The Third Great War was a cataclysmic event that set the stage for the global take-over of the power known as the World Union. Little is known at this time of the exact events of the War, but it left behind a legacy of pollution, toxins and genetically altered soldiers scattered over the world.
During this time vast advances in human science were made. The improvement of cybernetics led to the creation of the first biomech soldiers to fight increasingly brutal battles. But even this proved to be insufficient as the death toll grew. So the governments turned to cloning technology and bred their soldiers as Replicants or turned to DNA splicing to create hybrid warriors and assassins such as the Neko.