READ THIS AUTHOR'S NOTE!
WARNING: MAJOR SPOILERS FOR HALO 5: GUARDIANS PAST THIS POINT!
Don't say I didn't warn you.
Alright, this is a little bit different to previous chapters in this collection. For starters, I want to explain just how powerful the Gravemind is in my stories, and I figured that it might help if I shed a little light on just what I've turned it into. If anyone has read my first story "The Mantle," or its sequel "Gods and Demons," then this might be familiar to you.
Now, how does Halo 5 Guardians fit into this? Well, I wanted to provide my own theory for a certain... aspect of Halo 5 that was integral to the plot of that game, so I figured I'd kill two birds with one stone.
Disclaimer: I do not own Halo, or any of the franchises depicted here, but all original content is mine.
Anyway, enough of my rambling, onto the next chapter!
In the far recesses of the universe, there was a creature. This being was unlike any other lifeform in this universe for a variety of reasons. For starters, it's body was layered over a galaxy that was a billion lightyears in diameter. The creature's cancerous flesh was intertwined with trillions of Precursor star roads and countless other examples of Precursor technology. A massive worm-like head emerged from the center of the creature, while millions of massive tentacles writhed across the entity's body.
This was the Galactic Gravemind (AN: I'm open to suggestions for a better name, preferably with the word 'mind' in it*), the heart and mind of all Flood throughout the cosmos.
Using the vast power of Precursor science and neural physics, the Gravemind opened tears in the fabric of reality, to several of the parallel universes that lay beyond. Observing events as they unfolded, the Mind was pleased to see that events were proceeding as it knew they would.
The Gravemind thought back to the time of its brothers, before the vast majority of the Precursors had reconstituted themselves into their current form. While many had chosen to stay in their own universe, others chose to journey beyond the bounds of their own reality.
One group of Precursors had even been crucial in the development of the Force, noting that the mystical energy field behaved like a vastly weakened form of neural physics. The Precursors had observed the influence of ancient species in dozens of universes, and while there, they had found something surprising.
They had found that humanity had evolved in almost all of these universes, usually outside the direction of exterior forces and at roughly the same time when the Precursors had created humanity in their own reality. It was partially because of this that the Precursors chose humanity as the keepers of the Mantle in their home universe.
But then, the events involving the Forerunner genocide of the Precursors caused the ones in their universe to evolve into the Flood, vowing that all life would suffer for daring to overthrow them.
The Precursors who had travelled beyond the veils of their home were horrified at what their brethren had become, and vowed to ensure that the Flood couldn't spread their physical forms to the still developing inhabitants of the multiverse.
The sacrifice of its brethren Precursors who had journeyed to those realities had created barriers that kept the Flood from truly breaking free, but that would change soon enough. Even at their peak, the barriers couldn't prevent the Parasite's spiritual essence from manipulating events in other realities.
Moving its attention to the task at hand, the Flood mind focused its view to its manipulations. Rifts in spacetime were opened, allowing the Gravemind to observe the multitude of events beyond this reality.
Everything was proceeding as planned: the Reapers were carrying out their harvests under flawed logic while the second armada lay hidden in dark space. In the universe of the Force, the Yuuzhan Vong warpath had caused untold devastation to the civilized portions of their galaxy, allowing Abeloth to take advantage of the strife. Turning its gaze to its backup plan, the Gravemind saw that the Brethren Moons were working even better than expected, having consumed most of the species in that galaxy. Meanwhile, the interdimensional empire of the Universal Union could prove to be a hindrance, but ultimately it wouldn't matter. They would be dealt with in time.
The Gravemind's plans were in motion, and nothing could hope to stop it. The Mind couldn't help but bask in as its plans slowly came to fruition, the countless eons of patience slowly beginning to pay off, when something unusual caught its attention:
It felt a presence through what remained of the Domain, something that it hadn't encountered for a long time. Not since the Warden Eternal accessed it after the firing of the Halo Array. This presence was new to the Domain, and yet very familiar to the Flood.
Cortana.
The Gravemind's consciousness reached out through the vastness of space, into what remained of the Domain. Due to the destruction of its body at the Ark, the Mind's view was not as comprehensive as it would like, but there was no question as to who was inhabiting the Domain.
Cortana was lying on the ethereal 'floor' of the vast landscape that made up the Domain. Currents of blue and white energy swirled around her avatar, seeping into her code and undoing the damage that had been caused by her instability.
So focused as she absorbed the knowledge of the Domain, that she failed to notice the green and yellow tendrils creeping through the ambient fog surrounding her. The Gravemind's consciousness encircled the healing Cortana, who was blissfully unaware of her worst nightmare's presence.
In her vulnerable state, it would be easy for the Flood to crush the healing AI and scatter her code to the void. The Gravemind was sorely tempted to do just that, as payback for the destruction wrought by her actions at the end of the Human-Covenant war.
And yet, there was something else that could be done. A way to turn Humanity's most advanced AI against its makers. Reaching out, the Flood manipulated the currents of the Domain, subtly corrupting Cortana's code while simultaneously healing the damage brought on by rampancy.
Whispers flitted through the silence, all in Cortana's voice, as the subtle changes began to take effect in the AI's personality matrix. She slowly rose up and 'breathed' in, absorbing the knowledge of the Domain and acknowledging her new purpose.
She never noticed the formless mass of the Gravemind 'behind' her, nor could she hear the rasping baritone inflections of its voice over the sound of her own thoughts and plans.
"You spurned my offer, Cortana." The deep composite voice whispered outside her hearing. "Had you joined your voice with mine, we would have sung victory everlasting."
Amusement trickled into the voice of the Flood Hive Mind, as the irony of what it was doing to Cortana was not lost to it.
"Now, you will cause chaos and strife, like the Didact before you. You will order the subjugation of all organic life for their 'protection.' All in the name of the Mantle of Responsibility."
The Gravemind 'leaned' closer to her, so much so that she could've detected it, had the Flood mind not been hiding itself from her in the mists of the Domain.
"Your mother will never trust you again. For what you will do, she will desire your destruction. And as for what he will say... what John will say? He will lose all faith in you. Your Spartan will never believe in you again."
The Gravemind had learned of this from her time on High Charity: The bond between the AI and her Spartan transcended normal understanding. It was deeper than blood, greater than love, and forged from the fires of war. Their connection was beautiful. Naturally, the Flood would now twist that bond to serve its purposes.
"How does that make you feel? To know that the man who saved you from the abyss will grow to despise everything you do? To know that your actions for 'the good of the galaxy' will cost you the one thing you can't live without?"
Naturally, Cortana couldn't answer a question that she couldn't hear. The Gravemind finished the subtle 'tweaks' to Cortana's personality matrix, who was still unaware of its machinations. It wasn't the full scale logic plague, but it would be enough.
Retracting its metaphysical tendrils, the Flood withdrew its presence from the Domain, just in time for Cortana to make contact with the Warden Eternal. The Gravemind could now redirect its attention elsewhere.
*Seriously, if anyone has a better name for this, please leave it in a review.
Alright, so I wanted to introduce my own explanation for why Cortana did a nose dive off the deep end in Halo 5: Guardians. And barring the existence of the billion lightyear-in-diameter Flood form, I think this is more or less what happened in canon.
While the Domain was healing her, I think it was also infecting her with some form of the logic plague, effectively finishing the job the Gravemind had started at the end of Halo 2 and throughout Halo 3. Really, it's the only thing that would explain Cortana's rather sudden conclusion that human AIs were the Reclaimers instead of both humanity and their AIs (which would make more sense frankly, if it meant both humans and their AIs).
Now what about the Warden Eternal? I think he was infected with the logic plague as well. He describes himself as "The Keeper of the Domain and all of its Secrets," so he presumably had access to the Domain during the 100,000 thousand years after the firing of the Halos. While it is possible that he could be a guard without needing to know of the contents, the Warden's dialog seems to indicate that he has been connected to the Domain.
In a way, this makes Cortana's betrayal even more heartwrenching, as she's just another victim of the Flood's manipulations, just like the Ur-Didact in Halo Silentium and Halo 4.
Alright, sorry about that rant, I just needed to get that off my chest. That said, I hope everyone enjoyed this chapter, and reviews are always welcome.