Nonoka is a middle school girl with shoulder length dark-brown hair, white skin, and violet eyes. She wears a white blouse with a vanilla jacket and a skirt.
Nonoka is a kind and supporting person who is more mature for her age by doing activities similar to a mother like housework and waking up Akari.
Nonaka was the second born of the Mamiya Family. During IU massacre of her family following their refusal to share their knowledge, Nonoka was poisoned by Kyouchikytou, which caused her to loose her eyesight later life. The result of the massacre fragmented her clan and forcing her and Akari on the run.
The sisters settled in Tokyo, hoping the big city and close proximity and association with the Butei Academy would deter IU agents from investigating their location.