I have been musing about this for awhile but I would like your two cents. THough others think that Kairi and RIku being able to duel weild becaue of Namine and Repliku beiong aborbed by them Sora can duel weild because of his own and Ventus' keyblade. Roxas can duel weild because he is Sora's nobody. I want to think Roxas merely inherited the trait and even reabsorbed was not part of Roxas' original power set to begin with, he just happened to unlock it first. So they wouldn't be able to?
That sounds correct to me. The BBS Ultimania gives this:
Q4: Why can Roxas dual-wield?
A: Because he can use both Sora’s and Ventus’ keyblades.
Sora can wield two keyblades at once because he has Ventus’ as well as his own. As Roxas is a part of Sora, he also can use two. In Days Roxas awakened his ability to dual wield after fighting Xion. In KHII once Sora absorbs him, he can also dual-wield.
So Roxas uses Sora and Ven’s Keyblades and doesn’t technically have his own. Once he was reabsorbed, all he did was return Sora and Ven’s Keyblades to their owners, so to speak
It should also be noted that whether Repliku or Namine can even wield Keyblades is questionable. Namine doesn’t seem to be able to, but if she could I assume it would work the same as the Sora/Roxas situation, i.e. she’d just be using Kairi’s, and Kairi can’t dual wield her own Keyblade because it’s... just the one Keyblade
Repliku is really questionable, though. The only time we see him with a Keyblade, it’s that... I guess dream sequence thing Riku has when facing Anti-Aqua? And while Riku left Way to the Dawn for Repliku, we have no idea if that was more of a spiritual thing or literal. My assumption would be spiritual, in which case Repliku would only be able to use a Keyblade insofar as Xion can, which really just boils down to being able to make a duplicate Keyblade that’s not technically real. And even if it was a literal bequeathing... Repliku kind of ejected his heart from Riku at the end of KH3, so there’s no way for Riku to dual-wield. Riku’s window of dual wielding would be, like, the last three or so hours of KH3 and that’s it
