Can one person have multiple souls?

Question

When Voldemort tried to kill Harry in the first book, a fragment of his soul split off and continued to live in Harry. Harry had his own whole soul and the part of Voldemort's soul in him from then on.

Due to him having more than one soul in him, he could not be killed by Voldemort in the Forbidden Forest in the seventh book. Voldemort's Killing Curse merely destroyed the fragment of his soul inside Harry, but Harry's own soul stayed intact.

Harry basically had two lives and Voldemort's Killing Curse destroyed one of them. Couldn't any dark wizard force others to put a bit of their soul into his body to have multiple lives?

For example, dark wizard A forces servant B to perform the Horcrux making procedure. B doesn't put the split off soul fragment into an object though but instead into A. A now has his soul and additionally a part of B's soul -> Two lives. If A was hit with the Killing Curse, just one soul would be destroyed and A could live on with one life less.

Does this make sense or have I missed something?

Answer 1

Yes, a living being can be turned into a Horcrux.

It’s definitely possible to use a living being as a Horcrux. The Dark Lord does so with Nagini, and Harry unintentionally having a piece of the Dark Lord’s soul shows that humans presumably can be turned into intentional Horcruxes (though they’ll have even more independence than animals).

“The snake?’ said Harry, startled. ‘You can use animals as Horcruxes?’

‘Well, it is inadvisable to do so,’ said Dumbledore, ‘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 (Horcruxes)}}

So, it is indeed possible for someone to have multiple souls - their own whole soul and a piece of someone else’s as a Horcrux.

But having a bit of someone else’s soul likely can’t protect you.

However, getting someone to use you as a Horcrux probably won’t keep you alive if you’re hit by a Killing Curse - Harry was tethered to life by his blood and therefore Lily’s sacrifice in the Dark Lord, not having a piece of the Dark Lord’s soul for the Killing Curse to hit instead.

“He took your blood believing it would strengthen him. He took into his body a tiny part of the enchantment your mother laid upon you when she died for you. His body keeps her sacrifice alive, and while that enchantment survives, so do you and so does Voldemort’s one last hope for himself.”
_{^{- Harry Potter and the Deathly Hallows, Chapter 35 (King’s Cross)}}

If his blood wasn’t externally tethering him to life in the Dark Lord, then the Killing Curse would have simply killed both the piece of the Dark Lord’s soul and Harry himself. That Harry ended up ‘dead’ enough to go to Kings Cross shows the curse could have killed him as well.

Answer 2

Your question is based on a wrong assumption: that the Killing Curse (or any other form of dying) kills only one soul at once, so that if you have multiple souls, something is left over.

This assumption is wrong. Under normal circumstances the Killing Curse would have simply killed both souls in Harry's body and he would simply be dead.

The reason the Killing Curse did not affect Harry's own soul but killed off the fragment of Voldemort's soul was due to the protection that Harry still had through the sacrifice of his mother and Voldemort having extended that protection by taking some of his blood when gaining his new body.

So, without the very special circumstance of having a part of somebody else's soul in your body, you are not protected from anything.

Answer 3

As others have already pointed out, it's not having an additional soul as a "second life" that lets Harry survive, it's the fact that Voldemort has used Harry's blood for his resurrection. When Harry tells Dumbledore the Voldemort used his blood, there is this observation:

For a fleeting instant, Harry thought he saw a gleam of something like triumph in Dumbledore's eyes. (GoF)

Dumbledore later explains that it is the blood that let Harry survive.

His (Voldemort's) body keeps her (Lily's) sacrifice alive, and while that enchantment survives, so do you (Harry). (DH)

---

But the main misunderstanding in the question "Can one person have multiple souls?" is that you associate a person with the body and not with the soul. Both in religious contexts and in Harry Potter, the soul is the essence of a person, not the body. The soul is permanent, the body is not.

Voldemort's body is destroyed then he tries to kill Harry, yet he survives. When he is resurrected, his Body is different and more snakelike than he was before.

‘Robe me,’ ... The thin man stepped out of the cauldron, staring at Harry ... and Harry stared back into the face that had haunted his nightmares for three years. Whiter than a skull, with wide, livid scarlet eyes, and a nose that was as flat as a snake’s, with slits for nostrils ... (GoF)

When people die, an echo of their soul can remain, either as ghosts, or something stronger in the case of the Priori Incantatem.

even though the thick grey ghost of Cedric Diggory (was it a ghost? It looked so solid) emerged in its entirety from the end of Voldemort’s wand (GoF)

"No spell can reawaken the dead," said Dumbledore heavily, "All that would have happened is a kind of reverse echo. A shadow of the living Cedric would have emerged from the wand."

So the question would be "Can one body have multiple souls at the same time?" While it can happen with possession and Horcruxes, it doesn't provide the protection you asked about.

Answer 4

Throughout all the described events, Voldemort clearly does not understand exactly what is happening. He does not expect to lose part of his soul to Harry, nor does the dark lord expect that seventh part of his own soul to protect Harry from a killing curse. None of how this soul transfer worked was understood by Voldemort, or probably by anybody; so there was no way the process could be manipulated.

In the future, witches and wizards will be aware of this soul transfer phenomenon. Perhaps an extremely powerful dark wizard could use this technique intentionally to protect themself. However, whether or not it would work would still depend a great deal on variables that are not understood. Can someone transfer part of their soul (for the benefit of the recipient, not merely to hide the soul) intentionally? Does the protection work against a killing curse from anyone, or just the soul donor? The answers to these crucial questions are not known.