ok, first off, learn the subject matter if there's going to be a semi religious theme to the game. The devil is typicaly considered Male, or HE, not "it" and his "angels" are all not in heaven. Second, there is no need for the story with how it works, clicky clicky dead, no story, no decicions, no playing a role.
getting better, still needs some realism tweaks though. Specops are NOT stupid enough to throw grenades into their own fir support that's been set up there for the whole fight.