In real-time and turn-based strategy games where the player constructs units for use on the battlefield, it is often the case that you will have some units available at the beginning of the game that you cannot train more of, at least not until you have teched up. This is fair enough when you control nothing but a single base, given that they presumably were sent from elsewhere. When you control a entire faction from the start and you have units that you cannot actually build yet, it raises the question of how your faction got hold of them in the first place. Sometimes an inversion occurs: you are told that your faction or a particular region is famous for such-and-such unit and will get some kind of bonus to their construction, even if no such unit exists anywhere at the beginning of play