Brilliant! To have noticed the two spells that came from who-knows-where and to have them such unexpectant sources! That Lucius didn't want Voldemort's return is hinted at in the graveyard scene, where he accuses Lucius of not looking for him. (I agree that Lucius also wanted the book/monster destroyed after Dumbledore was ruined and the insulting search on the Manor was avenged.) That Lupin was the one to have killed Sirius - and why - is a totally new twist on the whole Marauders saga! Thank you for this top-quality matched set!
Author's Response: I didn't make up the "Lupin killed Sirius" concept. As far as I know, "Pippin" is the originator, and she put together a traitor-Lupin theory as long ago as Dec 2004. I'm not convinced that Lupin is a long-time traitor, but I do believe that his moral weakness, which betrayed Harry (and everyone) in PoA, could lead him to betray again in DH. He would withstand torture and death threats, I think, but not blackmail. As for Lucius, I've been considering the idea that he *threw the fight* for a while, but it was only today that I decided when. I had wondered if he intended all along to throw it - because otherwise why not simply Accio the prophecy as soon as Harry took it from the shelf, before Harry even realised they were there - but that didn't fit with telling the Death Eaters that they could kill the other kids, so I looked for a point later in the scene and this one just jumped out at me. JK's very good at ambiguity, isn't she?