Excuse me a moment, my wife is in the kitchen cutting some onions. Koharu is so lonely and Himari coming over is probably something she really looks forward to. Now she has Mizore to rely on and keep company, so this really worked out amazingly for her. At some point, Himari is going to get older and won't come over as much. Mizore could almost be like a daughter for her (in a weird kind of way, maybe more like a younger sister?) and give her a reason to want to stay in her mother's house.
Ok, the onions are gone...Himari is such a troublemaker lmao, she carried that head in a thermal lunchbox, went home presumably went to sleep and then woke up the next morning and took Mizore to school with her. This definitely can't end well.
Enjoy!