Who WAS the True Master of the Elder Wand?

[Carol]

No: HPFGUIDX 183950

Pippin wrote:
<snip>
> Thanks to Mike's brilliant observation about Dumbledore blasting a
spell through a door, I've realized that we did see the Elder Wand
failing Voldemort. If Voldemort had been the wand's true master, could
a simple door have saved Lucius and Bella from his wrath?
> 
> I don't think so. The spells should have gone right through it. We
do see the spells of the Elder Wand deflected when Dumbledore is using
it,  but only by magic. They aren't stopped by ordinary obstacles, and
they don't miss. 
> 
> Pippin
>
Carol responds:

I don't think that counts as the wand failing voldemort. It served its
purpose--killing a lot of people in his wrath--and *he* certainly
never thought (or Harry would have known), "The wand failed me! It
should have killed him through the door!" I doubt that we're supposed
to recall that moment in GoF (Mike did, but only after numerous
discussions, and he's the only one I know of who's thought of it). Not
only do we never see the wand actually failing him (it also, as I
said, creates Nagini's bubble and, as I didn't say because it's too
horrible, draws Snape into that bubble), but Voldemort himself doesn't
start thinking about the wand's supposedly not doing his bidding until
more than a month later (he finds the wand around Easter, which
appears to be in March despite the fact that Easter 1998 was in April,
and the battle occurs in May)--at which point, he attributes the
spectacular magic he's supposedly performed with it, unseen by us
except for the bubble and the killings, to his own superior
powers--but if it's that spectacular, how would he know the difference?

As for Dumbledore's spells not missing, that's probably his own skill
and power. DD defeated Grindelwald, a Dark Wizard at least as powerful
as Voldemort despite Voldemort's reputation (and a great deal more
sophisticated and intelligent than the upstart Voldemort, as indicated
in their conversation in the prison whose name escapes me at the
moment) *before* he acquired and became master of the Elder Wand.

Carol, who still thinks that this part of the storyline is
unconvincing and serves no purpose except to get Snape killed