The Deathcailbur (in Japanese: デスカリバー Desukariba) is the magical sword wielded by the Black Knight.
It can fire magical energy bolts, transport King Arthur, and summon creatures from the Underworld. In many respects, it can be considered the polar opposite of Caliburn/Excalibur.
It is indicated by Sir Gawain that he had never seen Excalibur, so it can be assumed that this sword is not a transformed Excalibur.
Regardless, Deathcalibur still maintained it's physical presence despite the split, but was as much of an illusion as King Arthur himself. After obtaining Deathcalibur, King Arthur used it for things such as summoning the Knights of the Underworld and combat.
Deathcalibur disappeared along with King Arthur when Sonic killed the corrupted king. A couple of copies of the Deathcalibur are used by the Dark Queen when fighting Excalibur-Sonic, but is also destroyed.
- The only time its name is stated is in the Faraway Avalon boss fight, when the Black Knight says "You blue pest! Roar Deathcalibur!" Its origins are unknown. It disappeared along with King Arthur when Sonic killed him.