I just had an interesting "after-action" debate with one of my players.

The party for my campaign is a group of "special ops enforcers" not (yet) actual Inquisitorial acolytes. They are starting to uncover evidence of a Chaos cult (suicide bombers with eight-pointed star tattoos) but, we all agreed, none of them actually recognize the symbol or know anything specific about what is behind it.

Afterward, one of my players, who is well versed in the 40K universe, wondered how much his character (an underhive ganger) would know once the connection between the eight-pointed star and Chaos was revealed. I suggested that his character would know next to nothing about the Ruinous Powers, beyond vague superstitions and religious dogma. We had a jolly debate about it, citing difference in various eras for fluff ranging from the ol' days when entire Guard regiments who fought against the Ruinous Powers were slaughtered even in victory to hide the knowledge of Chaos, to the more recent fluff with Gaunts Ghosts liberating worlds from the Arch-Enemy and bringing them back into the Imperium.

I found myself wondering how other Dark Heresy GMs handle this... how much do you thing the "common man" of the Imperium knows about Chaos, or Xenos for that matter? Is it a secret known only to the ruling elite, a half-known mystery obscured by supersition and dogma or do you have inspirational posters of Commissar Cain standing on the corpse of a Keeper of Secrets every young boys wall?

Well that is the joy of the 40Kverse- its so vast that with a million worlds, all interpretations are true.

Certainly in places like the Cadian Gate, entire planet will be well-aware of the 8 pointed star of Chaos as the mark of the archenemy that regularly assails them- perhaps even with names or synomens to distinguish the various Chaos Gods forces. But in primitive and isolated feudal worlds where the Horus Heresy is mere myth and allegory of angels warring in Heaven then they might be completely ignorant of any particular chaos symbolism whilst the preacher still entreats them to shun 'Ruinious Powers' without specifying how to recognise them other than they'll make your eyes water and sicken the core of any tru faithful.

So yes, you can argue anything in the 40kverse. Ultimately its a GM call on how much general knowledge: Chaos the population have access to.

SJE

Yeah, of all the things in the 40Kverse, that's the one that most depends on the writer. It seems the generalised, superstitious knowledge is the most consistent but any contact with actual chaos and its iconography (if it could be identified as such) would result in your team being exterminated (the investigation passed up to the higher ups who have proven they can handle such things), mind-wiped if their combat skills were useful enough to be worth retaining, or they'd be carefully watched by an Inquisitorial representative to see if they have potential (and to exterminate them etc if they fluff it). I think some of the IH Background Packages show this (eg the last line of the Arbitrator Calixian Pattern Killings and some of the Guard ones).

But specifically, since icons have power, I'd guess that the public and low ranking troops etc would no way know what the eight-pointed star symbolised (exceptions like Cadia mentioned above notwithstanding - given their strategic importance). Once you do know what that star represents, you'd best be pretty strong willed and obviously useful to the Imperium!

I've treated the 8 pointed wheel of chaos much like the pentagram. Virtually every Imperial citizen knows that it is an occult symbol, and most would know it is connected to the Ruinous Powers and/or the traitors of the Horus Heresy. But few would have more detail than that.

I like to use the Imperial Infantrymans Uplifting Primer as a gauge for some sanctioned common knowledge. Even in that though it just makes vague references to "Dark Forces". I'd imagine unless you've served in the Imperial Guard during a campaign against chaos, been an Arbitrator or a citizen who's planet has been attacked by chaos then you won't know anything beyond superstition like the guys have said.

As for Xenos I think that's more widely known but still fairly basic facts. My players are working for the Ordo Xenos so I actually made a new Skill called Common Lore Xenos using the IGUP as a basis for comedy knowledge like: "ah yes I know about that Xenos, it says here in my little book that Genestealers are a slow and sluggish target with puny claws and stumpy legs. They also quite often attack each other when panicked. I'll grab my lasgun at sort em out your guys stay here and relax..."

Generally I believe the common citizen thinks the brave Imperial Guard are out shooting puny bugs and conquering new worlds for the Imperium and not fighting for their lives barely holding off the ever encroaching hordes of Xenos attacking Imperial worlds.

Attila-IV said:

I go even one step further than that in some areas of the galaxy, to the point quite a lot of imperial citizens think that xenos lovers and chaos cultists are practically anyone else not in your particular suburb or village and strangers are more than likely a witch because they're not at home or working somewhere sensible so they're up to no good- are probable cause reasons for the local wannabe witch hunter organising a mob, grabbing some pitchforks and killing the offender with fire. Like most forms of home-grown zealotry and ignorance, the 'witch' gets rolled for all their worldly chattels and that goes back to the church for re-distribution to the needy.

On the upside though, gib a few of them with a boltgun into red smears and they'll think you're the 2nd coming (or at least piss off to bother someone else)

An underhiver ganger would be hell bent on scrapping together a pair of hard earned coin at a pub than flipping though holy texts to study the taints of Chaos, so to the orginal poster's player I would say his attempt at rationalizing why a ganger would have any chaos knowledge is rather mute when most if not all gangers are intrested in the bottom line of profits over religous matters. Now if he was a Cleric or even a Tech-Priest, that would a different matter. Player knowledge of a matter does not relate to in-game knowledge for the player's character as that character is neither trained or aware of such matters if he doesn't have the propper lore training.

As for the Chaos gods and their respective avatars/servants, the 8-pointed star may not always be used. The Word Bearers are one of the few direct cults to represent the 8-pointed star of chaos to express their devotion to the ruinous powers, if memory serves right. But each god has its own markings on its servants that are not uniformed, either etched into the flesh or soul pending the god in question and purpose of the follower.