She has periwinkle colored hair tied into two pig-tails with black laces, and blue eyes. She wears a simple black-white dress along with frilly sleeves on her arms.
Nanami is cold and hostile at first, but she is soft-spoken and especially loves sweets and cakes. Being experimented on by the Vingulf for possibly years, she has shown naivety towards the real world, such as enjoying sweets and cakes, not knowing the worth of money as she had thought ten dollars would be a lot of money. Nanami is also willing to give up her money to a little boy, despite not knowing him, which displays her act of kindness.
Nanami was a Magician from the facility and was Number 5210 who was sent to find Kuroha and friends and retrieve them. She had tried to erase the memories of Ryouta and felt sorry afterwards, though she did not know it hadn't really affected him and he was acting it out. Sometime later Nanami becomes friends with the group and was happy to have her first friends. The facility had noticed she did not fulfil her task and they ejected her "harnessed" which ended up killing her. When she died, she erased all the memories of her from everyone except Ryouta as she knew they would be sad if she died and she wanted them to always be happy. She left a part of her inside Ryouta as she has fragments of information she wants to give him.
Powers and Stats
Name: Nanami Tokou, Number 5210
Origin: Gokukoku no Brynhildr
Age: Approximately 16 years
Classification: Magician (a hybrid of human and alien symbiote) class AA+
Attack Potency: Human level
Speed: Human, Supersonic reaction
Lifting Strength: Human level
Striking Strength: Human level
Durability: Human level
Stamina: Human level
Range: Tens of meters
Standard Equipment: None
Weaknesses: Her ability does not work against people wearing any kind of glasses
Nanami has only shown the ability of reading people's memories and erasing memories of individuals when looking at them in the eyes, and modifying or overwriting memories. It is an advanced ability though this does not work against people wearing any kind of glasses. It is also said in the manga that she has a hidden ability, which is most probably remaining in someone's memories even after death.
She can also manifest memories as tangible illusions, such as her appearance as Aphrodite and Ryouta's memory of Makina.