They were executioners, murderers and spies, martyrs at best, but certainly not missionaries. So it came off as a surprise when the Detective mentioned "those below", as if their Holy mission was bound to some abstract and futile notion of Justice and noblesse oblige. Because man... get the Arrows to swear Oaths and all that jazz.
The Guardians were zealots, and they had to be for the greater good. Someone had to get shit done while keeping the others from soiling their undies.
Their ward was Magic itself.
"Yo", he says, "you done with that?", he says while looking at the man but really just focusing on the oxymoron in front of him. Because at the end of the day their Order affiliation did all the talking. No matter the bullshit he could tell, he was a rotten cop, because if he wasn't, he wouldn't be a good Guardian.