
The χ-blade is a legendary weapon introduced in Kingdom Hearts Birth by Sleep. Despite looking similar to a Keyblade, it is something "altogether different"; rather than being a man-made counterpart to Kingdom Hearts, it coexists with Kingdom Hearts. As such, instead of opening the door to an artificial Kingdom Hearts like the Keyblade of heart, it actually materializes the true Kingdom Hearts, a perfect union of all hearts and worlds. The Keyblade War occurred because of the many souls who desired to take the χ-blade and Kingdom Hearts for themselves, and Master Xehanort later enacts his plots with the same goal in mind.
Design[]
The χ-blade appears to be made up of two crossing Kingdom Keys, with the teeth facing outward. It has a filigree that slightly resembles one on the Ultima Weapon, and the blade slightly resembles the Dream Sword.
The incomplete χ-blade's coloring is more red-orange than bluish-yellow, and the blade is slightly covered with an aura of darkness. It also has chips in the side of the blade, lacks a part of the filigree on one side, and part of the Kingdom Key's hilt is missing, making it look somehow broken or shattered.
The Keychain is a black and red heart that is similar to the Heartless symbol, only without the fleur-de-lis bottom and jagged cross, with two Kingdom Keys crossed over it. The chain starts out as two separate chains that form into one.The Keychain's two crossed Kingdom Keys is reminiscent of the symbol of the "Keys to the Kingdom of Heaven". Although it is not seen in this incarnation, it is especially significant that the Kingdom Key has a silver blade and gold hilt, and the Kingdom Key D has a gold blade and silver hilt, matching the keys on the symbol. When the χ-blade hits a target, the released symbols are gold and dark blue stars, symbolic of light and darkness.
Although χ-blade is pronounced "Keyblade", the letter "χ" is the letter chi from the Greek alphabet. This is why the name of the weapon is spelled "χ-blade", but, as Master Xehanort explains, can be pronounced "Kye-blade". Master Xehanort explains to Ventus, with a visual demonstration of the ancient letter "χ", that he is not referring to a Keyblade that Keyblade Wielders use. He continues to state that the letter itself carries a meaning of "death" and that it "spells endings".