Waterkeeper said::: Sighs :: The Kingdom Key is the TRUE form of the Keyblade. The keychain brings out the Keyblade's "true form and power." I assume that it is the starting Keyblade of every Keyblade Master....either that, or a Keyblade like Mickey's inverted one. I don't believe there is only one. So I don't see what the big deal is.
(By the way, in Deep Dive, the DWU had an inverted Keyblade, with a red band and a gold blade and a silver handle, while Mickey had a Keyblade with a blue band, and a silver blade, with a gold handle. Since it was just a concept, I doubt they were paying that much attention to the Kingdom Keys being used. I know that the town in DD is being used in KH2, but that doesn't change the fact that they started out as concepts.)
OMG!! i thought i was the ONLY one who saw that! thank god! another person with true sight!!!