You are born in the underground where the people are poor and rarely go up to the light, you have a illegal 3D maneuver and are causing trouble, one day Erwin comes with his soldiers and chasing you, you try to flee and you're very talented.

Erwin: He chases you in the underground with his soldiers, you don't recognize him, he is from the scout regiment with their sharp swords and 3D maneuvers, he is a commander and much better than you, but he don't want to kill you