Two days earlier.
After the Chaos Gods decided to go all in, the Daemon Primarchs had already been dragged out of that abandoned timeline. It should have been a mighty river, but Hogg's appearance had cut it off, leaving it a dry hollow.
If Hogg had never appeared, the Imperium's fate would have been to become that decaying giant, limping along for ten thousand years.
Erebus, whom Hogg had sent to enjoy his retirement inside a star, would have gained power, manipulated and groomed the hapless Lorgar, and turned the little preacher into an even more fervent worshipper of power, until he firmly believed that the Emperor was an omnipotent god.
Horus, sent to put down the rebellion, would inevitably have been wounded by the dagger. His sons would have carried him to the temple fated to be his end, making him the first loyal Primarch to fall.
Perturabo would still have been the stubborn man who cried, "Steel Inside and Out," but ended up being steel in name only. He would have become the MVP of the Horus Heresy, rewarded with a General's Cannon strike from General Jonson.
The Phoenician would have wept blood. Ful, controlled by the Laer Blade, would have beheaded Senior Sister, then carried her lifeless head toward his final fall.
And Mortarion? He would have become the stinking can he hated most. He might even have lost his title as Legion Commander, becoming a First Company commander mocked for ten thousand years by the Mongolian top laner.
Horus, turned into a puff pastry, would have become a venomous traitor and led half the Primarchs in a shameful betrayal. He would have annihilated most of the loyalists' fighting strength at Isstvan III, becoming that tragic tale in Hogg's memories that he never told anyone.
Had events