3000 Years Ago the boarders of the Realm In-Between was sieged by radical Light Keyblade Masters who wanted to overthrow the Darkness and destroy anyone whom followed it, the main order at the Land of Departure abandoned the radicals to do what they wanted while neither backing nor stopping the purge, then Emperor Allias Dark led an Army of Dark Keyblade Wielders and other Warriors out to stop them. Needless to say that it was a grueling task, it was much like dealing with a fierce Resistance force, it took years to kill them all off with some becoming mass murderers however by the time of their defeat many were dead.