Kingdom Hearts II What's up with that new black and white keyblade?

Not only is Sora using it in the video in which he fights the Knight (and dies in three seconds), but Xehanort's Heartless(?) is using it in the secret vid. What's the story significance supposed to be with that thing?

 

It'ss the keyblade you get from beating Roxas and I don't think the bald man is using it... looks more like a black Oathkeeper to me.

 

Look at it closely, it even has a chain just like the one Sora's using. I'm pretty sure it's the same one.

 

There's only two new keyblades in FM+, Mushroom Madness and uhhh... Roxas Zipper Blade. (Those names aren't official, I made them up...heh...) The blade Sora was holding looked nothing like the Mushroom keyblade i saw earlier in some magazine, so I'm pretty sure it's the Roxas blade which has to have something oreinted with or concerning Roxas...

 

it does look like the one Fake Roxas is Wielding ... if you exclude major details.
the the old man's key for a secod there it looked like Athena's Blades from God Of War... ( i just bought GoW 2 so now you know y i made that assumption) lol

---Khilango