The Nine are the Afterlife, the complete master record of everything that has ever existed.

"Now drink, and as you die and are reborn, I will reveal to you the destiny she has realized for you, the right and singular fate to which all your principles and purposes will bring you."

To drink the poison, continue reading.

It tastes of bitter regret and psychosis sweat: a poison to end the thoughts of Human, neohuman, or machine. You see the cosmos before you like a spiderweb of light. Filaments of galactic supercluster shine in the clouds of invisible dark matter, which glue their mass together. Dark energy yawns in the space between all things, ever-growing, ever-spreading.

Life arises. Life spreads, contests itself, and changes. Great things are built and destroyed, but from your vantage point, you see that the victor of each struggle contains—in its negative, in the marks left upon it by the loser and the shapes it assumed to win—the master record of all that it has beaten. Information may not be erased. Whatsoever survives until the end of the cosmos will possess and remember all which came before it.

Now, compare this to what Lavinia from the Dust lore book experienced,

With a horror of revelation so absolute that it would drive her mad if she still had sanity to lose, Lavinia understands where the Nine have always been. They are within everyone, every system, every living and moving thing. Trillions and pentillions of slim dark matter tentacles plunged through all our bodies, drinking up the complexity of our lives and thoughts.

We are all pinched silhouettes impaled on the twitchings of infinitely long spiderlegs.

Now, why is this important? Well, in physics, there's something called supersymmetry. Supersymmetry suggests something very peculiar with its existence,

Many elaborations upon and theories beyond the Standard Model, including the popular supersymmetry, double the number of elementary particles by hypothesizing that each known particle associates with a "shadow" partner far more massive, although all such superpartners remain undiscovered.

I mean, the Nine say it themselves,

WE ARE THE SHADOWS OF YOUR WORLDS' MASS

Too large - to see
too small + to miss

Now, what evidence is there that the Nine actually have a record of everything that has existed? Well, there's Lavinia. She discovered that two different factions of the Nine are trying to find ways to gain bodies, independence from the need of life to exist (KIND OF CURIOUS WHAT CLOVIS WAS TRYING TO DO NOW EH? LOOKING FOR A WAY TO TRANSFER CONSCIOUSNESS INTO IMMORTAL BODIES?)

No. Of course she is not safe. Because there are factions among the Nine: one faction sent Xûr and Orin to study Guardians and the Light, to seek the secret of effect-without-cause and to protect the source of that secret, the last source, now that the Ahamkara are gone. Those five played at alchemy with the Cocytus gates, turning dark dust into energy and then into matter, but they could not unlock the secrets of our mad existence. They needed ambassadors. Go-betweens.

The other faction walks a different path. A path of folds and needles slipped through spacetime itself, existential syringes yielding new spaces, to be remade as the Nine desire. They have tried to gather enough dark dust in one place to form a black hole, and found it difficult: when the dark mass collapses in gravity's fist, the dust passes through itself and scatters.

"Someplace where you're appreciated. Where we can really use everything you've learned." The old lady pours a thin stream of tea into a cup of bone. "Didn't I tell you that you were lucky, back when you were born?"

NOW HOLD ON. I know what you're thinking. How do we know if this proves it?

Well, there's only one other assumption we can guess. Savathun traveled through time to arrive at Lavinias birth and disguised herself to plant the seed of connection so Savathun can better manipulate her, but...

Now, why is this important? Because of Eris. Back in Forsaken, we got Truth to Power, in which multiple narrators talk slick with us and tell us a lot of nonsense. But the curious part is what Eris tells us about her past life. She goes into great detail and explains a lot of things about her Golden Age life, and it sounds believable, especially when we consider what Eris became in the Dark Future, and now with Lavinia being used.

But why should we still be wary of Eris? Because that great grand plan Mara has, the one that involves The Stranger and the Drifter, the one to decide our fate? Eris knows more about it than anyone else.

The plan exists in her mind alone, although beloved Eris has by necessity learned most of it. The Techeuns do not know the whole plan, although they will position the Harbingers upon the threshold. Even sweet capable Petra does not know the whole plan.

Now, the Nine are a complete master record of everything that has ever existed, they are centered around our solar system, and one of the factions is working with Savathun. We have Savathun who stole Lavinia who learned about most of Maras interactions with the Nine,

In passing, Lavinia sees the entire history of the Queen's interactions with the Nine: more than anyone suspected, and more vital.

So Savathun could've learned about Eris role in her plan from what she took from Lavinia. Now we move to Clovis Bray, who interacted with the Darkness. Or is it actually the Darkness? Look at what he says after he has the vision by Clarity Control.

Clearly a message from Clarity Control! And written in allegorical large print. I am, in the eyes (or whatever percepts it possesses) of Clarity, the leader of humanity. This is why they contacted me. This is why they want me.

They are an association of coordinators, those whose choices cause change. And they are inviting me into their pantheon.

This doesn't sound like the Darkness does it? It sounds a LOT more like another faction that Mara encountered.

There came a morning when the Techeuns spoke in unison, though none were near each other, and they said, ++WHO ARE YOU WHO BUILDS A HIDDEN CITY HERE IN OUR THOUGHTS?++

And Mara, alone in the Queenswalk of the Dreaming City, heard their voices ring out as if each Witch stood beside her, and she said to the empty air, "I am Mara Sov. Who are you?"

The answer came at once, ++WRONG! IT IS THE EKPYROSIC. WE ARE THE NOTHING-SPACE FABRIC.++

Hearing this, Mara recognized a riddle. She turned at once and left the Queenswalk so that Riven would not be inspired. As she walked, she thought. At length she said, "Wrong. You are the Ancients. You are the idea that gives fate its shape."

That one-voice came again, as clear and strong as the birth of the universe, booming with dispassionate curiosity, ++IT THINKS ITSELF WISE! HOW DID SOMETHING LIKE IT ATTAIN SUCH REVELATION?++

Nothing-Space Fabric? The Ancients? Association of coordinators whose choices cause change? WHO ARE THESE PEOPLE?? Well, what if we already have their identities? But I digress. I could be wrong. Who knows?