Boax

A wizard who has suddenly arrived at the castle on a flying machine, and claims to have fallen in love with the princess. He is committed to marrying Arete. In fact, Boax does not love the princess at all, and only plots to kidnap her because a prophecy foretells that only she has the power to take away his eternal life. Boax changes her appearance to that of a more beautiful girl to persuade her father to allow him to take her away. He then imprisons her in a lonely dungeon.(wiki)