Nana Takenouchi is a high school student and aspiring photographer with medium-length brown hair, typically tied up, and brown eyes. She frequently wears her school uniform: a white shirt, short blue skirt, knee-length blue socks, and brown shoes. Her figure sometimes draws unwanted attention.

Her early childhood included receiving her first camera from her father, a photographer. After Nana's mother abandoned the family, her father created fake ghost images, straining their relationship. This culminated in a confrontation where Nana accused him of losing his professional integrity; he suffered a fatal heart attack immediately after, leaving her independent. Two months later, ghostly figures began appearing in her photographs, prompting her to seek help from Toru Muhyo and Jiro "Roji" Kusano. Muhyo identified the recurring ghost as her father's spirit and revealed Nana's innate ability as a hereditary spirit medium, attracting and perceiving spirits. Her spiritual energy naturally draws supernatural phenomena, causing spirits to manifest during occult activities like Kokkuri when she is present.

Following her father's exorcism and purification via the River Styx, Nana forgave him and developed a close bond with Muhyo and Roji, becoming a supportive older sister figure to them. Her medium abilities led to her recruitment as an investigator by Page Klaus for the Magical Law Association, where she documented supernatural cases. During the Vector arc, she shoved Kenji Satou out of harm's way during a ghost attack, sustaining injuries but surviving.

Nana maintains a passionate dedication to photography, often carrying her 1990 Polaroid Spectra PRO camera with a close-up lens. She dislikes idle time and possesses skills in quick-draw photography and concealing cameras. Her preferences include enjoying Roji's tea, seeking photographic scoops, and visiting hot springs. She has her lingerie custom-made at specialty stores.