Fuuka Yamagishi
Fuuka was seeking out Mizuko because she was hoping that she could convince the Koi Fish to train her in the art of offense. She saw Mizuko like an upgraded version of herself as a wrestler. Both were insanely resilient and durable, to the extent that submission holds seemed to have almost no effect on them at times. But unlike Fuuka, Mizuko was actually capable of dishing damage back out onto her opponents.
Furthermore, Mizuko was a woman who didn't just beat her opponents, she hurt them. Admittedly, that wasn't something that Fuuka herself wanted to be doing to other people, be she thought that with her brand sheer impotence on offense being the starting point, she should try to find somebody vicious, who holds nothing back, to try to draw something out of her. And Mizuko fit that bill.
There was a rather glaring flaw in Fuuka's plan, though, actually convincing Mizuko. The Koi Fish was commonly described with very nasty words, none of which lent themselves to making people think that she would want to mentor anybody. But Fuuka had more experience than somebody her age probably should at interacting with people who had an... antagonistic disposition towards her, and the techie believed that if she could get an incredibly skilled yet socially shunned individual like Mizuko to help her, then she might be able to learn moves and techniques that nobody else knew or were ready for, because they hadn't been shared with anybody else. Fuuka saw real potential in having Mizuko as a teacher, so she was willing to put in the effort and push through the challenges if that's what it would take to even get her to say yes.
After a bit of searching, Fuuka spotted the splash of bright orange that she had been searching for. She had been told that Mizuko usually trained at this gym at this time on this day of the week, and it seemed that Fuuka's informant (Shiori Takeda; who else?) had been spot on. Seeing that the Koi Fish looked to be between exercises, Fuuka quickly approached and tried to strike up a conversation, "Um, excuse me, Mizuko Kajiwara? Could I please speak with you for a short while? I'm Fuuka, Fuuka Yamagishi. Another wrestler here at LAW."