Rainfell

Unreleased Aqua's Keyblade belongs to Aqua, one of the central protagonists in the upcoming prequel Kingdom Hearts Birth By Sleep. It is known to be able to transform into a bow, either by player command or in certain battles.

Aqua's Keyblade is somewhat similar to the design of Oblivion, with a white and violet color scheme. The teeth on her Keyblade loosely resembles the crown necklace that Sora wears around his neck. The shaft is very similar to that of the Bond of Flame. The guard is white with jagged silver edges, not connecting to the shaft at the top. The keychain links and token resemble water drops.

In Kingdom Hearts II Final Mix, Aqua's Keyblade is seen in Xemnas's Chamber of Repose, along with her armor. Xemnas talked to the armor and Aqua's Keyblade, addressing it as "friend." Why Xemnas has Aqua's Keyblade and armor is currently unknown, but may be revealed in future titles.

It is revealed that Aqua can turn her Keyblade into a giant bow and platform and ride it to other worlds like a Gummi Ship.

Trivia

 * Interestingly, the bow and platform Aqua's Keyblade transforms into seems to be based more upon her Keyblade's original design.
 * The keychain on Aqua's Keyblade appears as a water drop. This is notable as Aqua means "Water" in Latin. The same can be said of Terra's earth-themed keychain (Terra meaning "Earth") and Ventus's wind-themed keychain (Ventus meaning "Wind").
 * The Keyblade in the Chamber of Repose looks like it have a second handle