This tall Frenchwoman has some fantastic magical powers, not the least of which is being able to conjure and talk to the dead. Yeah, she's awesome. Despite her tremendous intellectual and supernatural powers, in this novel, her most defining characteristic is her deep love for her husband, Nicholas Flamel.
In fact, her love extends to more than just her husband. She's a very compassionate woman—selfless, loyal, and generally good. While she is imprisoned in a tiny cell by Dr. John Dee's guards, she performs a spell that allows her to speak through Sophie and save the day, but at great cost. Here's how our narrator describes it:
There was one other thing she could do. Something desperate and dangerous, and if it succeeded, it would leave her utterly exhausted and completely defenseless. Dee's creatures would simply be able to pick her up and carry her away. Perenelle didn't think twice. (27.12)
She knows that her husband and the twins are in grave danger, and she knows she has only one chance to help them. The problem is, that one chance just might risk her life. But she does it willingly, with no thought of her own safety. She's like a fierce Mama Bear, willing to lay it all out on the line for those she loves. Perenelle's selflessness, loyalty, and unshakable love define her character, and contrasts sharply with fickle and disloyal characters like Bastet and the Morrigan.
Perenelle found out something amazing on her seventh birthday—that she could see ghosts. Instead of indulging her power to contact the dead, however, Perenelle made an effort to make herself invisible to them—crafting an aura composed of colors that the dead cannot see. She only indulges in her powers to contact the dead in an emergency, such as the moment when she realizes that her husband is in danger. Her modesty in using her powers except when they are needed by a loved one further emphasizes her selflessness.
You know you're powerful when the greatest magician and necromancer in the world is in awe of you. No one, not even Dr. John Dee, knows the depths of Perenelle's powers:
[She's] at least as powerful as her husband—in fact, there were some areas in which she was even more powerful. Those traits that make Flamel such a brilliant alchemyst—his attention to detail, his knowledge of ancient languages, his infinite patience—made him a poor sorcerer and a terrible necromancer. He simply lacked the imaginative spark of pure visualization that was needed for that work. Perenelle, on the other hand, was one of the most powerful sorceresses he had ever encountered. (6.6)
This is not a lady who messes around. She does what she needs to do to take care of her own and get the job done. In this description comparing her to her husband, we might imagine that she has the imaginative spark that her husband lacks. She's creative, compassionate, and capable. No wonder she's such a force to be reckoned with.