Okay... So while I agree with all the rest of the fandom who want Arata to defend Banri's honor I want to say something even though I know that this series explores possible romantic relationship between adopted siblings. Which to be honest is just as gross as blood related incest. I got hooked in it because despite the harem situation I really really like that Arata is always responsible and behaves as a dependable brother to his siblings even when he gets flustered when his sister's come onto him. What I would personally like is that all the sisters realize that they only have platonic love for Arata and had it confused with romance because of the shitty problems each have in their lives as well as the fact that their brother is so dependable. I think the fact that all of them aren't blood related also plays a major role in that. Here's to hope that these siblings could get past this hormonal soup and live as family, supporting each other.