In my venture into Asian TV, I got interested in the manga series/books that many of the Japanese Dramas were based. Nana was one of those series but the author due to illness has stopped writing. There were enough flash forwards in the series to conclude a few things about possible endings and some were even written by others in Fan Fiction.
To complete the series for myself, I made my own conclusion: After Ren’s death, Nana O disappears and Black Stones disbands. Nobuo goes back to his hometown to work at his parent’s Hotel. Shinichi becomes an actor. Yasushi becomes a full time lawyer and continues his relationship with Miu. Nana O disappears and Nana I (Hachi) gives birth to a boy that is named Ren. Takumi becomes a music producer/manager as Trapnest disbands. Takumi becomes Layla’s manager and she continues to sing. Hachi goes into business with Miu and a detective is hired to look for Nana O.
Two or three years later Hachi has a girl with Takumi and this time there is no question of paternity. Naoki who stays a drummer with a different group, marries and continues his friendship with Takumi. Takumi spends a lot of time in England for work and has an apartment that his son Ren comes to stay during vacations.
Hachi, Yasushi, Shinichi and Nobuo stay friends and continue meeting at apartment that the Nanas shared. Nana O ends up in London and detective finds her singing at a club. The marriage of Hachi and Takumi had its ups and downs but they stay married with Takumi spending much of his time in London. Hachi comes to London and reunites with Nana O. They return to Japan and the series ends with a reunion concert.