User blog comment:Valeth/Caster of SIN/@comment-32751919-20190422162325/@comment-32751919-20190423051840

I see, but that being said, if Archer is really his allies (or at least, he was), it look like both aren't really getting along well. Beside, look like you just confirmed that Archer isn't a "good guy" to begin with.

So, Caster is Chaldea allies or at least, perform a "enemy mine" to Chaldea. (Just like in SIN that you probably can solo with NPC QSH.)