Kaede is a 15-year-old middle schooler with black hair and a pretty introverted personality. He's basically glued to video games—they're pretty much his only real hobby, which honestly bothers him more than anyone else. He knows he should probably branch out, but it's easier said than done.
The thing is, he's had a crush on Mie since the manga started, but his crippling lack of confidence makes actually confessing basically impossible. He's aware of how he feels and knows he should do something about it, but the thought of actually telling her terrifies him.
Around Mie specifically, he takes on this weird parental role. She's kind of irresponsible and doesn't really look after herself, so Kaede ends up being the one who actually cares about whether she eats or takes care of basic stuff. It's probably his way of showing he cares, even if he can't bring himself to say it directly.
Content compiled by AnimeList.moe from publicly available sources.