If I understood it correctly then it was something like this:
Many many millennia ago there were basically only the Old Ones and... some other dudes... Necrons before they were robots I think?
And those two had a war going and the Old Ones created other races to serve them.
The wiki even mentions Slann!!?? But that is pretty old edition lore so it might not be true anymore.
Eldar we're supposed to be servants and Orks were basically a bioweapon that got out of control at some point.
Not sure about Tyranids I think those came from another Galaxy the way I read it...
A loooot of stuff to read through.
I'll just give you a recap of, The war in Heaven. 60 million years ago, the Old ones ruled the galaxy. The Old ones were masters of genetic engineering and psychic powers. The Old ones weren't alone in the universe, many other alien empires existed and the Old ones uplifted them to their technologi level and lived in harmony. It wasn't everybody who saw the Old ones as benevolent givers, no, a sinister and miserable people called, the Necrontyr were jealous of the Old ones. The Necrontyr were ignored by the Old ones, because the Old ones saw the hate and jealousi in the Necrontyr, so they chose to ignore them, hoping their misery would be the end of them.
When the Necrontyr had build a major empire, they declared war on the Old ones and all their vassal species. The war had major casualties on both sides, but it was evident that the Old ones were going to win. During this war, the Old ones created the Elder and the Krorks. the ancestors of the Orks. A Krork is basically an Ork that has human level intelligence and strategic thinking.
When all seemed lost for the Necrontyr, they noticed a being orbiting their home star, sucking the very energi from it. The Necrontyr contacted this being, and realised it was a being of unlimited energi. The greatest sceintist of the Necrontyr created their ultimate creation, a suit of living metal that the being could reside in. More of these beings came to the Necrontyr an had body's made to them. An so the C'tan were born. The C'tan has feasted on stars ever since the Big bang, but when the Necrontyr gave them material form, they realised that Souls tasted so much better. The C'tan were masters of the material universe, creating blackholes on a whim, ripping holes in reality and causing quasers to extinguish.
The C'tan promished that the Necrontyr could win the war, but at a price, which the Necrontyr gladly accepted, but quickly regretted it. The C'tan created titanic engines of matter-conversion, that striped the soul and flesh and turned a person into a machine that couldn't be destroyed, scared or beaten. So the Necrontyr had died and the Necrons were born, with the laughter of hungering gods echoing through the void.
So the war in heaven began...
With their newfound power, immortality and the help from beings that can manipulate the material realm to their wishes, the war quickly turned in the Necrons favor. The Old ones were on the Backfoot, they couldn't kill the Necrons anymore and many of their allies and creations were going extinct. But they still had one big advantage, their psychic powers. The Necrons, and C'tan were incredibly vulnerable too psychic powers, but this ended up being their doom.
Before the Warp became the Warp, it was "the realm of souls". A place were all souls ended up to spend eternity in bliss. During the war in heaven, the Realm was overloaded. So much death, hate and misery was raving the galaxy, and the realm couldn't handle that, it was corrupted beyond all repair. The Realm of souls was no longer a place for harmony and peace, but a twisted reflection of the galaxy that corrupts all it touches. When the Warp was born, the Old ones and Elder practically went extinct because the psychic backlash was so great. The war was almost over, and the Silent king, the High lord of the Necrontyr, saw the error of his way and realised that he had doomed his kind and the rest of the universe. he plotted in secret with his greatest generals and scientists to destroy the C'tan. When the war was over, the Necrons turned on the C'tan, unleashing their most potent weapons of destruction. The C'tan were shattered, but not before breaking the Necron empire in a thousand pieces.
With the galaxy a lifeless wasteland, the Silent king ordered the Necrons to a great slumber, to hopefully never wake again.
Damn, i went all in on this.
