Intricacies of the Killing Curse
The Killing Curse in Harry Potter seems to be a very simple piece of magic. You zap something with it, and it kills it (if it's alive) or blows a hole in it (if it isn't). Nothing to see here; move along please.
Um, nope. Nothing is that simple in Potter. And this curse is obviously not simple. We get three different versions of it, as well as a pretty serious (at first glance) issue that appears to contradict how the curse is demonstrated to work. It is my position that there is no contradiction, and every strange moment can be explained.
Why Not AK the You-Know-Whats?
(Or, How It Ought To Work)
Well, it had to happen. After the release of The Deathly Hallows, I was going through the books with a fine-toothed comb, looking for inconsistencies and unanswered questions because I'm a perfectionist and that's how I roll. All the while, ignoring a big, whopping one that was staring me in the face.
Upon reflection, I'm not so sure that it's an actual inconsistency so much as an unexplained bit of magic.
The issue is this: If Avada Kedavra got rid of the soul fragment within Harry (without even killing him), why wasn't the Killing Curse used on all the Horcruxes?
I know, I know—the narrative that Rowling chose required there to be a "quest" for the sword. It required that the Trio have something to barter with to enlist Griphook's aid. (It did not require the Silver Doe scene to prove Snape's loyalty, however.) But in a book universe with set rules, the author can't just say "I'm doing this because the story requires it." There must be a reason within that universe why a particular narrative occurs.
Well, okay. We have a story in which the AK works on a living Horcrux to destroy the "alien" soul fragment. However, it apparently doesn't work on object Horcruxes. And I don't buy that "the kids would never use it." Bull hockey. I really do think that the Trio would have deigned to use it, during those long months with the malevolent Locket and no clue how to get rid of it—if the Killing Curse were a known way to exorcise one. Destroying a Horcrux is not the same thing as killing a person (well, usually). The fact that it was never even suggested tells me that we can accept that the AK, if used on an object Horcrux, does not work.
Why not? How does the AK actually operate when it acts as it ought?
I will be explaining in a bit that the specific AK used at Godric's Hollow hit the wall because it bounced off Harry and Voldemort. I'll also explain how the Forbidden Forest AK operated. These are special cases. Your garden-variety Killing Curse is simpler. I think the source of the fan confusion on this issue ("Why didn't they AK the Horcruxes") is a misunderstanding of how the curse acts. I've read some posts in the Leaky Lounge suggesting that people think the curse is something that expels souls from bodies.
Well, no. Not exactly. I think that if someone were to hit Barty Crouch Jr. with it, he'd die just as surely as any of the curse victims we've read about. What we have here requires us to take a look at the nebulous concept of "life force."
Life force is separate from soul. It's the intangible force that keeps an organism alive of its own accord. The Inferi are reanimated by magic, but they have no life force, and their "life" is dependent upon the will of the wizard that created them. I doubt that they could be stopped by the Killing Curse, for that matter. The Killing Curse terminates the life force of an organism. If there is a soul inhabiting the body, it departs naturally—and instantly, making it impossible to revive the body.
The normal process of death is for the life force to be shut down first, and for the soul to depart. Those unfortunates who have been Kissed have had this process of death reversed, but the Killing Curse would still work on them. The fact of near-death experiences (even in the real world, of course—and there's no reason they can't occur in the Potterverse) suggests that a soul can depart the body, and the body can even be clinically dead, but if that soul were to return, the life force of the body can restart itself. The Killing Curse apparently operates in such a way to make it impossible for the life force to be restarted—usually. I think that the curse must somehow check to ensure that there is no soul matched to what it hit before it ends itself, but it doesn't directly cast out a soul. It terminates the life of the victim.
I think that a Horcrux disrupts the process, because the soul of the intended AK victim doesn't leave, and the curse "senses" that it failed. It can detect that its victim's soul is still on this side of the Veil, and not in the form of a ghost. I'll elaborate further on this in the next section.
None of this happens, of course, if the AK hits an inanimate object. In that case, the curse becomes pure energy, and blasts apart whatever it hits. Despite it being "Dark magic," there's a strong hint that these objects can be physically repaired. The Potters' house was deliberately left ruined, after all. In all probability, the AK would simply "blow up" a Horcrux. There's no life force to terminate. Although there is a soul there—or part of one—it reads as an inanimate object to the curse. And we know that it could repair itself then.
Here's a diagram I made to explain this graphically:
Well, OK. How did it work on Harry, then? The Horcrux could not have been Harry's soul. There is absolutely nothing to suggest that anything other than a solid, physical object could be one. It had to have been his body. Surely a corpse could be a Horcrux just like anything else. Why didn't that AK kill Harry, but leave the body intact as a container of Voldemort's soul?
These You-Know-Whats were immediately deemed unnatural and wrong, but only upon reflection do we realize just how much. This is an unpleasant line of inquiry, but I'm forced to conclude that, if the Horcrux is made properly, and if it was made from a living thing, that being's corpse would remain a Horcrux long after the natural death of the organism itself. There is no reason why it wouldn't. We KNOW that bodies can be prevented from decaying fully, by means of Inferius reanimation spells. I can see nothing to suggest that a similar process couldn't be used to keep a corpse functional as a Horcrux.
Which means, incidentally, that Nagini had to be poisoned with basilisk venom or burned with Fiendfyre. An AK wouldn't have done the trick. She was made properly, with the actual Horcrux spell. A spell that we still don't have. We don't know, even now, all that it does. We do know that it's very powerful, and makes the item capable of repairing damage to itself. Hermione's book tells us so, albeit indirectly.
Harry, of course, was accidental. That spell was never cast on him. He received no sort of self-regenerative protection. He was a Horcrux by definition only, and a defective one at that. The bit of soul within him was dependent on his biological processes, his life force. And when that Killing Curse hit him, it obliterated the piece of Voldemort, completely annihilating it like any fragment would be annihilated in the destruction of its housing.
Godric's Hollow: Where the Body Went
Because it is intimately related to the curse, I need to touch on the issue of Voldemort's first disappearance. As we now know, VaporMort, the disembodied seventh part of Voldemort, was pulled from his body when the rebounding Avada Kedavra curse struck him. One really strange thing about that is that Voldemort's body disappeared. The investigators found no body, and I would imagine no explosions of gore and blood, as would have been discovered if the curse had simply blown him up. If there had been a body or remains, there would be none of the mystery about his fate that there was, according to Hagrid in the first book. He would have been presumed dead by all—except, I imagine, Dumbledore, who I think knew that Horcruxes were in the picture long before Harry's second year.
In DH we got, at long last, an account of the night from Voldemort's point of view. I quote:
And then he broke: He was nothing, nothing but pain and terror, and he must hide himself, not here in the rubble of the ruined house, where the child was trapped and screaming, but far away... far away....
'No,' he moaned.
The snake rustled on the filthy, cluttered floor, and he had killed the boy, and yet he was the boy...." (p. 345, DH/USA)
First, I'd like to point out that the house wasn't "rubble," whatever Voldemort perceived at this point. According to a description of it that we got not too much earlier in the same book, part of the house on one side was blasted away. The house itself didn't blow up, as many people, myself included, had assumed. Now that this is established, it eliminates the need to explain why this AK had "exploded a house," when no such thing had happened before. It didn't this time either, and the damage that was done was perfectly consistent with the type of destruction that we've seen the AK do before when it hits an inanimate object. So that's that.
However, this opens up a whole other can of worms. Why did the AK hit the house in the first place? How could it hit the house? Supposedly it had hit Voldemort himself, and that was why he lost his body. There is not a single instance in the entire series where a Killing Curse finds a target, kills the target, and proceeds to blast apart whatever was behind that individual. The fact that the curse hit the wall, and did the sort of damage to it that a misaimed AK would be expected to do to a solid object, led me to reevaluate whether Voldemort was actually hit with that curse in the first place.
I'm going out on a limb with this, and it may well be shot out from under me in the future, but for now, I am postulating that the Avada Kedavra did not cause Voldemort's body to disappear. That curse apparently did hit him, but it didn't "take," or it would not have kept going and hit the house. Period.
We actually got a clue about this in Goblet of Fire. In the Priori Incantatem sequence, there is no echo of the curse that failed to kill Harry Potter. If Voldemort's body had been the final target for it, then it should have reproduced an echo of himself. We got nothing. At the time, and for the next several years, it was assumed that this was an error. I don't think so. I think it was a clue. We have no reason to believe that failed curses show up in Priori Incantatem, do we? If its final target was the wall, that was logged as a dud AK. The curse is designed for a living target. There would be no shadowy figure to reappear if the curse's "victim" was logged as an inanimate object.
Yes, the curse hit Voldemort. He says so himself in book four, when he tells the Death Eaters that it "rebounded upon him." But it didn't stop there. It kept going and landed on the house, and Voldemort's body disappeared, leaving a part of his soul behind.
Voldemort's memory of the event in DH was that "he broke." As we know, that happened quite literally, with the part of his soul that was damaged by his murderous intent toward Harry breaking off the main soul, and lodging itself in Harry's body. From Voldemort's point of view, I imagine he means that his soul broke from his body. This allows me to form a tentative hypothesis about what happens when a wizard with a Horcrux is hit with the AK: The curse shuts off the life force and causes the remnant of their soul to depart from the body, but because the curse didn't kill anyone, it does not terminate itself as it usually would.
In fact, it seems that when a wizard with a Horcrux is hit by the AK, it completely destabilizes the curse. Small wonder, really. It's actually the same principle behind what happened with Harry. The AK isn't supposed to hit more than one thing, ever. If it hits an object rather than a living being, it doesn't keep going until it does find something living. It blasts its target apart and terminates. Lily Potter managed to get Voldemort's curse to rebound. It's likely that it rebounded upon Voldemort because he had "breached the contract" that he and Lily inadvertently made of her life instead of Harry's, but the actual reason why it stayed alive rather than dissolving upon hitting her magical protection was because it had not found a terminus point. When it hit Voldemort, it pulled his soul from his body and shut down the life of the body (and Voldemort's soul shattered from it), but the curse didn't register this as a legitimate termination either, so it kept going. By the time it hit the wall, it had effectively bounced off two people. No wonder the entire wall was blasted open.
The curse is designed to kill a living body. When it finds such a target, it will indeed shut down the body's life force unless there is additional protection of the variety that Lily Potter provided.
But when the intended victim has a Horcrux, the person's soul is blocked from passage through the Veil, and is able to repossess the body and start up the life force again. It's the same idea as a near-death experience in our world. The body is clinically dead, if you will, but is not brain dead until it has been uninhabited for long enough for its organs to be deprived of oxygen and deteriorate. The AK detects that its target's soul is still alive, and the curse didn't work as it should have, so the curse does not terminate itself, but keeps going until it hits something that can terminate it. Needless to say, this sounds incredibly dangerous for anyone who might be in the vicinity of a fragmented Dark wizard who's engaged in a duel to the death.
I think that if Voldemort had wanted to, he could have repossessed his body. Note, though, that this is only possible if the body is able to sustain life. The Killing Curse causes no harm to the body. It would not have worked if Voldemort had been set on fire, for instance. So what happened to the body, then?
The body disappeared after Voldemort decided that he had to flee. And, again, we got a clue about it, this time in Order of the Phoenix. In the Atrium scene, when Voldemort possesses Harry, his body disappears. It vanishes. It isn't Disillusioned, because the water that had been around it splashes to the floor. It's gone. What's more, as soon as Voldemort abandons his body, Dumbledore knows what is about to happen. It appears that we can establish that when a wizard is possessing someone, or when they voluntarily abandon their body, their body vanishes, and only reappears after the possession is over.
So Voldemort's body disappeared that night in 1981 because he abandoned it, and by the time he was past his "pain beyond pain," it was too late to return. The Killing Curse had seen to that, shutting down the life processes, and although it was vanished, the body had been dead for too long to return to it. I'm not entirely sure why a dead body didn't reappear when Voldemort realized what had happened, but he may not have attempted to repossess his old body, knowing that the clock had run out on it when he stayed gone, and it would be pointless.
That Bloody Chapter, or, the Forbidden Forest Snafu
There seems to be a fair amount of confusion in fandom about the mechanics of how Harry survived the second hit with Voldemort's AK. I shared this confusion until, rather belatedly, it all fell into place. What happened was that Voldemort inadvertently made himself into a quasi-Horcrux for Harry.
When a wizard creates a Horcrux, there is a Source—what is left of the original soul, which contains the wizard's seat of consciousness. The Horcrux serves to protect the Source from passing beyond the veil of death, because it apparently violates a metaphysical law for parts of the same soul to exist both in the world and beyond it. The Horcrux itself, or rather the soul fragment stored therein, is not protected by the existence of its Source, and will be completely annihilated if its housing is rendered unfit for it.
What Voldemort did when he took Harry's blood was to create a sort of Horcrux for Harry's body. Harry's body is the Source, and as long as its "Horcrux"—Voldemort's new body—exists, Harry can choose to remain alive. He doesn't have to, it seems, based on his conversation with Albus Dumbledore, but he can. I suspect that there are other conditions to his survival as well. I think his intended killer must be Voldemort, and I think that he himself must have gone in expecting to die. But, given the right conditions, he does get a choice. One thing that was immediately clear is that the metaphysical limbo "King's Cross" is the point at which dead wizards get a choice about whether to "go back" or "go on." In most cases, going back would mean returning to earth in the form of a ghost, because their bodies would be dead. Harry's choice entailed true life because Voldemort's body, in Dumbledore's words, tethered its Source to life. Dumbledore realized this in Goblet of Fire when Harry described Voldemort's resurrection, and this accounts for the "gleam of triumph" in his eyes: He believed, for the first time in at least two years, that the Boy Who Lived had a chance to get out of this alive.
It seemed to me that Dumbledore was leaving an awful lot to chance by having Snape send Harry to his death. He does seem to have known that Harry could survive, but if Harry did survive, then what about after he returned to life? I had been assuming that once Harry returned after destroying the last Horcrux within himself, Voldemort would come back as well, and he'd have to be taken out. There was no way for Albus to know what Death Eater would be chosen to check Harry for signs of life. It happened to be Narcissa Malfoy, who had her own axe to grind by then, but it could just as easily have been Bellatrix or any Death Eater who wouldn't lie to Voldemort. The risk seemed unacceptably high, especially for Albus to tell Severus that Harry's death "would truly mean the end of Voldemort." Oh no it wouldn't, not necessarily. Albus may have been hoping for Snape to remain alive and be the Dark Lord's favored follower, and for him to be chosen to do the inspection, but even that couldn't be left to chance.
It occurs belatedly to me that no, Albus didn't intend to leave anything to chance. If all had gone according to plan, then Harry would have taken Voldemort down with him as soon as the Killing Curse hit Harry's body. Voldemort was supposed to die with that curse. The "bodycrux" doesn't work exactly like a Horcrux, you see; if the Source is attacked by its "satellite," then the satellite will kill itself by destroying its source, even if the soul belonging to the Source chooses to return to its body. J. K. Rowling has stated that the flayed thing in the King's Cross chapter of The Deathly Hallows was not the piece of Voldemort's soul that had inhabited Harry, but was in fact Voldemort himself, and that is why he was unconscious. The only reason why Voldemort got to return was because of Nagini. That went against Albus's plan; the snake was supposed to have been dead when Harry handed himself over. It is only by sheer luck, the fact that Narcissa examined him and lied for him, that Harry truly survived.
It begs the question of what would have happened if Harry had chosen to die. I find myself suspecting, since Voldemort remained knocked out until Harry returned to his body, that Voldemort would have become VaporMort once again, his body killed by his action. Perhaps he could have repossessed it; perhaps not. Ultimately this is nothing but idle speculation, though.
When Voldemort cast that curse, here's what should have happened if Albus's plan had worked out and Nagini had already been dead. The curse would have destroyed the last Horcrux, which was not tethered to anything, but was open and vulnerable to annihilation. It would have catapulted Harry's soul into the King's Cross netherworld. Voldemort's would have been forcibly dragged there as well, since he had attacked the Source of his body's life. Since Harry had the choice to return, presumably he would have. Voldemort, however, would not have had this choice, having just destroyed the last thing anchoring a part of him to earth. He would have died.
What actually happened was that the Horcrux was destroyed, and the two souls were sent to King's Cross, but Voldemort could not stay dead because the soul fragment within the snake anchored him to earth.
Small wonder that Dumbledore wanted Harry to go back. If Harry had decided to pass on, I wonder if anyone would have made an attempt on Voldemort's life even after Neville killed the snake. Ron or Hermione might have; they alone knew what the snake's death meant. But it doesn't mean they would have succeeded. And one fatal flaw of most of the Order of the Phoenix is their unwillingness to use the Killing Curse. Molly Weasley almost certainly used it against Bellatrix, but other than that, the only White Hat that we have seen use it is Severus Snape. And, most likely, Albus himself, since his greatest fear was that he had cast the curse that killed his sister.
I would not be a bit surprised, in fact, if Albus's backup plan (in case Harry died while a Horcrux still existed) had been for Snape to do that.
Fortunate, indeed, that the Elder Wand business worked out as it did.