At some point I'm pretty sure they're being vague for the sake of vagueness. I've always viewed the Darkness as the Elder Scrolls would view a Daedric Prince (mostly). Something that is a literal entity but is also a philosophical enigma. For instance, Mehrunes Dagon is a literal daedric prince, but he exists as the embodiment of ambition. Molag Bol is another literal Daedric Prince, a being and a body, yet at the same time being the embodiment of Domination. The thing about the Daedra is that, since they are embodiments of intangible things, they are in fact immortal. Can they be killed? Yes. But are they dead? No. You can't kill ambition, or domination. Stave it off, have periods of peace, but it's always around. Such is why the deadra influence fluxes and wanes with the tides of mortal events, feeding off their realm of existence and which is most prevalent in the world at that moment. (This is a very loose and probably shady explanation, but it kind of portrays what I'm thinking.) The Darkness is sort of the same thing, but on an all encompasing level. I view Darkness as the embodiment of entropy, and the light as the embodiment of structure and stability. All things lead to entropy, as the Darkness affects all things, yet structure and order is a part of the universe. Entropy seeks to undo order, yet order always remains in small ways. Geological formations, gravity, universal constants. Stuff like that. We see this as the Darkness is often viewed as 'magic', defying the laws of order. It warps the minds and bodies of those it touches, while the Light enhances and heals. The Dark lives by dying and feeding conflict, the Light lives by stenghening and protecting and nuturing. Of course, the Traveler is also 'magical' by introducing new laws of order. But, regardless, they still eventually are learned to be constants, Light works in particular ways, and it can be learned like any natural physical law. Different, seemingling random, but time has proved that laws exist. But, just as the Light has its entity as the Traveler, I think the Darkness is also a real, living entity. Not in the form of an army, or a faction, but in the form of a large and unfathomable will. The Cabal, Fallen, Hive, Vex, all of these factions aren't 'of the darkness'. They are 'minions' of the darkness. That's very telling. They aren't darkness, but pawns of darkness. If you're a minion... you might not even know it. Such is the way of the pawns. I'm not sure if Bungie really grasps this ideology very well. I think they're starting to make the Darkness a 'bad guy/faction' rather than a 'twisted, entity driven reality'. A reality that must exist because Light exists. If light exists, dark then exists. How do you fight entropy? I don't think they know how guardians would do that. Actually... it's why I've always thought the Vex made the most sense. Since they want to control all things, and thus, live forever they are actually fighting against entropy, against uncertainity. Yet, if they're so strong, why don't they understand the darkness? Well... I think it's because they can't understand entropy. Or... rather... they can't coexist with it. They know entropy is to risk, and to risk is to die. The vex want to live forever, and as such, will eventually seek to destroy light and dark. We, surprisingly, actually see this in the CoO (the ONE thing that was actually telling) because it is a place without light or dark. Without entropy. The Vex win, and both the light and dark die. Why? Because the Vex don't need it. Which, of course, makes sense why the Darkness so adamently goes after the Vex (in its own way) with the Hive. The Hive NEED the darkness, that's their way of live. The strongest live on the edge of the sharpest sword, the edge of pure entropy. When everything dies, only one thing is certain, and that certainity is that you're still alive. So it makes sense why the Vex and Hive are famously at war a lot. Both want the polar opposite, and one supports the dark while the other is against it. -- But, that's way off topic. The point is that I think rooting the darkness into a 'enemy faction' would be a terrible idea. But they don't have any other idea that results in a 'win' for the Light. The story would be too long, too dark, and too complicated to be told in the way Bungie is telling the story. Sadly, that's going to reduce the darkness inevitably from what it once was.