In the future, mankind no longer exists. The highly developed achievements and the richness of history and culture have already been lost for a long time. The only thing left is the broken horizon and the high self-awareness robots called S.T.E.E.L. These S.T.E.E.L. have developed a unique society and way of survival through self-learning without the guidance of previous masters. Although a wide range of destructive weapons is no longer available, the war neve ceases……