Nicolas Flamel, the famed 14th-century alchemist renowned for his expertise and authorship of texts like the "Livre des figures hieroglyphiques," achieved eternal life through the creation of the Philosopher's Stone. Within this narrative, his immortality is presented as fact. Flamel acts as a wise and powerful mentor to Montmorency, advising him on his quest to save Jeanne d'Arc. He provides Montmorency with initial alchemy training and instructs him on using the Philosopher's Stone to heal Jeanne's wounds, accompanying him on the journey while offering guidance and support throughout their shared mission.

Personality-wise, Flamel exhibits analytical thinking and intellectual curiosity. He demonstrates a preference for theoretical problem-solving and independent methods, consistently leveraging his extensive knowledge to advance objectives. His behavior suggests a focus on introspection and unconventional approaches, while maintaining engagement with events and people relevant to his interests, reflecting characteristics associated with the INTP personality type and Enneagram Type 5.

Flamel's actions consistently support the protagonists' goals, particularly in safeguarding Jeanne and maintaining balance through his alchemical prowess. His expertise proves pivotal during critical events, including protecting the Philosopher's Stone and interventions that influence the war's trajectory, dedicated to understanding alchemical mysteries.