Rondo of Swords

During an attack on the city of Bretwalde by an invading army from the Grand Meir Empire, Prince Serdic was mortally wounded, so he had his body double take his place and save the kingdom in his stead. The new "Serdic" leads the few remaining soldiers of Bretwalde in a campaign to recapture their homeland and to drive off the Grand Meir. (TVTropes)