Oh wow. I'm shocked there's a reveal of such a big villain as fast as this, but I really like the progression shown here. Uichi was beat down by standing up for others but getting hit both by their backlash and the backlash orchestrated by this insane kid. Cause Uichi didn't have any good reason to be bullied. He was shown to be pretty much a stand up guy who does well in school and was friendly and open to others when he was younger. His house life is a mess, but his tormentors never brought that up. Instead, it almost seemed to be ancillary to what he was going through.
Now we see what's gone on: he got painted as a fake stuck up asshole who's only pretending to be a good guy, so people didn't really give a shit when the standard bullying things started happening to him. All orchestrated by this insane kid.
I have a feeling we're going to see a fatality soon. I'm pretty sure Yotsuha could get this kid to jump off a building if she asked him to.