The Worst Witch
Mildred "Millie" Hubble is the protagonist of the series. She is a good-hearted, but bungling young witch-in-training, who never seems to get anything right. She is friends with Maud Spellbody and Enid Nightshade and has a strong rivalry with Ethel Hallow. It is Miss Hardbroom, her potions teacher, who calls her "The Worst Witch".
Grand High Witch
The Grand High Witch is described as the most powerful being in the world and is the only one linking the secret societies of demonic witches that exist in various countries, as they are not allowed to contact each other. The Grand High Witch's headquarters is a great castle in Norway, where she has a magic money-printing machine and lives with large retinue of special Assistant Witches, tyrannically ruling over all the witches anywhere and plotting ever more harm to children everywhere. The current Grand High Witch, who is unnamed in the book but is known as Eva Ernst (Miss Eva / Miss Ernst) in the film, is described as "the most evil and appalling woman in the world."