Keychains (キーホルダー, Kiihorudaa) is a piece of equipment that modifies the appearance and abilities of a Keyblade. It is a unique form of equipment available to every Keyblade. Most experienced Keyblade wielders possess numerous Keychains, which are indicative of a wealth of power and exposure to the worlds.
A Keychain is the crystallization of a Keyblade wielder’s accomplishments. Through performing specific tasks, establishing deep bonds or actions of such nature, the Keychain responds to the light or darkness that is formed from such actions and crystallizes itself as an extension of the Keyblade’s base Keychain. In doing so, the Keyblade may be equipped with this separate Keychain and possess a radically different appearance and set of abilities from the original Keyblade form.
More often than not, Keychains possess a unique elemental or magical characteristic that relates to the event that caused its appearance. They hold the ability to enhance specific Magic or Keyblade transformations, which enables the alteration of combat within an instant, given that Keychains can be switched by Magic.