From: DeathChicken | #036
He knew earlier, when he looked at Snape's memories in the Pensieve. That's why he went after Voldemort, since he thought he had to let him kill him to get rid of it
Oh, that's right. Man, it's extremely fortunate that Harry managed to stumble across Snape just before his death, then. If he hadn't done that, he never would've learned he was the seventh horcrux.He'd defeat Voldemort because of dumb elder wand mechanics, but Voldemort would just come back again and Harry would have no idea why. As he breaks the elder wand shortly after, he'd no longer have dumb elder wand mechanics to hide behind, and Voldy may even realize what his seventh horcrux is and not kill Harry. Just imprison him for the rest of his life while Voldemort goes on to take over the world.
Yet another aspect of the series' finale that hinges on pure luck, hooray!
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