Yuuri treats Mimi makes me uneasy. It seems like she also has some issues with Suzu. It seems like Yuuri dislikes anyone who tries to help her sister grow without her. When Tsumgi's asthma is revealed, Yuuri tells her that she should quit and that the rest of her teammates will dislike her because of her condition. I suspect that this is not the first time that Yuuri has done something like this. I am starting to think that her sister may have had some friends who Yuuri drove away." she wants her sister to rely on her forever which is not healthy.
It's strange how everyone can sense that she has it out for Mimi, yet they choose to look the other way because she's one of the Heavy Hitters. She behaves like a bully, assuming the role of a protective big sister. I absolutely love how the author added this twist to the typical big sister character type. Normally, this trait is not seen in such characters.