Radia Senki: Reimeihen

The story revolves around a hero who awakens in a field, without any memories of who he is or where he comes from. After befriending a magician named Darus and rescuing Princess Lefis of Ark from her crashed airship, he learns that the nations of Samara and Ark have been conquered by tyrants named Nova and Gadiss respectively. The hero is launched into a quest to protect the Princess, free the people from the villains' reign, and discover his identity.