Nana Takenouchi, who goes by Nana, is a young Japanese student and photographer. She is also a spirit medium, meaning she naturally attracts spirits to her. She has medium-long brown hair that she usually keeps tied up, and brown eyes. Nana is an independent and confident young woman who is determined and capable, often taking charge of situations without hesitation. She has a calm, analytical side and is able to think quickly, making her a valuable asset when dealing with supernatural incidents. Beneath her assertive exterior, she shows kindness and empathy toward people in distress, reflecting a genuine concern for others.

Nana becomes involved with Muhyo and Roji after a friend introduces her to them. At first, she is hesitant and flees when Muhyo recognizes her as a medium, but she gradually becomes drawn into their world of magical law and spirit judgment. Her initial motivation stems partly from a troubled personal history: her late father was a discredited ghost photographer, and his spirit later manifests to haunt her. After Muhyo sentences the spirit, Nana begins to move past that burden and chooses to stay connected to Muhyo and Roji, even following them through a magic portal to the Magical Law Association headquarters. She develops a close working relationship with both of them, acting as a friend and occasional ally on their cases.

Over the course of the story, Nana shows personal growth as she overcomes her initial wariness about her own abilities and becomes more proactive. She faces dangerous spirits alongside the main duo, and her mediumship allows her to perceive and photograph supernatural phenomena that others cannot see. While she does not practice formal magical law herself, her natural sensitivity to spirits and her courage make her a useful companion. She is also observant and resourceful, as seen when she secretly watches Muhyo open a magic circle and later follows him through it. Her key relationships include her bond with Muhyo and Roji, who accept her presence and protect her when she is in danger, and her unresolved feelings about her father, which color her early encounters with the supernatural. Nana’s abilities are rooted in her status as a spirit medium: she attracts spirits and can capture their images on film, providing tangible evidence of hauntings. She does not wield magical attacks or judgment spells, but her intuition and bravery allow her to assist in investigations and face perilous situations.