Blair and Camden get into a huge fight over Emma

Camden gets into a "relationship" with Emma, technically his first girlfriend so he doesn't really know what to do, and he begins ignoring Blair.

Camden starts canceling on Blair everytime they want to hang out to go out with Emma, Blair gets annoyed with this and is upset that his best friend so easily pushed him to the side so he calls him out and tries to talk to him.
Emma has been telling Camden that Blair is bad for him and a toxic friend and that he should dump him, so with these thoughts in his head when Blair confronts him he does not react well.
Camden says that Blair is just jealous of his relationship because he can't get a boyfriend, and keeps attacking Blair as hes trying to talk to him until hes forced to start attacking as well.
The fight gets blown way out of proportion and they both attack things they know the other is insecure about, they aim to actually hurt each other.
The fight "ends" when Camden brings up Blairs last boyfriend, his ex Onix, a boy he dated sophomore year and has never dated since they broke up.
Blair gets extremely upset at Camden for bringing him up, a topic they both know is off limits no matter what the situation is, and says something about Camden's family, an equally off-limit topic, before storming away and going home.

Blair and Camden equally ignore each other, Camden hanging out basically exclusively with Emma, and Blair making a new friend in Bonnie and confiding in Onix when they are heroes. The only person happy with this situation is Emma.