Nazuna was the original user of the "If" ball to change fate, but it didn't work for her until it ended up with Norimichi.
- The first time we see it, Nazuna is picking up the glass ball at the beach. And it seems to be something related to her missing father, whose disappearance appears to have something to do with water. A lot of the first half of the movie sees Nazuna acting very listless and mysterious, often catching Norimichi's eye in the process. It's only when she starts talking to him, and in the timeline when he won the race, that she seems to perk up and become genuinely cheerful. It may be that Nazuna originally kept trying to change her own fate with the ball, over and over, to the point she was becoming hopeless at the thought of changing anything. Hence her early listlessness. At least until Norimichi manages to start making changes. One of the first times we ever see her express a louder emotion is when Norimichi tells her he became distracted during the swim race because of how fast she swam, and it psyched him out. To which she responds by looking shocked, and asking if it was her own fault he lost the race. Nazuna only noticeably becomes more bright and genuinely cheerful after Norimichi won. Maybe not only because she was happy he was the one who won the race, but because she was happy that something finally changed in her time loop.