The Earth was once the target of Talpa, an evil emperor who tried to conquer it for thousands of years. He was thwarted, banished to the Nether Realm, and his armor was fragmented into nine distinct sets. However, he has now come back to take control of the Earth by regaining possession of four of these suits. The Ronin Warriors are the sole defenders possessing the other five, and they represent the only chance of defeating him.