Garry’s Mod is a sandbox mod for the Source Engine. Unlike normal games there aren't any predefined aims or goals. Players are given tools and are left to entertain themselves. The player is in a world where objects can be created and destroyed on demand. Where people can be created and destroyed with the click of a mouse. A world made for him. A world he made.
Because playing as spy in TF2 is too mainstream
Then I guess the SAS is the Pyro.
That would make perfect sense.
But wait, wouldn't the Phoenix Connection terrorist would fit the Spy more. I mean he does have a mask that resembles the Spy's. And Guerilla Warfare as Heavy. Arctic Avenger as Sniper. Gign as Soldier. Elite Crew as Demoman. Seal Team 6 as Scout (I think).
Well, at least we got a bright picture here.