How much do members of the Imperium know about daemons?

[Sothalor]

Yeah, Cain admits to having called down an arty strike on a daemonhost in his private memoirs, something he composed after a decades-long association with an Inquisitor, during the course of which he was repeatedly dragged into situations far beyond the normal experiences of any guardsman.

 

As for knowledge of the warp and daemons specifically, well, I doubt even a fraction of a fraction of the Imperium taken as a whole understands anything about the mechanics of interstellar travel, much less the denizens of an alternate dimension who are embodiments of concepts and emotions and interact poorly with material reality.

 

That said, the fundamental catechism of the imperial creed appears to be "The Emperor protects," so there is definitely a widespread belief that there are enemies of humanity out there. Heck, the average citizen would probably conflate every xenotype and daemon, if they saw images, as a type of generalized "abominable other."

[Leif Bearclaw]

Yeah, Cain admits to having called down an arty strike on a daemonhost in his private memoirs, something he composed after a decades-long association with an Inquisitor, during the course of which he was repeatedly dragged into situations far beyond the normal experiences of any guardsman.

 

 

He also brings it up in a regimental briefing. They also had a showdown when a Gellar field malfunction led to a Daemon manifesting on the bridge of their troopship. The troopers and Priest involved all seemed relatively nonplussed by it (certainly no more so than what we see of the Regiment facing down xenos gribblies). Hell, in the Cain books, Necrons appear to be more mysterious and classified than Chaos or Daemons. Cain-Imperium seems to operate more on 'we don't go out of our way to teach you about it, but aren't going to waste resources killing valuable trained soldiers because they know Daemons exist'. Knowledge of the Traitor Legions and Chaos in general is certainly widespread enough for a healthy and thriving rumour mill around the 13th Black Crusade, despite Cain being on the other side of the Galaxy.