In the war, a group of warriors called Ninku fought against the Imperial Army and almost anihilated it. But in the end, the Ninku lost and got shattered. After the war, the imperial army established themselves as the defender of the people with the help of propaganda. They also managed to get the people to think the Ninku were the villains and had started the war. Fusuke looks like a child but he is the former captain of the first Ninku division. His mother was taken during the war and after the Ninku were defeated, he goes on a journey…
Source: MAL