Legend of Hero Tonma

This is a story of a time when the demon world and the human world were connected. Tonma, an apprentice of the wizard Merlin, is meditating one day when she hears a princess somewhere calling for help. According to Merlin, Tonma is a prince of a certain country, and he is destined to be united with that princess. Tonma sets off for the demon world to save the princess.