SPOILERS, SPOILERS, SPOILERRRRSSSS!!
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6. Harmony/Harmione was a possible pairing, but then Rowling changed her mind.
7. The Hufflepuffs were the only House that were right about Sirius Black: "Maybe he disguised himself." (Can't be sure that was the actual quote... Too lazy to check)
8. Sirius didn't die because of Bellatrix's Killing Curse. He died because he fell through the veil.
9. Tom Riddle/Voldemort is incapable love because he was conceived under the effects of a love potion.
10. The Crumple-Horned Snorkack does not exist; Xenophillius made it up and Luna believed him. Nargles and other creatures mentioned by Luna, however, are likely to exist.
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Thank you @author422 for correcting me on No. 10!!
