It is 2055. Dark, a mysterious character of unknown past, emerges in a world war. He's fighting only for hire and for each side of the conflict. Extreme power makes some people think that he's not a human. During the war he has never lost any battle.
Now after the war is officially finished he still fights. No-one knows his reasons.
Joint governments set up a reward for the one who'll kill Dark. Since recruits around the world don't want to split that money they have created a competition - League. Only the one who wins will have a possibility to beat Dark
Source: The Game Website.