If Destiny and Destiny 2 have one fatal flaw, it's absolutely the meandering, cyclical narrative that spends too much time trying to explain away game mechanics to really make sense. However, recent events in the game have made things a bit more sensible, if you follow an absolutely insane fan theory.
But sometimes, the craziest fan theories are the ones that make the most sense, and this one just might.
In a lengthy post on Reddit, Destiny 2 enthusiast BC1096 discusses the ramifications of several recent additions to the Destiny lore. In recent weeks, Bungie has used character dialgue by the Ahamkara and Hive to indicate that the game is, in fact, actually a game in its own universe. And now the Emissary of the Nine spits out a few new bits of dialogue in the fifth bounty line of Destiny 2: Invitations of the Nine, which makes it seem like the real protagonist of Destiny is not the player's character, but the player themselves.
According to BC1096:
But let's start to breakdown things we have in front of us, and what it could possibly mean:
The Emissary is not a correspondent between Guardians and The Nine, it is our correspondent with the game itself. As in, The Emissary is bridging the gap between you as a human real life player, and the mechanics of Destiny's universe. She knows we are real, she knows where it all stands in perspective.
There is quite literally no challenge this game (or any game for that matter) could ever present us that would ever beat us. You can wipe 2,000 times, and in the game you are still going to be alive. You will still win. You cannot lose.
Even if you were to literally delete your character, and uninstall the game, you have won. Why? Because you have insta deleted any and all possible foes this game could ever present you as both a guardian and player. You've won.
Even if a boss deleted your character upon killing you, you aren't dead. You can create an infinite amount of characters, and take on the same challenges an infinite amount of times.
You know all the different timelines Osiris' clone army goes to? Well, a large majority of those "alternate timelines" are just other players doing the same activities but in different ways. They are all happening at the same time, all different, and all relevant.
The Ahamkara, unlike the Nine currently, understand this. They want out, literally. The Ahamkara understands you are human, that they are in a game. Their main goal is to be "real" like you and I. When you step away from the game, the moment you even think of Wish Dragons and Ahamkara you are giving them what they want. You are applying them outside of the realm of the game. You are making them more "real" in a dimension outside of where they are constrained too. That is partially why Riven says she is a part of you now. You have met her, you've killed her, and your going to keep that experience for the rest of your life. In a mental way, she is a part of you. Which gives her power.
The Vex are simulating a simulation of a simulation. A game of a game of games.
The darkness could, in many ways, mean the literal end of the game. When we beat the main bad guy at the end of the franchise, at some point your going to turn the game off. The servers will turn off. Darkness has come, a new dark age begins. Which is funny, before Destiny was released the B.net community referred to the time between Reach and Destiny as the "Dark Age". Bungie had gone dark, and a very small rag tag of Bungie fanatics stayed on through till we saw the light. Before the game existed, the darkness had won. The game was then created, dark and light met at odds thus creating the world we now play, then light really entered the game when we all did. We are the embodiment of light. We give the game life, we are what keeps the lights on. The moment we all leave, dark again.
Or, perhaps, Destiny and its sequel were hastily thrown together campaigns that the dev teams are frantically trying to tie together in a way that makes sense, considering you tend to fight the same enemies over and over, and can, you know, revive yourself from a corpse.
Personally, we prefer BC1096's theory, if only for the novelty of it all.