Kingdom Key

The Kingdom Key draws out the true power of Sora's Keyblade, even though it is not the strongest Keychain. As such, it is the true form of his Keyblade, which means that it is also the default form of Roxas's and Xion's Keyblades. The Kingdom Key is not wielded by Sora exclusively; Riku, Roxas, and Xion have also used it, and King Mickey is often seen wielding the Kingdom Key D, a color-inverted version of the weapon.