Wasn't sure where to put this. He is a mainstream rapper, just not in the US.

He considers himself Ajoessi rap. Ajoessi is just a name for middle-aged men and a certain personality. Not sure if I agree, but the music slaps. He just started a label and dropped "Breathe 3"

중2병 means "Second year middle school syndrome" and it basically means you don't give a fuck and do whatever you want. Like a 2nd grade middle school student.