First encountered in The Wonderful Wizard of Oz as the ruler of Oz, he leaves Oz in that book, and returns in Dorothy and the Wizard in Oz to live there permanently. The rightful hereditary ruler Princess Ozma having in the meantime been restored to the throne, he becomes an apprentice to Glinda, the most powerful magic-worker in Oz. Ozma decrees that only he and Glinda, besides herself, are allowed to use magic.