Or, Killing troops because they saw a deamon.

What's the best way to go about it? Has anyone read a pertinant account in any material?

With regards to the specific campaign it is likely to occur amongst the forces in a retreating fleet.

Well,,,

in the VERY FIRST TableTop-Rules, it was mentioned that Imperial Guard units which fought and one against a Daemon ARMY where later lured into ambushes by other units who where to kill them (whom in turn where told that they were fighting "Traitors"). I think it was mentioned again in the last "Codex: Daemonhunters" for the TableTop.

While this is very 40k-grimdark, I am not so sure about killing troups for just seeing a daemon. Fighting a daemon army might be a different thing altogether. the Inquisition might get "first picks", some might be mind-wiped. But the rest might end up being killed for the moral threat their war stories would be . Sending in Sororitas for such a task would be an idea. They could bless and bury the dead as "martyrers" in the end

I seem to recall there being something about this in the book Daemonhunter. It says something about even the mighty Astartes are usually mind cleansed after certain daemonic encounters, particularly ones that also involve the grey knights. Although all this is very 40k grimdark, even this seems to me to be blatantly wasteful. There are much better uses of these troops, who, if they survived a battle with a daemon army must be tough. More likley they would be picked through by the inquisition for recruits but the remainder would probably be consoldated, segragated, and dumped into another meat grinder. Another daemon or chaos battleground or against tyranids are likley possibilities.

Although surviving troops may be 'tough', the potential devastation that they could cause far outweighs their 'usefulness'. Marines get mind-cleansing treatment as they are extremely valuable and rare assests. They are also consistently checked by the Librarium for any signs of taint after having been exposed to Chaos.

It is usually very rare indeed that more regular Guard escape being cleansed by the Grey Knights but it has happened (see: Cadians).

One of the stupidest old bits of fluff in 40K, and I wish they'd stop reinforcing it by bringing it up again and again, talking about it like it's the standard procedure for whenever there's chaos stuff around.

Sure, a full-on Daemonic incursion, where the stuff of the Warp is bleeding through in to reality and potentially taining everything that so much as breathes in its general direction...

But going by the fluff, the Imperium should have scoured Cadia clean of life at least 13 times by now, which just doesn't work because it should take more than one or two generations to rebuild the population and get them in the shape where they're producing crack IG regiments again.

Likewise in the middle of a grand crusade like the Sabbat's Worlds, or Jericho Reach, you can't just pull several hundred thousand men out of the line and have them executed just because there were some daemons running around and they might have SEEN one.

It's best to take the whole idea with a grain of salt, and just tailor its appearance in games to your personal tastes, and whatever the game calls for at that moment.

It varies with the Commisars and Inquisitors involved. It's also firmly in the "take from fluff that which works for you" category. As Blood Pact mentioned, Cadians fight chaos so often, there would be no cadians left if they purged every time a nurgling showed up. You could also explain it away as the reason why Cadians regiments seem to be involved in every conflict... they might be trusted to purge their own and as such, seen as demon fighters of a lower degree.

There was a Sabbat Crusade book done in a 8 x 11 format that discussed how one regiment in the crusade was purged. It was only after extended contact with demonic forces and, IIRC, at a point where physical corruption was starting to take hold. I think you could look at this particular approach as "We use them til they are annihilated or they're more trouble than they're worth, then purge them". Meanwhile, uncontaminated regiments are held back as much as possible.

I have a REALLY hard time with the idea that Astartes are mind wiped after demonic contact. It contradicts so much other fluff out there that it's not even funny (e.g the White Scars have a novel about them hunting a particular demon prince). I only look at it as a mind wipe after seeing the Grey Knights in action, not simple demonic contact. That is to protect the Grey Knight's advantage in case the Marines in question go rogue and spawn their own demon prince.

If Gaunt's Ghosts were executed whenever they saw a daemon, that series would have been pretty short...

I guess a lot of it depends of the perception of corruption. In CorpseGod's example, if there was physical corruption beginning then Puritan Inquisitors would purge first, ask question later. A 'less-puritan' Inquisitor might however recruit some first*, or even turn a blind eye so long as they kept fighting for the right side (some corruption is armour against the fear after all!).

*"No no my Lord, the company of IG veterans in question that had fought the whole campaign in the thickest fighting had succumed heavily to physical mutation and battle madness and were therefore declared traitorous-malefic and ordered purged as you instructed."

...

"Ah no, I cannot confirm an unknown IG company being loaded on to a privately chartered aircraft and deposited at the space port, absolutely not my Lord."

...

"Ah my Lord, my investigations have revealed that the aircraft was chartered by a front company belonging to one of your interests my Lord..."

...

"My Lord, I suspect we may have been infiltrat....acccCCCkkkkKK!!!!"

Well clearly it's up to the inquisition at the time.

In the fluff for the first battle of Armorgedden I'm sure it says they basically kill everyone involved, where as clearly that isn't the case on Cadia as a few Daemons in the place would be lost.

As you say maybe it is dependant on tested corruption, like if whole units are full of Nurgle plagues then you might need to get rid of them, or driven irrevocably mad by the influence of Tzeentch.

And I don't remember them ever doing during a battle (other than to put down spontaneous chaos spawn or something) so it sounds like they might as well try and get them killed in combat before having to finish them off.

Why would there be a specific need to kill troopers who've seen a daemon?

After all, those who've seen a daemon can be generally categorized into:

-Dead (killed by daemon, or executed for cowardice)

-Heroes (those who survived fighting the creature)

And the latter category tends to be quite small... and of interest to the inquisition. I think those who survived a match against a daemon would be of interest to the =][=, as proven capable of taking on the worst of enemies.

So, my take on this would be: Those who ran away -> get dealt with by the comissars, those who fought and survived -> get taken in by the ordos as agents / operatives / acolytes / quality cannonfodder.

H2SO4 said:

You forgot the third category:

-Hero Imposters who survived contact because they were infected by the thought seeds or made a pact with the deamon in question in order to infiltrate the Imperium and create an even larger incursion at a latter date Just As Planed by You Know Who...

H2SO4 said:

Cause they're not just talking about a platoon (or more realistically a company) of Guardsmen who've been seconded to the Inquisition for a mission.

Mainly it's talking about whole wide battlefields where daemons manifest and do battle against the loyal forces of the Imperium. The Guardsmen who survive those battlefields aren't heroes, for the most part they're just lucky. And their minds might have been so shattered, and souls so scorched, by the utterly tangible horror and power of what they're confronting that they're corrupted by it.

Puritan Inquisitorial stance: Better save than sorry. (After having picked the best for the =][= of cousre.) And PDF-Troops / Guardsmen literally grow on trees .. eh in Hiveworlds.

Its understandable that some puritan Inquisitors just clear the field. While more moderate ones might go through a strict weeding of the units for signs of and one not being 100% pure, perhaps even erasing 50% of the survivors. And/or ordering these surviving units always into the most dangerous missions so they are ground away by attrition (Dont be wasteful with HIS resources). And giving the rest of the units a higher Preacher and Commisar quota, while also never gining them sensitive missions any more.

But Always eradicate Everyone? - Nah.