* Marcia Overstrand is Septimus's best friend. She is a kind and caring girl, and she is always willing to help Septimus when he needs it.
* Alther Mella is Septimus's mentor. He is a powerful wizard, and he teaches Septimus how to use his magic.
* Mrs. Wetherwax is the caretaker of Septimus's orphanage. She is a strict but fair woman, and she loves Septimus like her own son.
* Simon Heap is Septimus's older brother. He is very intelligent, and he is always eager to learn new things.
* Jenna Heap is Septimus's older sister. She is kind and caring, but she is also very shy.
* The ExtraOrdinary Wizard is the ruler of the wizarding world. He is a powerful and wise man, and he is always looking for new ways to protect the world from evil.
* The Dark Wizard is the main antagonist of the series. He is a powerful and evil wizard, and he is always trying to destroy Septimus and his friends.