User blog comment:B1littlehero/Speculation of the Origin of Species/@comment-24013204-20140611172200

I have a lot of interest in the synthetic Exos as a player class. They were, as you said, probably man-made, and have reached a sort of "intelligence", each being an independent individual. However your theory is quite a stretch, how they get their memories taken and have nothing to live for. I mean, that's a great use of imagination, but nothing has pointed to this with credible evidence. My theory is a little more simple. The exos were man-made synthetic life forms that were used to stop riots and insurrectionist groups against the Golden Age government, or maybe the City, or the Traveller or whatever (I don't have enough evidence to show a detailed theory). This has been a previously shown idea with the Spartans in Halo, since they were originally used as supersoldiers against rebel groups of the human race. As shown in many futuristic novels and movies, and even Bungie itself with the Forerunner AI in Halo, the Exos fight against their masters. Obviously they either win for freedom of their race, they both reach an agreement on the Exos rights, or the Exos lose and are confined to the wishes of their human creators, which, in turn, would possibly explain why they are guarding the City. This is, however, a theory, so you can debate whether it could possibly be the true backstory of the Exo race.