He was the "leader" of the group, always organizing events and stuff like that. When he realized he couldn't get away with everything, ie, that we didn't suck up to him no matter what, he started acting pissed at us. He couldn't stand people telling him to screw off or people confronting him for his crap.

He withdrew from the group, seeing us everyday at work but shitting on us, our events, and shit like that. He did this with everyone except one person.

Recently, he started going out again, but he's been acting extremely manipulatively. He's been trying to organize stuff only with those people that always say yes to him and purposely excluding everyone else.

The typical high-school drama behavior of "we are a tight clique and you all are fucked up". I don't know if those he's trying to pull on his side are actually aware of this, but I found a ton of Red Pill-like posts on his computer about going his way, how to be an alpha, what leadership means, and how to form his own group...

I don't like him, and I don't like what he's doing with people that are great to be around. Except for the single true friend he has, the others are great to be around. I'm in a position where I realize that I either step up my game to call him out or similar, or just let him get away with this...

And the reason this bothers me is that we are all working in a small company and all this social crap is started to get stressful since he began acting like a manipulative girl...

Would you act against him in my situation?