My theory: the nine is a group of nine collapses, twilight gap, and future survivors, xûr, who was a survivor of the collapse and knows who the true enemy is, using coins to make a weapon to stop it, the exo stranger, read her guns desc, and you should get where she's from, the future, and is trying to stop the true threat to mankind from killing it, the queen, who is a survivor of the gap, and is trying to spy on the fallen to make them pay, ikora, a twilight gap, she is the brains behind stopping all the enemies and trying to build a weapon powerful enough, that it could destroy the darkness once and for all, Eris, we know what she survived, and what she's doing, lord salidon, gap, trying to make fallen pay for killing his brothers, finding worthy soldiers, rahool, he uses your legendaries and exotics for shooting down enemies that try to air strike us, the speaker, who may not speak what the traveler says, you might be a pawn, he could be the darkness, and finally you, you did and didn't survive the collapse and have no memory of what you did, but it feels important...