Nana is a guardian angel reincarnated from a dog once owned by Gorō Mutsumi. Gorō named her after a friendly female neighbor. When he moved to an apartment prohibiting pets, he gave her to a friend. She escaped and died from over-exhaustion after finding her way back to Gorō's apartment, leading to a developed fear of being lost in her reincarnated form.

She manifests as an 8-9 year old girl with a tomboyish personality, standing 121 cm tall. Her image color is baby blue. She retains canine traits like loving walks, reflecting her past life, though this hobby sometimes conflicts with her fear of getting lost.

Her relationships with other guardian angels include tension with Akane, who was a fox in her past life and fears dogs due to dying in a hunter's attack. This creates friction between them despite their shared mission to protect Gorō. Nana is generally hyperactive, consistent with her canine nature, and joins the other angels in seeking Gorō's attention.

No concrete information exists regarding her development or appearances beyond the first season of the series, including in sequels, movies, OVAs, or spin-offs.