curse would work on its unarmored underside.

I know this doesn’t follow the above conversation, but I feel like those people covered the bases quite well, so I thought it would be good to explore this mechanic of the curse. Let me know what you think.

 

Dragons are stated to have magically resistant skin. The Killing Curse is specifically said to completely bypass all magical protections. I would think it obvious that the dragon would die. I'm not sure size or might has anything to do with it. I wouldn't think a dragon is any more magically powerful than a phoenix, and Voldemort's curse in OOTP kills Fawkes. It's just a quirk of the phoenix that it is reborn when it dies - whether of old age and withering away like in COS or getting hit by the Killing Curse

 

The phoenix dying and then immediately being reborn lends a lot to Taure’s conceptual framework as opposed to my proposed mechanism.

If the soul was being torn or pushed from the body to the afterlife, the phoenix would presumably die permanently as the soul of the phoenix is what is reborn. It is always the same phoenix over and over again, and without that, Fawkes isn’t Fawkes. If it is just a bodily off switch, then it stands to reason that it would just force a phoenix into its rebirth cycle.

 

I believe a (sufficiently powerful) killing curse would kill anything. The problem then becomes "who is powerful enough to one-shot a dragon?" The power of the caster matters, as illustrated by Crouch-as-Moody's nose-bleed explanation, and the size of the target matters too (well, Hermione mentions it mattering in order to transfigure the dragon, so I'm extrapolating here to general resistance to magic).

In any case, a dragon's hide is specifically said to resist magic, and since we have another example of a creature (the Nundu) needing a hundred wizards to be stopped, I'm led to believe the hide of a creature can offer some measure of protection to the Avada.

So yes, the Avada can kill a dragon because that's what it does, but if you told me that only Dumbledore-class wizards are able to do it alone, I'd have absolutely no problem believing it. And I wouldn't question why you bother introducing a giant fire-breathing lizard only for it to be one-shot by the first schmuck it meets.

 

I see where you’re (as in @MonkeyEpoxy) coming from saying the dragon would die. However, I really struggle with that idea. If the Killing curse could kill a magically resistant beast such as a dragon, why are they feared beasts? Canon shows plenty of wizards can cast the curse, and if it worked on magically powerful beasts, why be scared of said creatures? I like the idea that only a Dumbledore-level wizard could do it successfully, so I would say that in the case of a magical animal - which does not have a soul to be pushed into an afterlife as dementors do not feed on them - it is a matter of power in the Killing Curse that determines its effectiveness against magical creature. I agree with you Goten.

In response to @pbluekan, I would say it’s tough because canon says the killing curse rips a soul from its body. However, based off of its effectiveness against creatures without a soul, it could potentially be said that the curse functions as both a tool that rips a soul from the body and works as a body-off switch. I say this based off a not-great understanding of the conversation above.