Uta could arguably be called a yandere for her words and actions throughout One Piece Film: Red. She can be sweet and caring, but she can also be possessive and even destructive in a lot of very unhealthy ways. If she were to have her way, she would have been a danger to herself and everyone she cared about.
To clarify, Uta isn't a yandere in the romantic sense. She's more like a shock yandere, one who displays romantic yandere traits towards someone they care about but has motivations besides love. In Uta's case, her treatment of her worldwide audience was the result of past trauma and isolation, but there will be time to cover that later. For now, here's a look at some of the things she did in the movie and how they might make her a yandere.
What Yandere Traits Does Uta Have?
At first, it was hard to tell that Uta had darker intentions than even she realized. She came off as a cheery and benevolent songstress hoping only to please her fans and anyone else listening to her concert. She might have had a few emotional hangups about the state of the world, but nothing that would stop her from trying to bring everybody joy. However, as the movie progressed, the depth of her troubled mindset became far more apparent.
Uta's real plan was much worse than anyone realized, even Uta Herself. Her concert was actually just an illusion created with her Sing-Sing Fruit powers. Her plan after putting everyone in the dream world where nothing could go wrong was to eat the aptly named wake-shrooms until she died from exhaustion. Once this happened, her dream world would be cut off from reality and everyone's souls would remain there forever. This is to say nothing of her justification for essentially killing herself and all her listeners. Her dedication to this cause was harmful to herself and others.
Uta attacked anyone who tried to stop her concert. This included not just pirates like Luffy, but also the Navy, a Celestial Dragon, and even audience members who wanted to leave. She assumed that she could give them whatever they wanted, including freedom from suffering, but many of them just wanted to go home. Instead of releasing them, she doubled down and tried to make things more fun. This choice shows just how immature and close-minded, and overprotective she was being on the matter.
As Uta continued to lose control of the situation, she resorted to unleashing the demonic entity, Tot Musica. Besides how hypocritical this was to her cause to end suffering, it revealed a darker and scarier side to her than anything she'd shown before. By this point, she resembled a yandere in words, actions, and appearance.
Do Uta's Yandere Traits Make Her Less Likeable?
In fairness, it's not as though Uta didn't have her reasons for acting out like this. As a child, she was seemingly abandoned by Shanks on an island he'd supposedly plundered. She spent the next 10 years cut off from the outside world save for a man named Gordon. She'd only had two more years of contact with the outside world through Video Transponder Snails. Even then, it was mostly her fans reinforcing her views that she was some sort of savior from the suffering pirates cause. That kind of isolation isn't good for anyone's mental health.
It's also worth noting the influence of the wake-shrooms Uta was eating throughout the movie. Symptoms of eating these mushrooms include irrational and aggressive behavior. Uta had been eating wake-shrooms since before the concert started, so most of her yandere moments in the movie can be attributed to them; whatever negative impulses she had were probably magnified to the point where she felt the need to act on them.
None of this justifies Uta's yandere actions. but it does explain how she ended up as she did. The combination of a traumatic past, a sheltered life, and the wake-shrooms clouding her judgment probably led her to make all sorts of misguided conclusions and poor decisions. However, whether she can still be empathized with after threatening to trap roughly 70% of the world's population in a dream world is highly debatable. Whatever her reasons, she could definitely be called a yandere in this movie.
At the very least, she went far out of her way to make up for her mistakes. She sang one last beautiful song to wake everyone up before giving in to her exhaustion. In the end, all she ever wanted was for everyone to be happy.
Despite her flaws, Uta remained a fairly charming and well-meaning character throughout One Piece Film: Red. She displayed some bad yandere traits, but they were at least understandable enough to keep her from becoming unrelatable. She was also willing to learn from her mistakes and make up for them, even at the cost of her well-being. If she is a yandere, she's on the better end of the spectrum.