: A bubbly, naive 20-year-old who moves to Tokyo to be with her boyfriend, Shoji. Nana Osaki nicknames her "Hachi" (after the faithful dog Hachikō) because of her dependent and kind nature.

The anime and manga provide different levels of closure as the series remains on an indefinite hiatus due to the author's health.

: The series concludes with several unanswered questions, showing a future where Hachi and her friends gather at their old apartment, still waiting for Nana O., who has gone missing.