A weapon which guards Kingdom Hearts. After the Keyblade War, it was shattered into twenty.
The X-Blade guards Kingdom Hearts. People wanted the light. They created replicas known as keyblades. The clash broke the X-Blade into twenty pieces: Seven of light and thirteen of darkness. The break made Kingdom Hearts get covered by darkness. Xehanort is interested in the war and wanted to recreate it by finding the Princesses of Heart and dividing his heart among 13 vessels.