I have a theory about time travel in the story. At one point, if you read one of the in-game items or from the Grimiore (I think it is in both, can't remember) there is a log of two scientists from the Ishtar Collective long ago around the time of the Golden Age studying a Vex that they captured and severed from the network it's usually connected to. They find out that basically the Vex are us but Ghost says in the present when he studies the Cyclops' mind that the biological material doesn't match any known DNA sequence or some such. My theory is that we go one step farther than creating Exos at one point and a group of humans or Awoken in the far, far future where we survived the Darkness and evolved into something else turn themselves into cyborgs and work with each other by connecting each mind and creating one mind that stretches across time and space. This could also be the product of fighting the Darkness and needing more efficient coordinating efforts. Three people standing around a table and some old guy in a mask aren't the most efficient organization compared to one where everyone shares one mind. However, the Darkness is cunning and possibly lured us into a feeling of security after defeating it OR in the process of trying to defeat it, this group of people who became the Vex were corrupted by the Darkness and then used against us. Obviously they have mastered time travel since they are all over our system dating back to before humans or life existed in the Solar System, they have the Black Garden, which is outside Space and Time itself (possibly a pocket dimension), and of course the Vault of Glass. The reason, of course, is because we went into the Vault of Glass and, possibly after defeating Atheon, studied how the Vex were doing their time travel gig, therefore creating a causality loop. In the future, a group of After Humans become the Vex and are enslaved by a piece of the Darkness and then run wild across Space and Time. We defeat the portion of them that controls their comings and goings through time and space, therefore halting the Vex at some unspecified time in the deep future, the deep past, and then also the Present. They probably have backups of something like the Vault of Glass in other systems, so Vex messing around with time probably won't ever stop since before the Heart is destroyed, it's capable of controlling them across Time and Space OR the Heart is just one aspect of the Darkness among countless others we will face or that we may never face . On the other hand, the Vex we are fighting throughout the game's story could be alerted by the Vex in our future of our imminent interference and so are tasked with stopping our Guardian (or THE Guaradians.) or it could just be some combination thereof. There is, of course, the Stranger, who seems to use Time and Space like the Vex. I believe she comes from the not-too-distant future to make sure the Black Garden is defeated, therefore allowing us to go to the Vault of Glass, therefore allowing us to learn to manipulate space and time like the Vex do, therefore allowing her to do her appearing and disappearing acts. She watches you to make sure you're the one that's going to mess up the Garden, since the story is centered around your character being the pivotal historical figure that destroys the Heart. She warns you that it will not be easy and to be prepared, which is good advice, and tells you a few things about herself and also leaves verbal breadcrumbs to follow towards your "Destiny". She does this to earn your trust and respect, otherwise you would not listen to her, since she is not Forged in the Light and that complicates things for her (possibly in the future, new Exos are created that are not Guardians, bolstering the forces of the Light). There are also things she wishes she could explain but she: A) Doesn't have time, as she says, which makes no sense since she could take however long it takes to explain unless, since their time travel is probably primitive compared to the Vex, her present runs concurrently as long as she is in the past and that's because it's her anchor so she can return to it. B) Can't reveal who she is or where she's from yet since that would mess up the past. She's in the middle of a call and possibly also in the middle of a large battle in the future. At the end of what is the first chapter of your story as a Guardian, she rewards you with an assault rifle, which Ghost says has been exposed to immense forces and made of things that shouldn't even exist yet AKA it's from the future. Perhaps from just one possible future or a future negated by the Stranger going back in time, sort of like how Skynet sends the Terminators back in time repeatedly to kill John Connor and therefore negate the resistance in one possible future or skynet's present. What happens next depends, in the story as the author, on whether you believe time is immutable and if it's changed, the future is the same universe AKA Back To The Future, or in a multiverse where changing something in the past makes the past branch off into another separate universe and your universe you came from is relegated to just another parallel universe entirely AKA Futurama multiple times. Even the Future War Cult ties into this. Their origin is mysterious and dates back to the Golden Age but Lakshmi-2 is obviously withholding secrets. I believe she is sent to the past as well, to recruit for this future war. Both she, and the Stranger, have different missions but their goal is the same. There is a huge war coming and they need to recruit as many followers as possible and ensure that your Guardian destroys the Black Garden allowing access to the Vault of Glass, therefore making their future possible but it is also tied back to our past in the Golden age and our present, when the Guardians are pushing back the Darkness in what would be considered an important part of history. As others have, when they theorize about the story, I'll get the skeptics who will say I'm just justifying Destiny's "terrible" story. Sure, I could be, or this could all also be true and part of the new story Bungie had to create or the old story that was intended to happen penned by the guy who left. I'm perfectly willing to admit I'm trying to make sense of a cobbled together, messed-up story thrown together and just trying to piece together a pattern that doesn't exist ( we are rigged instinctively to put together patterns, after all) and that I'm just making up Epileptic Trees and Wild Mass Guessing. I hope others with a more open mind and less cynicism will think about this and reflect on what it is Bungie is possibly foreshadowing. Even an author can be unaware of what their storytelling implies or how it could be interpreted but they could also be setting up Chekov's Guns everywhere and we might be unaware. I realize I am possibly not the only person to come up with this theory. I don't have time to sift through the forums nor the patience involved but if you read this long, then I appreciate it. If I wasn't the first, I hope I have at least added to it or made it more detailed. [b]TLDR[/b]: Vex are biologicals we evolved into and then we became cyborgs in the deep future. The Vex themselves are a causality paradox loop since their use of time travel is directly from our study of their Vault of Glass. The Stranger and Lakshmi-2 are from the future and have different missions. The Stranger's is to guide you toward your destiny as the destroyer of the Dark Heart of the Black Garden, therefore allowing the study of the Vault of Glass where Atheon is defeated. Lakshmi-2's is to recruit for the war-to-come and she has survived and worked toward this goal as far back as the Golden age. Both are probably not forged in the Light and are Exos that were never killed by the battles with the Darkness or we began reforging new Exos to bolster our forces in the battles to come. Yeah, I know this seems like I am reaching but Occam's Razor cannot be applied to fiction since fiction is made up of planned-out circumstances whereas our universe where we use it is random and Occam's Razor makes more sense. I also know it looks like I'm trying to make sense of a story thrown together after the lead writer left but I personally believe that is not true. You are free to believe whatever you want, of course.