Worlds Demonic Battlefront

Before, it was a peaceful earth. There were no powers. No one was special. There were no conflicts. Maybe besides a few wars here and there. Then it was opened. Demons came into our world. We fought back. We weren’t enough. Until the first person to awaken their manifest came forward. Its been over a hundred years since this war began. That is where we meet our main character, Konpeki Seiryu, who’s parents sacrificed themselves for him. With his “unknown” manifest, will he be able to drive the demons back? Or will inner conflict disrupt his journey?