Muggles' Guide to Harry Potter/Magic/Horcruxes

Overview
For the definition of a Horcrux, see Horcrux.

The entire Harry Potter series revolves around the defeat of the Dark Lord, which cannot be complete until all the Horcruxes are destroyed. This article lists the Horcruxes and details about them as best they are known.

Extended Description
The entire Horcrux plot starts some forty years before Harry is born, when Tom Riddle asks Professor Slughorn about Horcruxes, whether if having one's soul in two places would allow return from death, would not multiple Horcruxes provide additional security? Would, perhaps, seven be a better number, as seven has so many mystical properties? Professor Slughorn is revolted at the idea, but Riddle does come away with the idea that it is not impossible. Professor Dumbledore, then Transfiguration professor, may have suspected that Riddle was studying Horcruxes; it is likely that he had already removed the books about Horcruxes from the library, as Riddle apparently claimed he could not find them. Hermione was able to retrieve these books from Dumbledore's study with the summoning charm.

Although there does not seem to be any mention of this fact in Harry Potter and the Half-Blood Prince, where Horcruxes were first introduced by name, it is mentioned in Harry Potter and the Deathly Hallows that Dumbledore thought Riddle had already made one Horcrux before his talk with Professor Slughorn. In fact, this is the case: according to the author, it was Tom Riddle Sr.'s death that allowed creation of the Ring Horcrux, and it was on the night that Riddle killed his father that he stole the ring from his uncle Morfin. In Slughorn's memory we see Tom wearing the ring. So the inescapable conclusion is that the ring was a Horcrux at that point, though almost certainly the only one.

Riddle generally chose to make Horcruxes out of items that had value to him, and chose to hide them in places that were significant to him as well. It is possible that as he created more Horcruxes, the soul shards that he was able to split off and set aside would each be weaker than the previous. Thus, one would expect that the first Horcrux he made would be stronger than the second, which would be stronger than the third, and so forth. This does not seem to be the case; while the remnant of soul that remained within Riddle apparently became very frayed and fragile, each of the Horcruxes was as strongly able to defend itself as the earlier ones.

In the end, Riddle (or Voldemort, as he is later known) does end up making seven Horcruxes, one of them accidentally. These are as follows:


 * 1) The diary Horcrux. Likely the first one created, and also the first one discovered, this was also made when Tom Riddle was still a student. The author has stated in an online chat that this Horcrux was made by means of Moaning Myrtle's death. Possibly an initial attempt, the value to Riddle of the diary was that it proved he was the true heir of Slytherin; interestingly, it only gained this value after it was made into a Horcrux. This is the only Horcrux that actually generates a simulacrum of Riddle, perhaps it is the only one that is actually allowed to. Hermione's reading suggests that a Horcrux can use the life-force of someone who gets emotionally close to it, using that to regenerate the person who provided the soul, and this is evidently what happened in this case: Riddle regenerated using Ginny's life force. We can see that the diary took no damage from being flushed down the toilet or having ink spilled all over it, which is what we would expect given the characteristics of a Horcrux. This Horcrux was destroyed by Harry in Harry Potter and the Chamber of Secrets using a Basilisk fang. Dumbledore was actually disturbed by the discovery of this Horcrux; while he had suspected that Riddle had made a Horcrux, the almost cavalier way that this one was risked, solely in order to make trouble, seemed to suggest that it had a rather lower value than a Horcrux, being a ticket to immortality, ought to have.
 * 2) The ring Horcrux. Very likely the second Horcrux Riddle made, and the second one discovered, this was probably made shortly before we see it on Tom's finger in his fifth or sixth year. The author has stated that it was the death of Tom Riddle Sr. that allowed the creation of this Horcrux. While Dumbledore does not believe Riddle would have wanted to continue wearing it once it was made into a Horcrux, it is possible that Riddle did not yet have any safe place to keep it at that point. He eventually hid it, magically protected, in the ruins of the Gaunt shack; it is certain that he would not actually want to hide it there until he was certain that the original occupants would not be returning. It is also certain that he did not know exactly what the ring was; Marvolo Gaunt thought it was a signet ring bearing the coat of arms of the Peverell family, but the device etched onto the surface was, in fact, the sigil of the Deathly Hallows. The significance of the ring to Riddle was, of course, the illustration of the connection to the pure-blood Peverell family, just as it had been to Morfin Gaunt and Marvolo before him; and its hiding place was significant because it was the home of his mother and grandfather, and thus served as partial proof of his heritage. Professor Dumbledore had retrieved it from there; then, knowing Dumbledore was preparing to destroy it, the Horcrux apparently managed to convince him to put the ring on his finger. The resulting action of the embedded curse caused the damage to Dumbledore's hand that was apparent in Harry Potter and the Half-Blood Prince, and in fact left him with, at best, a year of life. Dumbledore managed, despite the curse, to return to his office, where he destroyed the Horcrux using the sword of Godric Gryffindor.
 * 3) The locket Horcrux. This is the third Horcrux discovered, but likely the fifth made. The author has stated that it was created from the death of a Muggle tramp. The locket is significant to Tom Riddle (now calling himself Lord Voldemort) because of its direct connection to Salazar Slytherin, who espoused the same belief in pure-blood superiority that Voldemort has adopted, and because it serves as proof that he is descended from Slytherin. The first time we see it, before it is a Horcrux, it is around the neck of Merope Gaunt. She evidently then sells it for a pittance, and it goes on to become one of Hepzibah Smith's treasures. Shortly after Hepzibah's death, it vanished; apparently Tom Riddle had, at this point, stolen it and made it into a Horcrux. As a Horcrux, it was originally hidden in the basin in the cave, which was visited by Harry and Professor Dumbledore in Harry Potter and the Half-Blood Prince. This cave was significant to Voldemort because it was one of the places where he had first exercised his superiority over Muggles, by torturing some of his fellows from the orphanage. The locket was then stolen by Regulus Black, who replaced the locket with the one that Harry and Dumbledore found, and who passed the locket on to Kreacher with instructions to destroy it. Kreacher was unable to do so. It then passed through Mundungus Fletcher's hands to Dolores Umbridge. Harry and Hermione managed to steal it from Dolores, and eventually Ron destroyed this Horcrux with the sword of Gryffindor. The locket had to be opened before it could be destroyed; Harry discovered that it would open if spoken to in Parseltongue.
 * 4) The cup Horcrux. This is the fourth Horcrux retrieved, probably the fourth one made, and according to the author was made via the death of Hepzibah Smith. The cup is significant to Voldemort because of its direct connection to Helga Hufflepuff, one of the Four Founders of Hogwarts. We first see it in Hokey's memory, when Hepzibah Smith is showing off her treasures, and assume that it is stolen by Voldemort at her death, at the same time he recovers Slytherin's locket. When we next see the cup, it is locked away in a top-security vault at Gringotts. Harry believes that the location is significant to Voldemort because possession of a vault at Gringotts is proof of ancient Wizarding heritage. The vault is owned by Bellatrix Lestrange, and Voldemort is furious when the Horcrux is stolen from there. The report of the theft of the cup Horcrux starts Voldemort inspecting the places where he has hidden all his Horcruxes to confirm that they still are safe. To his fury, he finds that they are not. The cup Horcrux is carried out of Gringotts by Hermione, and destroyed by her at Hogwarts using a Basilisk fang recovered from the Chamber of Secrets.
 * 5) The diadem Horcrux. This is the fifth Horcrux retrieved, but possibly the third one made. It was while he was at Hogwarts that Riddle had charmed (non-magically) the Grey Lady into telling him where the lost Diadem of Ravenclaw was. The Grey Lady, in life Rowena Ravenclaw's daughter, had stolen the diadem and had hidden it in Albania, in a hollow tree. She had then been murdered by the man who became the Bloody Baron, before she could either retrieve it or tell anyone where it was. Riddle managed to get its location, and having retrieved it, converted it into a Horcrux, apparently by murdering an Albanian peasant, according to the author. The value of the Diadem to Voldemort was obviously its connection to Ravenclaw, one of the four Founders. Visiting Hogwarts ten years after the death of Hepzibah Smith, Voldemort had hidden the diadem in the Room of Requirement in its "junk warehouse" state. The significance of this location to Voldemort is two-fold: like Harry, Riddle found Hogwarts to be the first place that he could truly call his home, and unlike Harry, he believed that he was the only person who knew how to get into the Room of Requirement. Harry had seen, and handled, the diadem when he went into the Room of Requirement to hide his Potions textbook in his sixth year, but had not recognized it; of course, he had not even known it existed at that point. It is because he had used it as a marker for the place he had hidden his textbook that he was able to remember it. This Horcrux was destroyed by Vincent Crabbe, who had learned how to create Fiendfyre but not how to extinguish it. The fire he created would have destroyed everything in the Room of Requirement at that point, and in fact consumed him as well. We see that the Fiendfyre is tossing the Diadem through the air when Harry catches it, and it falls apart in Harry's hands, without any assistance from Harry, after he leaves the Room of Requirement; we can only assume that the Horcrux was "fatally" damaged by the actions of the Fiendfyre.
 * 6) Nagini. The seventh Horcrux created, and the fifth revealed, Nagini was used as something of an afterthought. Voldemort needed a sixth Horcrux to complete what he thought was the mystical number of soul pieces (seven), and Nagini was handy at the time when he was murdering Bertha Jorkins. (Voldemort was unaware of the existence of the accidental Horcrux at that point, and remained so throughout the series.) Nagini had been his constant companion to that point, and after becoming a Horcrux, started showing certain human characteristics. It is certain that Nagini and Voldemort were sharing their thoughts when Harry viewed Nagini's attack on Arthur Weasley. Once Voldemort knew that his Horcruxes were under attack, he created protective spells around Nagini to keep her safe; but once Harry was believed dead, he no longer thought that necessary. Nagini was beheaded by Neville Longbottom, using the sword of Gryffindor which had been provided to him by the Sorting Hat.
 * 7) Harry. The sixth created, and the seventh one revealed, Harry, who doesn't actually merit use of the term "Horcrux", was purely accidental. It was revealed in Harry Potter and the Deathly Hallows that the act of murdering Harry's parents had caused Voldemort's already shredded soul to tear again, and the detached fragment sought and attached itself to the nearest intact soul it could find, which was Harry's. This soul fragment, resident in Harry, gave him some of Voldemort's abilities, notably the ability to speak to snakes, and provided him an awareness of Voldemort's thoughts and feelings throughout the seven books. Voldemort destroyed this soul fragment when he tried to kill Harry the second time, in Harry Potter and the Deathly Hallows; he was unable to kill Harry at that time because of the blood protection Harry still carried. But the author has said that with the destruction of the soul fragment, Harry lost the ability to speak Parseltongue.

Analysis
It is perhaps interesting that no person destroyed more than one Horcrux. Harry, Ron, Hermione, Neville, Dumbledore, Crabbe (indirectly: the diadem fell apart in Harry's hands after being damaged by Crabbe's fiendfyre), and Voldemort each destroyed one of the seven. This illustrates a point that Harry has been trying to make throughout the series, but only verbalizes while in the process of setting up Dumbledore's Army in Harry Potter and the Order of the Phoenix: Harry didn't do all this stuff alone, he had loads of help.

One thing that must be noted is that re-embodiment does not "use up" a Horcrux. Despite being sheared apart, all of the "soul fragments" remain connected, and the purpose of a Horcrux is to anchor the principal soul remnant to the earth by securing the sheared-off portion in an artifact that cannot be translated. When you die, your soul is freed to make the next step; if you have made a Horcrux, that fragment of soul is tied to the ring you used (e.g.) and holds the rest of your soul to the Earth. The Horcrux we see in Harry Potter and the Chamber of Secrets is an anomaly in this case. It was acting independently, as the principal soul shard had been earlier, to take over another person. In Harry Potter and the Philosopher's Stone, the principal soul fragment partly took over Professor Quirrell, but on Quirrell's death it was released to return to Albania. In Harry Potter and the Chamber of Secrets, if the soul fragment had succeeded in rebuilding itself from Ginny's life force, killing the reconstituted Tom Riddle would almost certainly have freed the soul fragment. Harry destroyed the diary before the Horcrux was fully extracted from it, which similarly freed the soul fragment.

We noted earlier that Voldemort's plan was for there to be seven soul fragments, the original plus six Horcruxes; and Harry's gaining a soul fragment from Voldemort was not actually a Horcrux, as the charm that binds the sheared-off soul fragment to an object was not completed, if it was even begun.

While a murder is necessary to create a Horcrux, it is not sufficient. While the act of murdering someone does result in the soul being torn apart, according to Professor Slughorn, Professor Dumbledore implies that the separated soul fragment will attempt to return to the soul that it was sheared from and re-integrate. This is why Harry carried a piece of Voldemort's soul: it was torn free, but when it attempted to re-attach, Voldemort's soul was no longer there, having been blasted away by the backfire from the Avada Kedavra spell. Creating a Horcrux requires a spell to keep the sheared-off fragment from re-attaching, and to embed it in some object, so while the soul fragment within Harry probably would have acted to hold Voldemort's soul in this plane, it is not actually bound to Harry. Dumbledore commented at one point that he believed Tom's soul was so frayed and damaged by the repeated murders that he could no longer sense when a Horcrux was destroyed; it is uncertain, but is it not possible that one who committed enough murders would be left effectively soulless when their soul frayed away to nothing?

Greater Picture
One question that has been debated is whether the Elder Wand, an exceptional wand, would provide sufficiently strong magic to destroy a Horcrux? We learn that a Horcrux can defend itself against any damage that could be inflicted by ordinary magic; the Elder Wand, of course, is an extraordinary magical artifact, is not its magic strong enough to destroy a Horcrux? After all, the Killing Curse, cast by Voldemort at Harry using that wand, was sufficient to dispatch the soul fragment that Harry had been carrying; and the wand had not accepted Voldemort as its master at that point.

There is nothing in the books that directly addresses this question. However, it is possible to speculate, and based on that speculation, the apparent answer is that no, the magic of the Elder Wand is not sufficient in and of itself. Our reasoning is as follows: Why did Dumbledore travel all the way back to Hogwarts from the Gaunt shack, and fetch the Sword of Gryffindor out of a display case to break the ring Horcrux if the Elder Wand, of which he was the full master, could have done the job? The apparent difference is this: a Horcrux is a soul fragment that is bound to an object. What was in Harry was in fact not a proper Horcrux at all, but simply a piece of soul more or less along for the ride; as partial evidence for this, we mention that at no time did Dumbledore refer to it as a Horcrux, but always rather as a "soul shard" or "piece of Voldemort's soul." Others, notably Severus Snape, referred to it as a Horcrux in conversation with Dumbledore, and Dumbledore did not contradict them, but also did not agree or use the term himself. Dumbledore also notes that "it is inadvisable" to use a living thing as a Horcrux "because to confide a part of your soul to something that can think and move for itself is obviously a very risky business." (Harry Potter and the Half-Blood Prince chapter 23, Raincoast edition p.473) This leaves it open as to whether the soul fragment is at risk of destruction if the living creature housing it is killed, or if it remains bound to the body after death of the original resident, so to speak, or if the concern is that the being housing the Horcrux might stray into extraordinary danger on its own part. The sole example we see of this is Nagini, and as she is killed with a weapon that has destroyed Horcruxes, the destruction of the Horcrux in that container is inconclusive.

In order to speculate on what happened there, we also have to speculate on the nature of the Avada Kedavra curse. To wit: Harry's experience in Harry Potter and the Deathly Hallows leads us to believe that one of the effects of the Curse is to separate soul from body. But that cannot be the full effect; the Curse also works on spiders, and nobody teaches us that spiders have souls, and the end effect of the Dementor's Kiss is not a dead body, but one that is merely "as good as dead". So we have to assume that the Curse also damps the life force somehow... but we can assume that it did not do so in the Forbidden Forest, primarily because Voldemort still had one extant Horcrux, Nagini, even after the soul shard in Harry was dispatched. (Otherwise, Voldemort would have died in the Forest from that spell rebound.) So, the Curse separated Harry's soul, with its rider, from his body. The soul fragment, separated from Harry by the shock, may have tried to return to Voldemort's soul and reattach, and been rebuffed; and then would have evaporated, as the other Horcrux soul fragments apparently did. While it is possible that this particular fragment did reattach, Harry later says that Voldemort must "have some remorse" for his actions, echoing Dumbledore who says that is a necessary part of re-integrating the separated soul fragments. As Voldemort has never felt remorse, we believe that the soul fragment within Harry was not able to reintegrate with what was left of Voldemort's soul.

We can also speculate that the soul fragment riding Harry, lacking the blood protection that Harry carried within him, would have been susceptible to destruction or expulsion by Voldemort's curse, at least more so than Harry would have been. While one could potentially argue that Voldemort's soul shard could be protected from Voldemort because of shared blood, that is not the case; Voldemort's blood came from Harry, and the soul shard from an earlier instance of Voldemort who was using his own flesh and blood.

It is almost certain that the magic that was used to make a Horcrux out of Nagini was the same as the magic that was used to make the other Horcruxes, in which case the soul fragment could be bound, not to Nagini's reptilian soul but to her body, and as such it could have remained intact despite Nagini's death, bound to her remains. It is certainly possible that a Horcrux bound to a living being is freed with the being's death, though that would be a rather brief form of immortality, in which case Nagini's death by use of any weapon would have released that Horcrux. Of course, the fact that she was killed with the Sword of Gryffindor, and its Basilisk-venom infusion, will have put an end to the Horcrux.

To conclude, then: A soul fragment bound to an object, a Horcrux, is proof against ordinary magic, even magic as strong as that produced by an extraordinary wand. (At least, evidence is that Dumbledore believed so, and we have seen nothing against that.) The soul fragment within Harry is not actually bound to him, but is merely clinging to his own soul, and as such is only as strong as Harry himself; if Harry's soul is separated from his body, the soul fragment is detached and vanishes. And the soul fragment within Nagini, we believe, is bound to its container (Nagini's physical body) by the Horcrux magic, and likely would act to keep that container intact, even after Nagini's original "soul" or life force had vanished; it is only the sword of Gryffindor, with its dose of Basilisk venom, that is able to dispatch it.