Okay. I was playing Birth By Sleep as Aqua when she ran into Terra at Castle of Dreams.

 

But here's my question: We all know that Terra and Master Xehanort wield Key Blades....but why is it that even after they become Terra/Xehanort that their Heartless and Nobody do not wield a Key Blade?

 

Just an interesting question that I'd thought I'd like to share.

that is a really good question, maybe they don't remember it or something, but then again roxas didn't know he had it but got it. maybe terra's hart was rapeling it

I think it is because the keyblade of light, which is what they hold, can only be wielded by people with pure hearts. However, as I am sure that you would point out, Xehanort and Vanitas carried keyblades as well. I believe that they are keyblades of darkness. However, I believe that Ansem, Seeker of Darkness, and Xemnas could not wield the keyblade because their original being succumbed to the darkness, just as how Riku 10 years later would lose the keyblade

I think right after the battle with Aqua and Terra-Xehanort,Aqua had made an attack that pulled Terra-Xehanort to the darkness and also relieving his keyblade powers(this is just a theory).

I think right after the battle with Aqua and Terra-Xehanort,Aqua had made an attack that pulled Terra-Xehanort to the darkness and also relieving his keyblade powers(this is just a theory).

 

Yeah I remember that kind of happening in a cutscene.

 

Well Terra/Xehanort falling back into darkness and Aqua jumping in after him.

 

So your theory might very well be what happened.

 

Maybe more light will be shead on this topic in a future game.

Well from what I've read I've learnt that [Final Episode Spoilers]

 

At the end of the Final Episode when Terranort turns the Keyblade on himself (I don't know if it was Terra or MX's will) he actually seals both Terra and MX's heart within himself along with both Terra and MX's memories except for the name Xehanort.

 

This could be potentially why Xehanort, his Heartless, and his Nobody are unable to wield the Keyblade.

 

because they don't remember how to/no longer have the ability to.

 

AznJeffxD is right. Master Xehanort, Ansem Seeker of Darkness, and Xemnas cannot weild the keyblade because they have no recollection of how to summon or wield the keyblade.

You need to have a heart in order to wield a keyblade. Light or dark doesn't matter what matters is a strong heart. Neither Xemnas nor Ansem the heartless have hearts so that (probably) why they cant use a keyblade.

But Roxas didn't even know about the Keyblade at all, still it came automatically when Roxas was in danger.

 

My guess is: That Roxas can wield it because Sora (Who is Roxas true self) still had his heart, unlike MX and Terra, who eventually lost theirs, to the darkness, during an experiment.