@FredFriendly Yeah I find him annoying as well. But Nega's reaction towards his antics are hilarious. I wonder if the author could've written out the brother without the need to be annoying. With that said his character just got introduced and it ain't fleshed out yet (ergo is he really a siscon or just protective?).
I like how the mangaka actually acknowledges that, yeah, this is a common thing in dealing with the brother. This has happened before and people are aware of the situation. It's a nice change of pace.