Destiny has a complex short story that was built to raise many questions to make this a deep story. Now my theory suggests that you are a commander of some sort and you have some REAL impact on how the light works in the future. Here are a few bullet points I wanna throw out there. 1. The vex as we know can warp through space and time in an instant, we know that if that happens that time is frozen, and there for the vex time travel. 2. In the beginning of the game your ghost is looking for someone in particular and ressurects YOU and saids' "There you are, you've been dead for a long time..."This suggests the the ghost was looking for you and only you for whatever reason may be unclear. 3. When in the library on Venus, the mysterious female exo is there with you she tells you about a "Black garden" which as we know has significance. But notice how she saids' "Yes there here, with me now"..."Kill the engine, stay put, and don't let them find you." which suggests that who ever she is talking to is in fact a valuable target if the unknown enemy is searching for him/her. I believe that this is you, You sent your companion/ sidekick to assure your mission is a success, which explains her mysterious attitude and intelligence on everything, "I was not forged in the light" maybe she was rescued, someone like that would only be rescued by you, statistically how games work. 4. Now say you are a general of some sort, your a target and your being hunted, your at war. This war could be against the darkness a new foe, or as other conspiracys go, The Guardians fall under the darkness, which is very hard to believe but well go with it for now. If that is the case then you discover this with not much time, I would conclude that your become an rebellious force against the true darkness, and or maybe a civil war and you are the guardian that must eliminate the darkness and give the universe back its light. Based on Bungies' history in halo the elites underwent a civil war with their covenant and joined the UNSC, We sort of see the same thing happening in Destiny where the fallen are aiding the queen and you are helping her out, "I have shown you benevolence" The queen is a difficult character for me to understand right now but She is indeed powerful, she intercepted wars and turns many tides, shes the link between the guardian and the fallen. In conclusion this game will be very long and very deep, and we may not know for sure exactly what happen until confirmed but I say this is a pretty interesting theory.