Antagonists confusion


I’m quite dimwitted 'cos I’m confused on the meaning of “antagonists” & “working for the other side” in Burning Empires. Would both be equated to either working for the Vaylen (in a “Human PCs” campaign) & vice versa? Or do antagonists not have to be working for the “other side” per se, just AGAINST the PCs (ie. an arch-enemy noble who would be against the Vaylen too, as opposed to a turncoat which welcomes 'em with an open skull)?

Thanks again

Anyone who’s working against the players’ interests is an antagonist, whether or not he or she is working for the vaylen.