The broken blade: the reborn king

A reincarnated king, raised as a poor fisherman's son, is secretly trained by a wizard. He joins a knightly trial to rescue his kidnapped sister, wielding a rusted sword with great power—but faces doubt and persecution for his low birth. When he draws the legendary sword to prove his identity, the usurper makes a blood pact with a dragon to destroy him and the knights. The wizard sacrifices his life to retrieve a sacred blade, awakening the king's sealed memories and power. The returned king slays the dragon, ends the usurper's reign, then chooses to guard the dragon seal in the north, entrusting his crown and kingdom to his sister—fulfilling both royal duty and family bond.