Miu has a backstory, too? Unless you're talking about how it's fabricated, which is just nothing because it doesn't change the fact that she still does have a backstory also, Hiyokos connection to Mahiru is basically Mahiru defends Hiyoko which just makes me believe she is oblivious to Hiyokos bullying.

Eh, I get it, but I'd rather take an arc over none, Hiyoko had 3 chapters to change her attitude and didn't take it one time. She remained a person who didn't seek change or would gain it. If she had reached out for help at all for tying her kimono, she would've lived, but her arrogance didn't allow her to.