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".
List of minor The Worst Witch characters
Sybil Hallow is the bumbling but well-meaning younger sister of the vindictive and stuck-up Ethel Hallow. She is shown to be a lot kinder than Ethel, doing anything to impress Mildred and trying to make Mildred her friend, such as attempting to rescue Mildred's bats after they were mistakenly assumed to have been locked in a chest.