As a member of the rock band BLAST (Black Stones), she is seen wearing punk clothing and is normally seen with an electric guitar which carries on her back. When she is relaxed or not wearing punk clothing, she also has an element such as a rock band shirt. She is mostly seen wearing heavy amounts of make-up which include dark grey eyeshadow and dark burgundy lipstick her nails are painted black.
Nana's character is from another Anime, she is one of the two main characters in the series titled NANA. The other main character is her friend named Nana Komatsu, a hopeless romantic that is seen skipping from man to man because of various circumstances.
Nana at first seems to have a cold and rough personality but later on, it is shown that she has a good and kind-hearted side to her personality shown when trying to help Linda who was her Junior. She also shows kindness through her numerous run-ins with Banri such as the time he has a fever and she took him to the hospital.
She also dislikes it when she seems peoples who are in doubt.
She was once a member of the Japanese Culture Club Festival Research Society. It is said she later left the club because she was busy with her band.
She first appeared in a cafe where Mitsuo told Kaga Koko that he could not bear to with herko. After Koko falls into despair and sorrow, she tells Banri that she wanted to die and at that moment, Nana appears and gives her a ticket to her band's show, telling her "If you want to die, die with music".
After Koko and Banri show up at Nana's concert, Koko lets loose in desperation and climbs the stage. She then takes the mic from Nana. This make Nana upset and she told them that the stage belongs to her, before calling officers to get rid of them both.
The next time Banri, Koko, and Nana met was in the elevator at Banri's apartment complex. Nana saw them together in an elevator and asked if they were dating but Banri and Koko ignored her because they were scared of her. She became annoyed with them because she disliked being ignored. It was after this encounter that Nana became aware of Linda and Banri's unresolved issues with each other.
Nana found Linda one day crying over her and Banri's relationship and it was that point where Nana became aware of the relationship between Banri and Linda. She helps Linda by tricking Banri into thinking there's a leak in his apartment complex that might've affected his room. Once Banri rushes to his apartment, he realizes that Nana was the one that made the call about the leak and she was tricking him into meeting with Linda as he was avoiding her.
Banri learns that Nana was actually his next door neighbor and also that she was a senior and good friend of Linda's and they became closer throughout the series. Banri would sometimes bump into Nana, asking her for advice and for help. And later in the series, Banri became sick and Nana takes him to the hospital. She reveals to him that she really does care about others more than herself and she hates herself for not doing more.
Before her debut in Golden Time Nana Osaki's band
(Black Stones http://nana.wikia.com/wiki/Black_Stones ) consisted of three other members: Yasushi Takagi http://nana.wikia.com/wiki/Yasushi_Takagi Nobuo Terashima http://nana.wikia.com/wiki/Nobuo_Terashima and Shinichi Okazaki http://nana.wikia.com/wiki/Shinichi_Okazaki