Comment by edkeyes on Harry Potter and the Methods of Rationality discussion thread, March 2015, chapter 121 · 2015-03-14T03:50:30.601Z · LW · GW

Someone else may have already come up with this interpretation, but I just wanted to get a prediction posted before the last chapter comes out.

Voldemort most likely had turned the diary of Roger Bacon into one of his horcruxes. The book was described as unusually durable, and it was given to Harry at a point in the story before Voldemort acquired the Resurrection Stone, so horcruxes would have worked only by touch. Needless to say, it was to his advantage to have one in Harry's possession, to be able to potentially take over the body of Tom Riddle v2.0 if the whole Quirrell thing didn't work out.

And now the diary is (supposedly) Hermione's horcrux too. Oh, dear. Since Voldemort wrote her into Harry's Vow as a required source of advice and restraint, he would have wanted to retain the option to influence that advice and force Harry away from dangerous decisions. So mixing horcruxes together in the same object might have been intended to give him the option to take over Hermione's body with access to her memories, if his plans failed to the extent of Harry surviving the night of the final exam.

With his personality now Obliviated, the mixing of souls might work in the other direction. My prediction for the final chapter is that Hermione has retained her personality but now has access, at some level, to Voldemort's accumulated magical lore, and possibly to things like passwords to his hidden caches of artifacts (since they'll eventually need to get the Resurrection Stone back to finally get the Hallows together).

This would be a neat last twist, opening a lot of possibilities for Harry and Hermione to kick off a collaboration on solving the problems of the universe in subsequent years. And the parallelism is elegant: the Girl-Who-Revived acquires a fragment of the vanquished Voldemort just as the Boy-Who-Lived originally did. We'll see if she gets a dark side too. ;-)

Comment by edkeyes on Harry Potter and the Methods of Rationality discussion thread, part 21, chapters 91 & 92 · 2013-07-04T18:38:33.778Z · LW · GW

The likelihood of this theory is definitely boosted by "Hermione's" last words, as that's exactly the message that a disguised McG would want to give him.