The Elder Blade is one of the most powerful ancient Keyblades in the world. The only person who knew its existience is the maker of all Keyblades, Zandlis. The blade is just as mysterious as it is powerful because of its use and the ability to absorb energy from any living substance. Zandlis mentions that the only being that hone the abilites and the usage of the Elder Blade was that of the warrior who hold every keyblade in existance. (Unknown details if the warrior Zandlis is mentioning about either Terra, Ven, and Aqua)