Nana Osaki

The Japanese manga series Nana, written and illustrated by Ai Yazawa, features a cast of fictional characters of which the two main characters share the name Nana. The series chronicles their friendship and their lives as each chases her dreams. Nana Komatsu is a small town girl who goes to Tokyo to follow her boyfriend and college friends, with the hope of having her dream life. Nana Osaki was in a popular punk band in her home town. Nana Osaki's friends include her bandmates in the Black Stones (Blast) and her former bandmate who is involved in a band called Trapnest.

Black Stones — normally shortened to Blast (ブラスト, Burasuto^?) — is a popular punk band within the series. Ren was once a member of the group, but, after his departure to join Trapnest, they recruit a new member, Shin. They attract a large following, and ultimately sign a deal with Gaia Records. Nana Osaki is their main vocalist.

Trapnest or Tranes (トラネス, Toranesu^?) for short, is a popular band in the manga. Nana wants her own band to overtake Trapnest as the leading one in Japan.

People who have interacted with Nana K. personally at given times of her life. They do not address her with her nickname, Hachi, and have deeply affected her perceptions on certain situations. As they are not deeply involved with the two bands, she will often reflect on her experiences with them for reassurance when she is in doubt of her simultaneous loyalties to Blast and Trapnest.

Black Stones eventually sign a full contract with Gaia Records. Due to the tabloids' interest over Nana and Ren's relationship, Blast members relocated to one of Gaia's facilities and voluntarily shared housing with other talented individuals under Gaia's name.

Trapnest's official record label which is also a homage to the magazine that serialized the manga. Unlike Blast, members are assigned more managers who ensure that they meet their appointments and affirm each member's status.

A magazine that shares similar characteristics to the Japanese magazine, Friday. They are a part of the "paparazzi" that track both bands. When Blast was becoming popular, they were given a leak that connected Nana O with Ren and have not stopped from spreading negative (and sometimes false) information about them.

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Wikipedia