One-Winged Angel

The One-Winged Angel (片翼の天使) is a form of Sora's Keyblade. It is obtained by defeating Sephiroth at the Olympus Coliseum in Kingdom Hearts: Final Mix. In battle, the Keyblade becomes completely engulfed in flames when it is swung.This may be a referance to the Nibelheim Incident in Final Fantasy VII (also seen in Final Fantasy VII Crisis Core), where Sephiroth razed a village to the ground.

It is also available in Kingdom Hearts: Chain of Memories, along with Diamond Dust.

Appearance
The One Winged Angel resembles Sephiroth's Masamune sword, although its handle and blade differ, in keeping with the design of a keyblade. Its keychain is in the shape of a wing, hence its name, and the end of the blade bears a resemblance to the spell Meteor, which was a major plot device in Final Fantasy VII, the game that originally featured Sephiroth.

Trivia

 * One Winged Angel is named after the famous battle music played when fighting Sephiroth in Kingdom Hearts, Kingdom Hearts II and Final Fantasy VII. The name 'One-Winged Angel' refers to his Safer form from Final Fantasy VII. Despite resembling a Seraph, a six-winged angel, the title refers to the multi-colored wing that replaces his entire right arm.