Harry Potter and the Deathly Hallows discussion thread (SPOILERS)

[Fabian]

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Ok, I finished reading it the second time. There are 7 horcruxs. Diary, Ring, Locket, Hufflepuff Cup, Ravenclaw Diadem, Harry, and Nagini. Well, Voldemort came back due to a horcrux or no? Was his father's bone a horcrux?

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Woah hold on I must have missed something. Wasn't it said all through books 6 and 7 that Voldemort split his soul in 7 because it was a magical number and all that? In that list, I count 8 parts (Voldemort himself being #8). Were Dumbledore just guessing about the 7 part soul thing, and did they not explicitly correct it at any point (which would explain why I missed it)?