How Harry Potter came back to life in Harry Potter and the Deathly Hallows is a simple question with a complicated answer. It’s one of those questions that come with a variety of theories. But at the end of the day, certain facts remain, and those are the facts we’ll examine here to figure out how exactly The Boy Who Lived survived not one Killing Curse, but two.
It began long before Harry even set foot in the Forbidden Forest with the Resurrection Stone in his hand, ready to die. In fact, it began before he even set foot on the Hogwarts grounds in Sorcerer’s Stone. Harry’s journey to the death actually began when he was just a baby and Professor Trelawney’s prophecy commenced Voldemort’s blood-thirty hunt to kill him.
As it is explained multiple times throughout the series, Lily Potter not only sacrificed herself for Harry, but created a magical protection in the process that would protect Harry from Voldemort until his dying day. But that wasn’t the only factor at play. In fact, there were so many factors at play when Harry sacrificed himself that it’s almost impossible to point at any one thing and say “that’s the reason why he survived.”
How did Harry Potter come back to life in Deathly Hallows?
As we know, in his quest for immortality, Voldemort created seven Horcruxes. But because Lily’s protection saved Harry from dying, when Voldemort tried to kill Harry his spell rebounded and actually killed himself — at least his corporeal body — and caused a bit of his soul to latch onto Harry’s.
When Harry decides to sacrifice himself in Deathly Hallows and walks willingly into the Forbidden Forest, he does so without raising his wand in defense. The next time he opens his eyes he’s in King’s Cross with Dumbledore in a kind of limbo. When he vocalizes his confusion to Dumbeldore — explaining that he meant to die — Dumbledore responds by saying. “And that will, I think, have made all the difference.”
Essentially Dumbledore is saying that because Harry didn’t defend himself, because he meant to die, he was able to come back. But again, that wasn’t the only factor at play.
Back in Harry Potter and the Goblet of Fire, Voldemort made the dumbest decision of his life by choosing to use Harry’s blood for the spell that would bring his corporeal body back to life. In doing so, he latched a part of Lily’s protective magic onto himself, which when you think about it made himself a version of a Horcrux for Harry. A Lovecrux, if you will.
What that meant for Voldemort is that he basically anchored Harry to Earth by having Lily’s protective magic inside him, and that as long as he was alive Harry couldn’t die. So, when Harry sacrificed himself, he woke up in limbo with the ability to choose to return to Earth because, one, he didn’t defend himself, and two, he still had Lily’s protective magic via Voldemort.
For being the most powerful dark wizard in wizarding history, Voldemort’s lust for power and immortality clouded his better judgment – if there was any to begin with. Maybe next time he’ll think twice about killing innocent babies. Oh wait, there won’t be a next time.