How do you keep chaos a secret in 40k?
How do you explain why some worlds look like balls of fire? How do you explain the giant freakin warp rifts that are viewable from Terra? How do you explain how the eldar Empire fell, or why the dark eldar exist? Do they just let merchant ships wander around space and hope they don’t happen to wander to close to a daemonworld because it’s not like they know they’re dangerous? The warp? Does no one bother to wonder if anything lives in the realm they use for space travel? If a planet is invaded by chaos daemons/legions do you just execute the entire planet? How did they explain to the citizens of ultramar “yeah you all have to leave and when you come back half the planet will be destroyed”? Could chaos not win against the imperium by just releasing chaos iconography everywhere thereby forcing the imperium to kill off it’s workforce?