Bube, I was pretty depressed after reading this. It just ends and nothing is explained, I want to read more!!
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I like the idea for RAB being Regulus, but I think Joe R. will mix it up a bit and not let it be so obvious, though it's not exactly obvious to the casual reader... hmm...
I heard a theory that Harry himself is the sixth "missing" Horcrux. It would explain why he feels what Voldermort feels and thinks and how, as Dumbledore said, Voldemort gave a little piece of himself to Harry when he cursed him. As I remember what we know so far, Voldemort was supposed to use Harry as a big kill (as in not just some Joe Wizard) to make his final horcrux, but for some reason it failed. So my guess is in his last moments after he failed in killing Harry, Voldemort instead made Harry his horcrux. I dunno, but it would make you think of the prophecy in a different way.
As for Snape, I like this mystery the most, and I have three reasons why I think he's good and not evil.
For one, I went back and reread the early on when he makes the Unbreakable Vow, and I remembered that Snape made the Vow to finish Malfoy's task if Malfoy were unable to do it. In other words, Snape didn't only have to protect Malfoy or face death by the vow (as I had remembered before rereading that chapter), he HAD to kill Dumbledore no matter what otherwise he would die. Dumbledore must have known this, because he knew about Malfoy's plan, and my guess is he made Snape take a promise to kill him if the time came (like he did with Harry). Perhaps that's the argument Hagrid overheard between DD and Snape.
Secondly, DD really has no use anymore. I'd rather him not be dead, but assuming that any normal wizard can't defeat Voldemort (even one as strong as Dumbledore), and only Harry can kill him, then if either him or Snape had to die in that confrontation DD might as well be the one to die in order to let Snape live. DD already told Harry everything he knew about the horcruxes and what must be done, while Snape can still serve a very powerful purpose by continuing to be a double agent in Lord Voldemort's cinner circle thing.
Thirdly, DD trusted Snape with no doubt in his mind, and I think it has to do with love. DD made such a big deal about the power of love with Harry and that love is the one power that Voldemort will never know, that I think DD knew Snape knew love. And I think Snape had loved Harry's mom. She was so good at Potions, a theory that I'm stealing is that, being the half-blood prince, he helped her with her potions homework. Then Harry's dad stole the help and used it against Snape, as was shown in the memory Harry saw with Harry's dad and Sirius. It would explain why he gets so mad when Harry tries to use Snape's magic from the potions book against him, and also help further explain why Snape hates Harry so much. It should have been his son....
Well, just ideas. I love the mystery...
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