Why can Xion use a keyblade?

Xion is assumed to be a Nobody though, meaning she has no heart. It's already been confirmed that she has a connection to Kairi and Namine, so invariably, indirectly through them she has a connection to Sora. This connection to Sora, whatever it may be--if she's a mixture of Kairi and Sora, if their hearts somehow meshed while Kairi's heart was inside Sora--this could result in her having the power to wield the Keyblade. It's highly unlikely that her ability to wield the Kingdom Key is related to her heart, seeing as how Nobodies don't have hearts. But then, there's also the possibility that Xion is simply using a fake Keyblade, as Riku stated in the scene where they interact outside Beast's Castle. To answer this question correctly, we need to know more about Xion and her connections to Kairi, Namine, Sora, and Riku.

She was a puppet created by Even/Vexen (Also the first puppet). She was give the ability to take and copy Roxas power and memories which is why she looks similar to Kairi. Xion (Like the replica Riku) have hearts, so Xion really wasn't a nobody in the first place. So numbers 1-12 never had hearts when they joined the organization (Roxas had Ventus's heart which is why he looked like him AND why he had emotions/ he was Ven) So Xion can only use the Keyblade because of Ven

It's like asking the question, why are sora and Riku and Roxas and alot more people able to weild a keyblade. Maybe it has something to do with their hearts.

i think xion is kiria's real nobody.

Well, Xion is in fact, not a nobody. she was an experiment created by Vexen, and her subject name was No.I. She originally didn't have a face, but then began pulling things from Roxas, such as the ability to use the Keyblade.

The reason why Xion can use a keyblade was becuase in chain of memories sora was put into a capsal. But not a time capsal. Its a capsal where namine is fixing Sora's memories. During this time,organization 13 was hacking into Namine's work in getting Sora's memories back.(play kingdom hearts:chain of memories and you will understand.)Then they created Xion. That is why during the game she has the same dreams as Roxas. So in that matter, that means Xion and Roxas relate to Sora.

Well, It is said in a few places that Xion is Kairi's official Nobody. So, i think that too because she resembles Kairi and Namine a lille bit and i agree with what Amarxlen said.

i think because Xion has a connetction with Sora she has a keyblade. ^_^

xion does look like kairi when she was 14

BECAUSE she have the memories of sora and a puppet of sora thats why

What MegaNerd said :3

xion was not crated by vexen if you played 358/2 you would know that xemnas created her out of sora's leaked memeroies.thus for giving her the power to use the keyblade.she took the appearance of kairi because was sora's strongest memerie at the time.the difference was that kairi's hair was parted to the left and xion's was pa the right and xion's hair was black.after awhile xion was taking to much energy from roxas making him really weak. xemnas only wanted one of them and so thats whwn the big battle happens between xion and roxas she was using the devices xemnas put in a few worlds to change her apperance also her weapon roxas ended up killing xion but she went back to sora saying that the memerioes of them will dissapear but they will be inside sora.the last boss was riku and roxas beat him the first time and riku beat him the next time using xehnort heartless and that begin's kingdom hearts 2

Well yes. The same as kairi can use one in sora's memories. So yeah.

The r all benders of the keyblade

She is a leak of sora memories namine was trying to put sora memories in roxas but some leak and started to go in her

this is real cause i have 358/2 days

Dude, just wiki it, I did and found out xion is a failed memory experiment who looks like kairi because that's soras strongest memory. She is just like replica riku.

She actually is using Sora's Keyblade because she is a replica of Roxas (made of Sora's leaked memories) so she has all of Roxas's abilities implying the Keyblade.

In my opinion why, she was supposed to be a replica of Sora(so said the manga) but ended up being a replica of Kairi since that's Sora's strongest memory. So I'm kind of saying that Xemnas copy pasted Sora's powers and gave them to her.