So awoken are just that awoken they are a sub species that was put to sleep for colonization of a deeper solar system. But now have been awoken to help fight the darkness. Let's then go one further and say they are criminals, they committed crimes and were put to sleep (As seen in a little bit of the awoken in the clip he's an outlaw.) maybe as a byproduct of the freezing process they became white/blue/grey. I would love to say why they are a different species or that they are, but I can't. They could be relics of an old war (which I doubt as that's exo) or from the future. It's way to early to call.