I've got an idea. Anyone ever heard of the Refugee Paradox, or the chronological collapse scenario in regards to time travel? Basically, it's this: If there is time travel, where the hell are all of the time travelers? Well, if we had it, they'd show up pretty damn quick. See, eventually, there's (most likely according to doctors in Astrophysics that are waaay more intelligent than I am) going to be an end to the universe. Protons are going to decay into more elementary particles, etc etc., and any civilization that creates time travel is going to come face to face with that harsh reality eventually. Of course, they aren't going to be happy about the end of everything, including themselves, so they would want to do one of two things: 1. Bring back their own hyper-advanced civilization and technology to the past, creating a large group of temporally displaced "time refugees" that would pretty much show up almost instantaneously after the advent of time travel (or hell, even before, because why not?). 2. They would send back a large repository of their technology with a large library of information and self-automated systems to attempt to turbo-boost their genetic ancestors in the hopes of coming up with a solution to the dire predicament of the universe (such as the ability to create openings into alternate, stable or growing realities where they can continue to thrive). It would be like seeding themselves for their own advancement and survival, and the ultimate expression of the survival imperative: I will outlive even creation itself. I think that Destiny could be a combination of the two ideas. We, some time in the future, became so incredibly advanced as to master time. We had, by that point, come into contact (friendly and hostile) with other advanced civilizations, and have a long and storied history (future history?) with them. Maybe we are dominant in the future; I actually like to think that we aren't, and have, over the course of our future history, been enslaved or vastly threatened many times. It builds a cultural and species environment of pragmatic survival, and roots out or creates a disincentive for individual or even cultural honor, at the expense of the greatest, highest good (whatever we have determined that to be at this point). Only thing is, we probably(definitely) aren't the only ones with access to this tech. Obviously the Vex have it. Perhaps all of the other species got hold of it too, or were caught in whatever aftershocks happened when we humans activated it to send the Traveler back to their own past. See, that's what I think the Traveler is: an ark of our future's memories and discoveries. How else could something we would consider to be so alien attune itself to us so perfectly, and seem to be so benign? How it uplifts the Guardians? Why it chose to save Earth? It was meant to be an agent of advancement, but turned into a grim protector for the future's sake. Well, why didn't the future humans send it back even further, and give themselves a huge head start? I think it might have been because our future selves knew that our enemies (more on that in a minute) might gain access to this tech, or piggyback to the past. This would create an unacceptable situation in which hostile forces with massively advanced weaponry and defensive capabilities would come and overpower a woefully primitive human species (think laser guns against spears). So, they sent the Traveler back far enough to get an advanced edge in terms of technological advancement, but not so far back so to render the denizens of that time helpless from hostiles. But what about all of the enemies? Well, there's a number of things to think about there. Maybe they're trying to settle old grudges by exterminating their foes before they even become threats. Maybe we are actually the bad guys in the future, conquering and enslaving all but the handful that escaped into the past. My personal favorite is that if the other species knew what the humans from the future were doing, they wouldn't even be enemies. Perhaps, in our glimpse of the inevitable, we decided to shift all of our priorities and focus on this one, over-arching goal. Not just for us, but for the good of all life in the universe. We would ignore anything that doesn't forward that goal, and eliminate everything that slows it down, regardless of whether or not it causes damage or death. After all, what are a few hundred, or thousand, or million, or billion lives when weighed against the absolute continuation of existence, for all races? If we are so far ahead, would we even want the other civilizations help? COULD they even help, even if they knew what our goals were? This gets into a grand idea called cosmicism: the universe has purpose, and great destinies are forged, but some beings are just so far behind that they simply can't comprehend it, and because of their limited frame of reference, misinterpret the great good's actions and immediate consequences as evil, because they fail to see the greater picture. These enemies might have had horrible things done to them, but no real harm was meant. It's like killing a termite hive that formed where you are building the ark before the flood (no religious implications meant here, just a halfway decent metaphor): the termites need to be stopped for the good of every other living thing, but they don't understand that. All they know is that they are being wiped out, with no concept of why. And so, we have a large assortment of misguided enemies, itching for revenge against their ultimate rescuers the humans, who don't even know that their Destiny is to be the saviors of life.