our story begins with a god-like being of immense power known only as the Emperor uniting the warring factions of Earth and embarking on the great crusade to reunite all of mankind's lost colonies he did this by creating 20 leaves is a post human genetically engineered badasses known as Space Marines each with an even more ridiculously LP Primarch to lead them unfortunately the four gods of chaos weren't really into that sort of thing intervened to discover the prime acts across the universe while still in their infancy rather annoyed by this the emperor led the legions across the galaxy reclaiming subjugating annihilating every world they could find gradually picking up the lost pry marks along the way eventually the Emperor decided there were more important things to do him retired from his career of galaxies plundering to go and muck about with ancient science back on earth leaving his favorite Primark Horus and commanded the crusade all was going well until the chaos tainted Chaplin Erebus engineered a plot in which horse would also fall to chaos already suffering from some pretty serious daddy issues Horus gathered half the space between legions suicide and said about waging civil war against the Emperor this conflict will be known as the Horus heresy and culminates in a massive invasion of earth the Emperor knowing is forcible out no midden on the verge of losing the battle teleport it's a horse's flagship to engage him in mortal combat but being a sentimental old sod could not bring himself to kill his favorite Sir Horace humming no such qualms beat the snot out of him finally seeing sense the Emperor killed with mined bullets and the loyalists were victorious near death the emperor has placed in a huge machine known as the golden throne which maintained his psychic essence at the bargain price of the souls of $1,000 he sods every single day the Imperium fell into a state of technological regression in brutal dictatorship for 10,000 years has been under siege from all sides by every single nasty the universe can throw at it basically life sucks there's only warming you probably gonna get eaten by tyranids have fun