Χ-blade

The χ-blade (χブレード, Kīburēdo?) is a legendary Keyblade introduced in Kingdom Hearts Birth by Sleep. According to the Xehanort's Report, the χ-blade was an alternative method to opening Kingdom Hearts. As written in Report 7, he stated that "unlike the Keyblade, which existed to join Kingdom Hearts, the χ-blade existed alongside Kingdom Hearts." Presumably, Master Xehanort believed that lust for the power gained from opening Kingdom Hearts and thus the urge to create the χ-blade to open Kingdom Hearts was the reason behind the Keyblade War.