I promise I'm still chipping away at Indestructible - I'm just in the middle of a frantic effort to complete my dissertation draft before the end of the semester. I should have another Indestructible piece up over the holidays though. Thanks for being patient!
Until then, I have a little question to toss out for consideration. It's been occupying my mind for a bit.
Question: Why did Voldemort believe that it was necessary to kill to gain the Wand's mastery?
Because he, of all people, should have known that it wasn't. If it were true, Albus Dumbledore would never have had it.
And he did believe, quite firmly, that Albus did.
*
Why did Voldemort believe that it was necessary to kill to gain the Wand's mastery?
He clearly did believe this, since he's willing to sacrifice Severus Snape's life to gain the Wand's mastery even though Severus has been (he thinks) the most useful of his servants and he shows a remarkable-for-him sliver of regret at having to lose the services of this "good and faithful servant."
This is the only time Voldemort shows regret for anything he does toward any of his followers. Severus is clearly exceptional among them in his mind by that point; he is the only one Voldemort ever treats with even minimal respect as well. He quite clearly weighed the loss of Severus' services carefully against the mastery over a period of time, before deciding that the latter was sufficiently important that having to kill his other tool was a worthwhile price to pay.
But why should he have believed that paying it was necessary in the first place? To the point of utterly neglecting to attempt to gain it via disarming first before moving on to the solution that deprives him of another useful tool? Instead, he seems convinced that, however much he would prefer to have Severus alive and useful, he can only gain the Wand by killing him. "It is the only way, Nagini."
Severus, he thought, had taken mastery of the Wand by killing Dumbledore, true.
But he knows firsthand of the existence of a living believed former master of the Wand. Gellert Grindelwald. The wizard Albus Dumbledore supposedly took mastery of the Wand from.
And then left alive, for Voldemort to go interrogate in person, and then kill himself, decades later. As we, and Harry, witness him doing. Here are the relevant bits of Harry's visions of the event (I've bolded what was italicized in the original):
Closing his puffy eyes, he allowed the pain in his scar to overcome him for a moment, wanting to know what Voldemort was doing, whether he knew yet that Harry was caught. . . .
The emaciated figure stirred beneath its thin blanket and rolled over toward him, eyes opening in a skull of a face. . . . The frail man sat up, great sunken eyes fixed upon him, upon Voldemort, and then he smiled. Most of his teeth were gone. . . .
“So, you have come. I thought you would . . .one day. But your journey was pointless. I never had it.”
“You lie!”
As Voldemort’s anger throbbed inside him, Harry’s scar threatened to burst with pain, and he wrenched his mind back to his own body [...]
As Harry spoke, his scar burned worse than ever, and for a few seconds he looked down, not upon the wandmaker, but on another man who was just as old, just as thin, but laughing scornfully.
“Kill me, then. Voldemort, I welcome death! But my death will not bring you what you seek. . . . There is so much you do not understand. . .”
He felt Voldemort’s fury, but as Hermione screamed again he shut it out, returning to the cellar and the horror of his own present. [...]
At once, Harry’s scar felt as though it had split open again. His true surroundings vanished: He was Voldemort, and the skeletal wizard before him was laughing toothlessly at him; he was enraged at the summons he felt - he had warned them, he had told them to summon him for nothing less than Potter. If they were mistaken . . .
“Kill me, then!” demanded the old man. “You will not win, you cannot win! That wand will never, ever be yours -“
And Voldemort’s fury broke: A burst of green light filled the prison room and the frail old body was lifted from its hard bed and then fell back, lifeless, and Voldemort returned to the window, his wrath barely controllable. . . . They would suffer his retribution if they had no good reason for calling him back. . . .
The fact that Gellert was still alive long after the duel in which Albus supposedly took mastery of the Wand from him leaves us with two basic options to consider:
1. Gellert spoke the truth. He never had mastery of the Wand - which, remember, he took by theft, not by any force, not even a disarming spell. Thus the entire line of supposed mastery from him onwards is empty.
2. Gellert lied, as Voldemort believed he was doing. He did have mastery of the Wand, and Albus took it from him when he defeated and disarmed Gellert.
If Gellert ever had mastery of the Wand, then killing its previous owner CANNOT be the only way that mastery is gained, since Gellert did not kill the previous owner. And if Albus ever had mastery, the same applies. He did not kill the previous owner either. This would fit with the actual course that we are supposed to believe the Wand's mastery followed: Gellert-->Albus-->Draco-->Harry. Assuming that, of course, anyone other than Death himself ever actually had mastery.
If killing the previous owner IS required, then neither Albus Dumbledore nor then Severus Snape could ever have had it. Nor Gellert himself.
Both of these things are quite basic and obvious inferences from the established fact that Gellert lived after the duel in which he supposedly lost mastery to Albus. A fact we KNOW Voldemort was entirely aware of.
(The possibility that killing is required, and Gellert had it - if Voldemort did not know how Gellert acquired it - but thus that Albus did not, would have been proven false to Voldemort when he himself killed Gellert and did not gain mastery.)
So how do we explain the curious fact that, after much searching and speculation and rumination upon the subject of the Wand's mastery, Voldemort quite clearly believed two obviously contradictory things: namely, that 1) killing a previous owner is "the only way" to gain mastery, and 2) that Albus Dumbledore took mastery of the Wand and left Gellert alive afterward?
Voldemort clearly believed that Gellert had mastery, and that mastery passed to Albus after their duel. This is the route that led him to believe Severus had it in the first place.
He also clearly believed that the owner's death specifically was what would pass the mastery on. He did not attempt to find out who disarmed Albus first, and did not speak to Severus of the latter's having 'defeated' or 'disarmed' Albus, or other such vague wording, but strictly of Severus' having killed him as the key fact. And he showed reluctance to kill Severus, overcome only by his having convinced himself after much thought that killing him was the sole way to gain mastery. Convinced himself so thoroughly of this, in fact, that he did not even pause to try disarming Severus before killing him, despite his reluctance at losing a useful servant.
(Had he showed no reluctance, had we not seen him talking himself into that conclusion and then demanding in a petulant rage that Severus confirm for him the necessity of his own death before Voldemort can bring himself to kill him, the entire problem would disappear. Severus' execution would simply be a slight, ah, overkill in the course of dealing with the matter in the simplest and most decisive manner. But that is decidedly not the situation as Voldemort sees it, given what we see.)
So how and why did he become convinced of this? He had recently been confronted directly with a living counter-example that utterly disproved either one or the other of the two central theses of his understanding of the mastery (depending on whether Gellert was lying or telling the truth). It doesn't matter which one was actually the one disproved; Voldemort's logic in thinking he must kill Severus Snape to gain the Wand depended utterly on both being true.
Impossibly.
And Voldemort, for all his flaws, is not actually stupid. Nor prone to under-thinking things. Quite the opposite. And he knows a great deal, supposedly, about the workings of dark magic.
So why, having clearly followed a trail that explicitly led him to believe that Albus gained mastery without killing Gellert, did he decide that the Wand's mastery from there could only be accomplished via killing?
What piece are we missing, here?
(Speaking Watsonianly, of course. Doylistically I think we can just attribute this to Rowling's lazy plotting and the utter lack of a competent editing job for DH. But I like at least attempting to explain what characters' reasons for things are...)