Fatal Crest

The Fatal Crest is a Keyblade obtainable in Kingdom Hearts II by completing the Goddess of Fate Cup.

Appearance
The neck of the keyblade appears to be that of a skeletal dragon, of which still has life in some of it. The token is the Hades Cup.

Trivia
The Valor Form edition of the Play Arts Figures comes packaged with Fatal Crest as one of the Keyblades. Ironically, however, Fatal Crest is best used for its magical capabilities--and since Berserk Charge requires a complete loss of MP, Fatal Crest is almost completely useless for Valor Form, since magic is sealed during it.

It gives the largest magic bonus of any Keyblade (except for the Winner's Proof, which is only available in Kingdom Hearts II: Final Mix+), making it good for usage with Wisdom Form.