The twin brother of Sophie, fifteen-year-old Josh Newman starts out working in a bookstore. He is known for his loyalty and cautious nature, often using logic to complement his inquisitiveness in unraveling the mysteries they encounter.

An ancient and cunning alchemyst pretending to be an ordinary bookshop owner named Nick Fleming. Nicholas Flamel acts as a mentor but is revealed to have deeper, hidden motives guiding his actions.

Nicholas Flamel’s wife known as Perry Fleming, who possesses strong magical abilities, including communicating with the dead. Perenelle is resourceful and supports the protagonists despite being captured by enemies.

A 2,000-year-old warrior who appears youthful and human-like, Scathach, also known as "Scatty," provides protection and instruction to the twins. Her combat prowess and cautious nature serve as key assets throughout the story.

The antagonist and one-time apprentice to Nicholas Flamel, Dr. John Dee is a nefarious alchemyst and magician serving darker forces. His quest for power puts him at odds with Flamel and the twins.