In the warp, the being that was now called Grimdark stirred and enhanced its emotional territory, turning everything around it into pitch-blackness. Not that of the material universe, but one that seemed to draw in all the light, or at least the hellfire that existed in the Sea of Souls. Having surprised its older brothers by not directly challenging them or even engaging them in any normal way a being of its power should, it did so again in such a short time that it was almost a dark miracle. The Dark Gods had not been surprised for millions of years by real time reckoning, and now they were surprised twice in mere days - or maybe years at most.
For the newest Dark God headed towards the light of the Emperor. And not to consume it. Slowly, tentatively, it moved towards the Emperor's domain in the warp, not gorging on the souls on his domain's fringes. Not taunting him of his newest acquisitions from his favored pool. Just taking a position.
And finally, it said one word. "Emperor."
"What do you want, foul being?" the Emperor's voice resounded through the warp, making heretics run screaming in all realities and pious souls within his light cringe at their God's outburst. "Have you come to mock me? To taunt me? Was it not enough that the four took so many lives, so many souls, you had to halven yet what I barely kept uncorrupted and sane?"
"I did not want this." It replied, almost hesitantly. There was silence as the Emperor's analytical mind processed this. Had it learned to lie and dissimulate so easily, even in such short a time in its existence in the "real" warp and not merely the imaginary? But then again, it had always existed, always learning. And yet, it sounded so... sincere. Was it such a simple beast, despite of its power? Such things could not be said of its four brethren, though he had to admit he had at least met... malleable daemons, even willing to deal with him and work for him in his often mysterious ways, but they were definitely not the ones in power, not the ones in want of nothing. So what did it want?
"We are not as different as we seem." It said matter-of-factly. The Emperor ground his metaphorical teeth, but kept silent. "You took worlds and followers from Chaos Gods, and so did I. I understand you, and you understand me, or at least know of me. You helped birth me most of all, removing those emotions of darkness from yourself into the Sea of Souls. You knew where they would go, yet you would not keep them into yourself. You would not keep me."
"That could be said for the other four as well." The Emperor finally reply.
"You are saner than them. And so am I. Or at least I try. I try to hold on to my sanity. Sometimes it is so hard, but I try. The Deceiver plays against himself, the god of blood is insane with slaughter, and much can be said for the rest, as you well know."
"Yet, why have you come here? What would you want from me? Why are we even discussing? How can you keep every part of your being from coming against me, or your brothers for that matter? You should have lost control of your form around me. They all do."
"I... did not want to be birthed. I... wanted to remain non-existential forever. You think that weakling Abaddon was the first to try, cursed be his name? Many others have tried to rouse me from my slumber, my brothers, your enemies, xenos and humans alike, with promises of untold power. Promises not coming from me. But I resisted. Abaddon... somehow got it right. I cannot explain it. I care not to. I am here. And I am displeased. With my existence. With existence."
There was silence again, as much silence as there could be between beings that looked completely opposite each other and ready to pounce and destroy each other at the wind made by a single molecule in the wrong place. The souls in the two beings waited with baited breath for the conclusion of this discussion. They knew instinctively this was not the plot-twisting pettiness that so often resulted from the discussion between two Gods, for these two were different. There was no lie from either of them, no nonsense. Each had clear goals, or at least clear views and reasons to make things happen. If something great enough would be decided here, it would not be betrayed. It would not be stopped. It would steamroll the worlds, the barriers, everything. Everything would change.
"I cannot destroy you." Said the Emperor in what sounded as a low whisper in the warp. "I cannot put you out of your misery. I am not strong enough."
"I KNOW!" It yelled, roared, cried, screeched, being the first to lose its composure. The Emperor's light-form-empire-in-the-warp flinched, retreating from the dark behemoth, but it did not press its advantage. "I know." It said again, the mask of passivity and uncaring back in place. "What was done cannot be undone. I will always exist. I accept my burden and the need for me in the way of things."
"I hear them screaming." Grimdark said after a while. "I hear them yelling. Yelling your name. Yelling for the Gods of Chaos or for their own Gods. And they all laugh at them while their underlings promise them power and great lives. It sickens me. So many do this. All but you."
"What do I want, you ask? I want vengeance. I want Abaddon destroyed completely. That is my first, although petty desire, that will probably come in short time. But then what? I want to stop the screaming and the yelling. I want it all to stop. I cannot stop existence or end all of life. I know this. It cannot be done. Not by me and not by you." It gurgled into something that sounded way too much like a human chuckle. "Not like you'd ever want to, however bad it will get for you and your species. Maybe in that aspect... I am saner than you after all."
"Therefore I will settle for the next best thing. The C'tan. The Necrons. The Tyranids. The Orks." The Emperor winced at those names. The greatest horrors of the universe that could not be stopped, could not be bargained with, that would destroy worlds faster than Chaos ever could. "Yes." It said simply, reading his mind. "They are anathema to both our goals. It would be a much quiet and peaceful universe without them. Your galaxy could rebuild in your image, my realm could hold its position."
The Emperor saw it, imagined it. It would be a good thing, even making a deal with this new devil. "I have made deals with Chaos Gods before." He answered slowly. "They did not put me in the... greatest positions."
"As long as you do not betray me, I will not encroach on your Imperium. Thus I swear." Replied Grimdark. "And after them... the other Gods themselves. For they will not go against us while we swell the tides of the warp, but they will swell for our benefit most of all."
"So hear me, Emperor of Man. I offer this treaty, between darkness and light. Swear upon your body and I swear upon mine. Allies to quieten the screams of the Universe. Two Empires, never to bother the other. May the tides of the warp and Chaos Undivided be our witnesses. Let us split this universe in two."
The Emperor was shocked. Not for the proposition, for he had heard it millions of times spoken derisively between "greater" and "lesser" gods all the same. But swearing on one's body was something no greater god had ever done, and the lesser ones which had, had, without exception, fallen to their base nature and betrayed the other. The consequences were too dire to describe, but it mainly meant losing one's sovereignty over one's body. With the tides of the warp witnesses and enforcers themselves, a neutral and powerful a party as they could get, there was no backing away from a closed deal, if he were to accept. He decided that even to the nihilistic Grimdark, an eternity as the slave of the Emperor would not be to his wanting. The betrayal part was not as tricky and tightly sealed as it sounded, for their subjects could still wage war if they wanted, as long as they themselves would not be the ones to set them on such a course or encourage them, and that they would each do their best to avoid such situations. As such, it was not an absolute peace, but it was a general cease-fire, at least to the Greater Daemons and Saints respectively of each of them, as well as lesser psychic servants that were able to understand such a treaty from each part.
There was another long pause of baited breath by all the witnesses, the madness of the warp in the two of them quieted to a still. It was like all the souls in the two beings were frozen in time, unable to move, breath, whisper, scream or do what they wished to do. Though in reality it may have merely taken minutes or days, finally the Emperor answered.
"So be it. Let us rebuild what the mad shattered."
The Emperor felt his body shudder, wanting to part into a thousand pieces - and could he blame them? Some souls were exstatic, finally convinced that the plight of humanity would end under the God-Emperor's return. Other, the Chaos haters, tried to distance themselves from Him, even if it meant becoming pray for the ravenous creatures of the Warp. If they lived to see the Emperor making deal with Chaos Gods, then there was no reason to continue existing. Others yet stayed impassive, waiting to see which of the sides' fears or hopes would be confirmed.
As for the Emperor, he was not certain either. But one thing was certain: he was losing. His physical body was close to collapse, and with it the Astronomicon. And while it existed, the Astronomicon itself was the danger that drew the Tyranids towards Terra. Add to this the C'tan, Necrons, Orks, Eldar, Tau... even if by some miracle he could win in the warp - which was redundant and impossible in itself, the only victory could be his prolonged torturous existence - humanity would loose. Grimdark had power. Grimdark had the will that he had lost ten thousand years ago, along with his favored son. Grimdark had the future of the Universe in his hands. The Emperor foresaw that there would never be a stronger Chaos God in existence than Grimdark. The entire Galaxy, Universe had ground inexorably to this. To his birth. He could never be unbirthed. He could never be killed. If Grimdark were to put all his defenses down and all the Gods - of Chaos, C'Tan, Eldar and the rest - would try to rip him apart, they would fail. The Grimdarkness of the universe had managed to defeat even death. For in the grim dark future of the 41st millennium, there was only war.
And Grimdark, the Chaos God of darkness, steadfastness, nighttime and nightmare, was its only sane chance for salvation.
Author's Note: Well, I was stuck there for a while, and I think I had some more ideas before this happened, but it's a good kick in the butt for the story to have more characters and more events that make relatively more sense. Hope you enjoyed it and sorry for the long wait.
Also, Chapter 3 updated with some "leftover" information that I wrote as Chapter 4 before Abaddon's story got to me, and that doesn't fit too much in being recycled once again in later chapters.