The following is a quick guide to Horcruxes: what they are, how to create them, how to eliminate them, and their powers.

“Of the Horcrux, wickedest of magical inventions, we shall not speak nor give direction–”

—introduction of Magick Moste Evile

Quickly put: Horcruxes are an object with a piece of somebody’s soul inside.

A soul in the Harry Potter universe is represented as a whole. Albus Dumbledore explains to Harry Potter that a whole is more powerful than a fragment. But clearly if one can split it in this fantasy series then a soul must be made out of parts. J.K. Rowling once said that creating a Horcrux is equivalent to splitting an atom. The spitting of one’s soul, like splitting an atom, is hardly wise because the remaining structure is unstable.

“Something that people imagined might be able to be done, but couldn’t quite bring it off, and then… and then people started doing it with sometimes catastrophic effects.”

It was believed that a Horcrux would keep a wizard alive because with his soul in pieces it could not move on to the afterlife. This greatly appealed to Voldemort who was researching ways into achieving immortality. He did many other things besides creating Horcruxes (though we don’t know what) because he wasn’t certain which process would actually work.

Lord Voldemort was the only wizard smart enough or foolish enough to attempt more than one split. He aimed for the magical number 7, believing that 7 pieces of soul were more powerful than 1 whole soul. He failed to create 7 and actually created 8 slices, which we can only suppose aided in his downfall. According to Horace Slughorn no wizard would possibly want to be in such a state and would prefer death instead as the creation of one makes the creator less human. This perhaps explains Voldemort’s mutated appearance into a snake-like creature.

Voldemort’s 8 soul fragments: Riddle Diary, Slytherin Locket, Hufflepuff Cup, Gaunt Ring, Harry’s Scar, Nagini, Ravenclaw Diadem, Voldemort himself

Once the fragment of soul is carefully split away it is forced into an object. It could be any object, but in Voldemort’s case he selects very specific trophy-like items in which to store his soul. Once Harry and Dumbledore saw the pattern it was only too easy to figure out what the objects were.

Hermione: “This is the one that gives explicit instructions on how to make a Horcrux. Secrets of the Darkest Art – it’s a horrible book, really awful, full of evil magic… And the more I’ve read about them, the more horrible they seem, and the less I can believe that he actually made six. It warns in this book how unstable you make the rest of your soul by ripping it, and that’s just by making one Horcrux!”

The process of creating a horcrux is fairly vague in the book series, but Rowling plans to explain further in a future release about the Harry Potter series. The rumor is the editor wanted to vomit after reading about it. What we know is this – it involves a murder and a spell – and it is considered a violation of moral decency and natural laws.

Once the Horcrux is created it is possible to un-create it by the original creator. It would invariably cause the creator great pain. Rejoining the soul could even possibly kill the witch or wizard in the process.

Ron: “Isn’t there any way of putting yourself back together?”

Hermione: “Yes, but it would be excruciatingly painful… Remorse. You’ve got to really feel what you’ve done. There’s a footnote. Apparently the pain of it can destroy you. I can’t see Voldemort attempting it somehow, can you?”

Clearly this will never be done by Voldemort, because he does not feel remorse. He will never feel remorse because he’ll never want to put his soul together. Voldemort created his Horcruxes because he wanted eternal life.

Lucky for Harry and the wizarding world, Horcruxes can be destroyed by anyone. It did not have to be reabsorbed by the creator to be destroyed. This is why Voldemort took such great care and went to such great lengths to hide his Horcruxes and to lay traps for them.

Destruction of a Horcrux requires that the object housing the soul fragment to be damaged beyond all magical aid. When a Horcrux is so damaged it can appear to bleed out and a scream may be heard as the soul fragment perishes. This is not always the case and nobody knows why a Horcrux will or won’t act that way.

Known ways to destroy a Horcrux include Basilisk venom (most deadly poison), fiendfyre (so hot everything must melt), killing curse (on living hosts), Godric Gryffindor’s sword (because it was Goblin made and absorbs only that which makes it stronger, like Basilisk venom).

Ron: “The bit of soul in that diary was possessing Ginny, wasn’t it? How does that work, then?”

Hermione: “While the magical container is still intact, the bit of soul inside it can flit in and out of someone if they get too close to the object. I don’t mean holding it for too long…I mean close emotionally. Ginny poured her heart out into that diary, she made herself incredibly vulnerable. You’re in trouble if you get too fond of or dependent on the Horcrux.”

Horcruxes think for themselves and will act to protect themselves from external threats. They can possess witches and wizards who don’t know what they are dealing with. Arthur Weasley gives very good advice:

“Never trust anything that can think for itself, if you can’t see where it keeps its brain.”

This is what happen to Ginny in Chamber of Secrets. She trusted the diary to be her friend and opened herself up to it emotionally. If Harry hadn’t rescued her and destroyed the Riddle Diary Horcrux, Ginny’s life force would have been swallowed up by the Horcrux and used to give the soul fragment a new body. Not good! The Slytherin Locket Horcrux made the golden trio moodier and paranoid. Long term exposure was breaking down their will power and who knows perhaps eventually it too would have tried to used one of them to gain a new body.