Seriously I would like to ask, where is the wife of Columbo? Eh, pardon I mean sister of MC? So far they only talked around her, but it's like she never exists outside of that talk.
About crazy bully girl, I don't think her desire is so simple, I would not be surprised if her end goal was something like a netorare. She has pretty ugly personatily and I can't imagine why MC still hadn't let the girls resolve things with fists. If you can't stand up for your self, rely on someone who does that for you, it's that simple.
She seems like she is helping MC, but does she truly? She seems like a person I would advise anyone to stay away as far as you can from.