So ever since before Destiny came out, I've been wondering, what is the Darkness? Is it an actual entity, or is it something else? My current theory is that it is a metaphor for Death, because when the Darkness came most of humanity died out at the hands of the Minions of the Darkness. I believe that the Minions of the Darkness (Fallen, Hive, Vex, and Cabal) are just the bringers of death, and that the Darkness is the embodiment of this imminent threat of death for humanity. Something used to visualize our enemy as one threat, something that is the opposite of our Protector, the Traveler. The Traveler brings (and embodies) life, and the Darkness brings / is death. The only kink in my theory (that the Darkness is a metaphor instead of an actual entity) is the Heart of Darkness. The Heart of Darkness is a major unknown which is only able to be explained as being the Darkness itself, but I think it is something different. The Vex appeared to be at war with us for a long time, but if the Heart of Darkness was such an imminent threat, one would assume that it would be relatively new threat, compared to everything else. They have been fighting us for much longer than how long I believe the Heart that they discovered has been around, which leads me to believe that they have been and still are "Minions of the Darkness" / "Bringers of Death" even without the Heart, and that finding the Heart, while changing their motives, still didn't change that fact. This leads me to believe that the Heart, while still a major threat, isn't the Darkness incarnate, but something else.