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".
The Worst Witch
Ethel Hallow is Mildred's acid-tongued rival. She does very well in class, comes from a prominent witch family, and gives the impression of being a model student. However, she is spoiled, snobbish and vindictive although able to turn on the charm and act sweet and innocent when the teachers are near, playing the role of a victim with Mildred as the bully. Up until "The Worst Witch to the Rescue", she is Miss Hardbroom's favourite student; however, in the same book, she is exposed as a cheat and a liar, and thus has to watch her step lest she incur her teacher's wrath.