Roxas's (and Xion's) Keyblade

[Odysseus]

So I've read and heard multiple theories on this, but I have no idea which one is right. Someone please clear this up for me.

Why can Roxas and Xion wield the Keyblade? Obviously, it's because Roxas is Sora's Nobody, and Xion is a replica based on his memories. But that means that they'd all be tapping into Sora's Keyblade. I can understand Roxas using it when Sora's asleep at the intro to KH2, but how can both Roxas and Xion wield it at the same time?

On top of that, there may be three of Sora's Keyblade, because both Roxas and Xion are going on missions while Sora's bonkin' scat up at Castle Oblivion (or maybe not: that could be when Roxas or Xion is knocked out, but I really don't recall when in the plot that was, and Days's messed up dates for Castle Oblivion don't help).

So that's two, possibly three of Sora's Keyblade being used simultaneously. I've read theories that say 1) Sora's Keyblade can exist at multiple places at once as long as they're tapping into the same Heart (Sora's), and 2) Ven has something to do with it. Roxas's dual wielding ability has also been credited to Ven, but I've seen something else saying it's because he defeated Xion. Blegh.

Can someone clear this up for me? Thanks.

 

[billyzanesucks]

#1 would be correct. As long as Sora's power is balanced between them, all three of them could use the keyblade. But Xion is basically just replicating the keyblade; even though it has the same powers, it's not real. Roxas's keybade is real.

 

[Joker'sHeartless]

Also, Roxas' dual wielding does come from his possession of Ventus' heart, but it was triggered when Roxas defeated Xion.

 

[Gram]

#1 would be nearest to being right you see roxas is essentially sora (his nobody=body+soul) since sora is technically in two places at once (sora=the heart, roxas=the body+soul) so is his power (the keyblade) simply put roxas is using sora's keyblade at the same time.
as for the duel wielding that is when roxas is using his (sora's keyblade) and basically borrowing vens (who's hearts is in him) at once. the borrowing of vens key wasnt the only influence on roxas either he seemed to have emotions and age as well however whether that was ven or cause sora was coexisting with him is not been cleared up.

as for xion, her keyblade was fake plain and simple riku said so and so has nomura. how it is fake yet releases hearts from emblem's isnt explained not that it really needs to be, she was meant to copy sora's power and she did as such.
and yes roxas awakened duel wielding cause of xion, tho its not for the reason people claim the loss of her put roxas in a emotional breakdown that called out vens keyblade.

 

[KeyofEvil'sBane]

Also, Nomura has stated that yes, Sora and Roxas can wield the same keyblade (Sora's) at the same time. Since Xion's is only a copy, all that matters for her is how much of Roxas's power she has absorbed

 

[Sephiroth0812]

So I've read and heard multiple theories on this, but I have no idea which one is right. Someone please clear this up for me.

Why can Roxas and Xion wield the Keyblade? Obviously, it's because Roxas is Sora's Nobody, and Xion is a replica based on his memories. But that means that they'd all be tapping into Sora's Keyblade. I can understand Roxas using it when Sora's asleep at the intro to KH2, but how can both Roxas and Xion wield it at the same time?

Roxas is in fact the only one who can use Sora's real keyblade, which is because he was born from Sora's heart when it became a heartless.
Roxas is a part of Sora and closely tied to him, that's also why Sora can explore Twilight Town in Chain of Memories despite never having been there. Roxas's memories are accessible from Sora's heart due to them co-existing they share a very close psychic link (which may also be strengthened by the fact Roxas carries Ventus's injured heart, which is also closely connected with Sora's).
Xion's keyblade is a sham, a fake, as confirmed by Riku (who examined it and knew instantly) and Nomura.
Xion was copying Sora's powers (and therefore the keyblade) by absorbing memories of Sora and also by feeding on Roxas's power.

On top of that, there may be three of Sora's Keyblade, because both Roxas and Xion are going on missions while Sora's bonkin' scat up at Castle Oblivion (or maybe not: that could be when Roxas or Xion is knocked out, but I really don't recall when in the plot that was, and Days's messed up dates for Castle Oblivion don't help).

So that's two, possibly three of Sora's Keyblade being used simultaneously. I've read theories that say 1) Sora's Keyblade can exist at multiple places at once as long as they're tapping into the same Heart (Sora's), and 2) Ven has something to do with it. Roxas's dual wielding ability has also been credited to Ven, but I've seen something else saying it's because he defeated Xion. Blegh.

Can someone clear this up for me? Thanks.

While Sora was doing stuff in Chain of Memories Roxas was indeed knocked out due to Naminé starting to mess around with Sora's memories, which affected and weakened Roxas.
It was also then that Sora's memories where scattered and due to their link some found the way into Roxas...and Xion could then start to absorb them to strengthen herself.

The dual-wielding is solely contributed to Roxas having Ventus's crippled heart within him. Xion has only indirectly to do with this as Roxas defeating her led to him awakening Ven's keyblade.

#1 would be correct. As long as Sora's power is balanced between them, all three of them could use the keyblade. But Xion is basically just replicating the keyblade; even though it has the same powers, it's not real. Roxas's keybade is real.

Exactly, that's also a reason why Riku was so surprised in the battle at memory's skyscraper.
At first he expected Roxas to use a fake keyblade as well and was caught off-guard when Roxas used a real one.
Due the question: "Why...why do you have the keyblade?"

Also, Roxas' dual wielding does come from his possession of Ventus' heart, but it was triggered when Roxas defeated Xion.

This. The short version of how it happened. Ven's keyblade was sealed away all the years his crippled heart was sheltered inside Sora and also while Roxas had it, most likely due to the excessive damage.
But Xion's defeat, like Anagram already pointed out, caused Roxas to have an emotional breakdown which was so intense he somehow unconsiously managed to access Ven's heart directly and awake/pull out the second keyblade which belongs to Ventus.

Also, Nomura has stated that yes, Sora and Roxas can wield the same keyblade (Sora's) at the same time. Since Xion's is only a copy, all that matters for her is how much of Roxas's power she has absorbed

Not only Roxas's power though, also much of Sora's own memories which are scattered due to Naminé's meddling around and some also found their way into Roxas (who can't do anything with it and doesn't associate them with himself since by now he has developed his own mind and personality independent from Sora).
These are also the "main" reasons both of them needed to be fused into Sora, because the memory-restoration could not be finished without the memories of Sora both Xion and Roxas hold.
In Roxas's case, there was also the issue of his physical existence based on Sora's body and soul which also needed to be given back, but that's another issue...