Long ago, humanity lived in a peaceful kingdom ruled by a king. They lacked particular super natural abilities unlike other races, but they lived happy lives. However, they were regarded as nothing in the world due to their lack of  super natural ability.For some selfish reasons some races attaked their kingdom murdered,tortured and enslaved the humans together with the greatest demon race  which conquered their realm.The humans had no choice except to accept their fate. Despite this, they remained optimistic, believing that a hero would someday arise and save them form this cruelity of the world.