Keyblade War

The Keyblade War (キーブレード戦争) was a mysterious conflict in which many Keyblade wielders fought, featured in Kingdom Hearts Birth by Sleep. Neither the extent nor cause for this conflict are known. It is also unknown whether or not the Keyblades were real.

Those who possibly participated in this battle were Terra, Ven, Aqua, Master Eraqus, Master Xehanort and his apprentice, Vanitas; and possibly King Mickey. However, as the exact date of this event is unknown, it is highly possible that aforementioned people merely were at the scene of the event much later, not actual combatants or even witnesses.

In the TGS 09 trailer, Master Xehanort reveals that the numerous Keyblades in The Gathering Place are indeed the remains of the Keyblade War and the reason for the fight is between Light and Darkness. This indicated that the War indeed predates the events of Birth by Sleep.