Enter the obvious questions: “But doesn’t Dumbledore say Harry survived because of the protection created by his Mother’s sacrifice 16 years earlier? Didn’t her love create a shield over Harry that funnelled the curse into the Horcrux?”
To paraphrase WippitGuud, you can bet four galleons, a round of butterbeer and all the Chudley Cannons' Firebolts that that didn’t happen. Harry died. Sorry.
What's the evidence?
It's fourfold:
i) When baby Harry was hit by the killing curse, it rebounded and hit Voldemort. That doesn’t happen second time round.
ii) Remember Harry’s lightning bolt scar? Voldemort didn’t leave a mark on Harry in the forbidden forest. Well, at least not anywhere visible, but let's keep this theory PG.
iii) To destroy a Horcrux, the container must be destroyed – think the locket, diadem, the diary and, well, every Horcrux. Simply put: if part of Voldemort’s soul in Harry needed to be killed then Harry needed to pop his clogs too.
iv) After the events in the forest, Harry’s allies in Hogwarts were given the same protection by Harry that Lily gave to her son – protection that could only be forged if Harry died. As Harry says to Voldy: "I've done what my mother did. Haven't you noticed how none of the spells you put on them are binding? You can't torture them. You can't touch them."
Don’t even pretend like you’re not convinced: Harry Potter actually died.
So, how does Harry bring himself back to life?
Simple: since Harry was master of all the hallows (including the Elder Wand), thus master of death, he could resurrect himself. Anything else?
Yes, actually: why did Dumbledore lie to Harry?
Why would Dumbledore be telling porkies in Kings Cross? Why did his former headmaster play the ‘Lily love’ card again instead of revealing Harry’s full house of Hallows? Because, as WippitGuud explains, Dumbledore was protecting Harry: “knowing you're the master of the Hallows could make anyone power hungry.” Just remember, Dumbledore was happy to lie to Harry for years about his relationship with Voldemort. Case closed.
So, this theory in short: Harry needed to die to defeat Voldemort, but Dumbledore tried to keep Harry in the shade again.
Truth level: veritaserum.
