I've noticed that throughout the series, the Ultima Weapon changes its form. Examples:
KHI/CoM Version
http://images3.wikia.nocookie.net/_...KH-UltimaWeapon.jpg/200px-KH-UltimaWeapon.jpg
KHII Version
http://images.wiki.wegame.com/i/Y6PJjkBr.png
KHBbS Version
http://images1.wikia.nocookie.net/_...BS.png/120px-Ultima_Weapon_(Ventus)_KHBBS.png
My question is, why does a keychain that carries the same name throughout the series change so much?
KHI/CoM Version
http://images3.wikia.nocookie.net/_...KH-UltimaWeapon.jpg/200px-KH-UltimaWeapon.jpg
KHII Version
http://images.wiki.wegame.com/i/Y6PJjkBr.png
KHBbS Version
http://images1.wikia.nocookie.net/_...BS.png/120px-Ultima_Weapon_(Ventus)_KHBBS.png
My question is, why does a keychain that carries the same name throughout the series change so much?