What happens in the ending of the manga Nana?

In future sequences, Nana K. is already a mother to a daughter named Satsuki and a son named Ren. Satsuki is a six-year-old child and Ren is her brother (since she refers to him as "Onii-chan," meaning older brother in Japanese which can also be used for older twin brother). Satsuki is a name Ren Honjo had chosen for Nana K. if the child she has is a girl. If the child ended up being a boy, Nana K. is unsure what to name him, since she desires to name her child after a flower, like Ren (one of the few suitable flower names Nana K. can think of for a boy). Ren's death, however, makes it seem likely that her baby was named after Ren in his honor while her second child, a girl this time, got the name as chosen by Ren. Although their family life is undoubtedly unstable and separated (with Nana K. and Satsuki in Japan and Takumi and Ren in London), Hachi is still willing to be married and Satsuki wishes her family to be together. Takumi and Naoki also have a conversation about how it must be difficult on their children to have their family separated, and that Ren (who is staying with Takumi in England) should not stay in a foreign country but go back to Japan. Nobu shows concern for Ren's staying with Takumi in England and not attending the fireworks with Satsuki.

Nana and Takumi's relationship is rather complicated: in the future, Junko is shown once trying to convince Nana to ask for divorce (which Nana refuses, stating that there are "many reasons why not to do that"). Nana acknowledges that although Satsuki wishes her family (Takumi, her, Hachiko, and Ren) to live together as a whole family, she will be unable to fulfill that wish as she cannot settle with Takumi unless the missing Osaki Nana returns.

Nana O. was doing interviews in Osaka to prepare for her solo career when Yasu informs Nana that Ren has died, and must travel to their hometown for his funeral. Although she attends, she becomes catatonic and is unable to speak during the ceremony. After the procession, Ren's manager brings in a birthday present from Ren that was found in his belongings and asks Nana to accept it. Nana silently moves onto a couch and lies down. The present remains untouched. In recent chapters, Nana O. had started getting panic attacks due to stressful situations, causing her to have trouble breathing. This usually had to be remedied by putting a bag over her mouth to circulate carbon dioxide and regulate her breathing. Hachi wasn't aware of this problem until Chapter 81, where she helped Nana's breathing giving her mouth-to-mouth resuscitation, providing her with oxygen.

Basically at the end, Nana K. is living apart from Takumi with her daughter, and Takumi is in England with their son. Nana K. has a photo of Nana O. singing with long blonde hair and that is her only clue as to where Nana O. is.

The band and Nana K. meet at apartment 707 every year at the fireworks festival to wait for Nana O.

The manga is on indefinite hiatus and I honestly doubt the author will ever pick it up again. Even though it is such a influential and popular series 🙁

Nana Manga

Nana Osaki

Not at all...they do mesh, but the manga will keep going, while the anime stops at the fireworks show. If you liked both of those, check out the Nana movies too -- same story, but somehow the live action really sets the story apart from the others....