why do you think voldemort didn't just kill snape with the old new avada kedavra, and why kill snape at all? he knew the elder wand didn't require the death of its previous master
I think thatās a really good question, because Iāve seen people theorize that Voldemort hesitated to kill Snape with a wand and used Nagini instead because he never actually intended, or wanted, to kill him. And while I do think it makes sense that he hadnāt initially planned to, the idea that he didnāt really want to can be answered differently. Voldemort was both frustrated and apprehensive that the Elder Wand did not recognize him as its true master. In fact, Voldemort had already convinced himself that the Elder Wandās allegiance could only be secured through its masterās death. And for someone who consistently treats another personās death as a sacrificial means to an end, Snape became the inevitable cost.
āWhy doesnāt it work for me, Severus?ā
In the silence Harry imagined he could hear the snake hissing slightly as it coiled and uncoiled ā or was it Voldemortās sibilant sigh lingering on the air?
āMy ā my Lord?ā said Snape blankly. āI do not understand. You ā you have performed extraordinary magic with that wand.ā
āNo,ā said Voldemort. āI have performed my usual magic. I am extraordinary, but this wandĀ .Ā .Ā . no. It has not revealed the wonders it has promised. I feel no difference between this wand and the one I procured from Ollivander all those years ago.ā
Voldemortās tone was musing, calm, but Harryās scar had begun to throb and pulse: Pain was building in his forehead, and he could feel that controlled sense of fury building inside Voldemort.
Being caught between a furious Dark Lord and the very object he believed would most legitimize his claim to power ā a tool that was refusing to answer to him ā left Snape, one of his finest Death Eaters, as the sacrifice Voldemort believed had to be made in order for the Elder Wand to finally acknowledge him. In Voldemortās eyes, anyone in Snapeās position would have met the same fate simply by standing, however indirectly, in the way of Voldemortās legitimacy as the wandās ātrue masterā.
āThe Elder Wand cannot serve me properly, Severus, because I am not its true master. The Elder Wand belongs to the wizard who killed its last owner. You killed Albus Dumbledore. While you live, Severus, the Elder Wand cannot truly be mine.ā
Besides Voldemort already being bothered and uneasy that the wand wasnāt working, it also perfectly explains why he wouldnāt have wanted to risk his own Killing Curse rebounding and killing him instead (he has experienced this before). So why take that risk by casting the spell directly at the wizard he believed to be the Elder Wandās master, when he could already feel the wand resisting him? Using Nagini was the next most straightforward solution.
Moreover, unlike the final duel between Harry and Voldemort ā where Nagini was no longer an option, forcing Voldemort to rely on Avada Kedavra (his most powerful spell) in a far more critical and emotionally charged moment (when he was visibly desperate) ā here, as Voldemort himself says, he could stil find himself āwondering, wondering, why the Elder Wand refuses to be what it ought to be.ā
There was a terrible scream. Harry saw Snapeās face losing the little color it had left; it whitened as his black eyes widened, as the snakeās fangs pierced his neck, as he failed to push the enchanted cage off himself, as his knees gave way and he fell to the floor.
āI regret it,ā said Voldemort coldly.
He turned away; there was no sadness in him, no remorse.
Also, I think itās significant that the narrative deliberately uses two closely related words when describing Voldemortās emotions. Iāve seen people conflate the two, since both are associated with sorrow depending on the context. But here, Voldemortās regret comes from disappointment; from believing the situation could have unfolded differently and spared him the necessity of Snapeās death, a death he relied upon because of the decision he believed he had to make.
In other words, he regretted the outcome, but he did not repent of the decision itself. To Voldemort, Snape was the necessary sacrifice. So he didnāt kill him simply for the sake of killing him. At the same time, he felt no remorse after Snapeās death.
Even though Voldemort regarded Snape as one of his best Death Eaters, Snape was still a Death Eater. And like every other Death Eater, he was ultimately a pawn beneath the Dark Lord; someone expected to take risks and, if Voldemort deemed it necessary, to die for the outcome of those risks.