The Heroic Legend of Arislan (1991)

Young Prince Arislan believes he is the rightful heir to the throne, but is he? The mysterious masked usurper claims that Arislan's father stole the crown from his father. Arislan must prove himself a worthy monarch, but his allies are failing him. Can he form an alliance with the young prince of a neighboring country? It requires a duel to the death with a great monster!