It's probably supposed to be Julienne, with the extra letters discarded. "C[a]iaphas" and "Bro[c]klaw" probably follow the same kind of logic.
But if you discard those letters, you get the Masculine form of the name (Julien is the French version of Julian).
It's the year 40,000 and there have been a couple of apocalypses along the way. Some language drift over names is to be expected. Hell, there are names that have switched between masculine, feminine, and unisex drastically over even the last century.
How is Jurgen Pronounced?
I've always thought it as being pronounced "Yergen" like the common German name Jürgen, in keeping with the sort of pseudo-German theme naming of the Guard. But I'm wondering why, if this is so, there's nothing to notify the average reader, who wouldn't pick up on it, of this. Is there an official pronunciation that will hold me off until Dead in the Water?
I've always pronounced it "Jergen", mainly because it seems that, given his lack of hygiene, naming him as a reference to a brand of soap (Jergens) would be the kind of ironic Stealth Pun that Sandy Mitchell would make.
The "Dead In The Water" audio drama uses the German "Yergen" pronouncation, so I think that we can consider that the proper way to say it. Of course, the spelling naming him like the soap brand probably is a pun as well, though purely a written rather than spoken one.
The lack of information about Cain's childhood is suspicious in its absence. The fact that he was educated in the Schola Progenium suggests that he was the child of Imperial servants, either military officers or someone in an official civil position, and records of them should exist somewhere just to allow him entry. Unless there was some special circumstances that got him in, but even that should have a record noting why. Further, when he was admitted to the Schola, his file should at least indicate where he was picked up, and by whom. He may have been recruited away from his hive of origin, but given the mobility oppertunities for someone, especially a child, born into the lower to mid levels of a hive city, it is unlikely he could have gotten far. It is also possible that what records do exist were sealed or removed by order of the Inqusition, but if they were to do that they would at least put falsified files in their place, as Cain's large public profile would only draw more attention to the missing documentation. Given the Right Hand Versus Left Hand operation of the Inquisition, Cain's association with Inqusitor Vail, and the fact that she is publishing Cain's memiors (for distribution only within the Inqusition,) it seems likely that some other Inqusitor would get curious enough to start digging, and finding nothing at all would set off more alarms than finding something bland.
The Imperium has been known to forget about entire planets due to rounding errors. This is no big deal. That being said, I have a theory of how the son of two cowardly troopers could become a commissar (assuming Cain wasn't lying about their status): Cain's luck is inherited. In other words, his parents were trying to run from something, got killed, and looked like they died heroically for the Emperor.
Uh, I know that this is a Crapsack World, nobody understands technology at all, and this is minor nitpick, but Cain takes it as AMAZING when the Tau have like, night vision and thermal sights on their vehicles. 40 centuries into the interstellar future?
Cain's adventures happen mostly out on the Eastern Fringe, which is sort of the ass-end of the galaxy and is much less developed or densely settled. With less infrastructure, the night vision gear you might see Stormtroopers or elite light infantry getting issued elsewhere are nonexistent.
Tau blacklight tech is something distinctly different from thermal sensors. Imperial Guard units do have thermal sensors (referred to as "heat-see").
You also have to keep in mind the wide gulf in technology and beliefs about technology between the Imperium and other races. To the Imperium, anything more hi-tech than the stuff they have now is heretical "technosorcery" since they don't understand the science behind it, whereas it's just equipment to the other races.
I think that they do have such devices, the Imperium is just very... particular about them. In a lot of the cases with the Tau's technology, what the Adeptus Mechanicus (and anyone educated about technology from them) is horrified by is less that the Tau's technology is advanced, and more that it is so advanced without showing the proper obsequious to the Omnissiah in its construction. They tend to think of their own devices as operating on a kind of animism, believing that it has a soul and is allowing its user to make use of it, while Tau constructs are soulless constructs. The idea that a construct could take the place of "techno-magic" is terribly off-putting to them.
maybe he was still getting used to the idea that these xenos were this advanced ( night-vision is probably very advanced tech, and cain is (almost) just as xenophobic as the rest of the imperium).
Why isn't Jurgen a quartermaster?
This has been bothering me since starting reading the series but why has Jurgen not been promoted to a job as a quartermaster? The guy is so skilled at scrounging that he could probably find those Baneblades that General Stubbs lost! I get that he wasn't well liked by the Valhallans but I'm pretty sure they would get past that if Ciaphas Cain HERO OF THE IMPERIUM vouched for him.
Short answer: Because he's Cain's personal aide, and Cain likes it that way. 'Nuff said.
Slightly longer answer: The very fact that Jurgen is anything other than a low-rank soldier serving in an artillery unit is a very fortuitous fluke; he was an undesirable soldier assigned to an equally unappreciated wet-behind-the-ears commissar as a practical joke. Both his personal hygiene habits and his pariah gene (which both make him unsettling to ordinary humans) would probably make him repulsive enough to most other people to effectively can his chances at promotion through normal channels.
The fact that Cain's personal aide is a blank keeps Cain shielded from adverse psyker influence or probing, his obstinate personality and repulsive countenance are handy at keeping at bay anyone Cain doesn't want to talk to, his dedication to his work alleviates much of Cain's workload, and finally there's that melta that he always carries around.
Amberley Vail also prefers that Jurgen stay with Cain because it makes things convenient for her as well; whenever she suspects she needs a blank handy, she can just pick up Cain, and Jurgen naturally always accompanies the commissar. It would be perfectly natural for an Inquisitor to ask for a HERO OF THE IMPERIUM!! to help her out, and the fewer people who know about Jurgen's secret, the better.
Why hasn't Vail gotten her own book yet?
This is purely me wishing for things that probably where never planned but why hasn't Amberly gotten her own spin off? It would be awesome.
She's too busy editing Cain's memoirs to write her own.
All the best parts are State Secrets. She could could tell you about them, but then she'd have to kill you.
Tell that to Eisenhorn and Ravenor. Actually, though, it's probably Mitchell who's too busy churning out those gosh-darn Cain books.
Probably because a book on Amberly Vail wouldn't be as interesting because she tends to act like a competent Inquisitor, where as Eisenhorn and Ravenor would be a whole lot more boring stories if they didn't make the situations they were in about a thousand times worse by making lots of rash and inept decisions.
Why didn't the Necrons take Jurgen to be turned into a Necron Pariah?
He has the pariah gene and they had plenty of chances to snatch him (e.g. when he and Cain were the only survivors of the attempt to blow up their teleporter in Caves Of Ice). Was he just too scruffy, even for them?
Probably because they never caught him. It's kind of hard to turn someone into a Pariah if you can't catch them to turn them into one.
But as I said, they had plenty of chances. I mean he was in their lair, had the only weapon which had a chance of damaging them and when they'd killed the fire team (and thus knew they were there) the only one with him was Cain (armed with what may as well have been a butterknife and a pea shooter). Surely they would have the means to notice a blank amongst their would-be assailants?
Except they didn't catch him when he was in the middle of their lair, and there's no evidence that the Necrons can just spot a Blank/Pariah candidate.
There is a difference between blanks and pariahs. Blanks are a natural development, while pariahs are created by the decievers Pariah gene. the effects of pariahs are also way stronger than those of blanks, just as the side effects (to the point that pariahs are so off-putting they are usually lynched as children). Jurgen is just a normal blank, so he probably isn't "good enough".
Which is now almost worthless information, because Game Workshop has a horrible time of making things like this canon and keeping it canon. More than a few sources say pariahs and blanks are the same thing now (perhaps becasue the writers didn't know the difference and Game Workshop didn't clean the air.)
That bit of fluff of human untouchables being turned into Necron Pariahs didn't exist at the time (Caves of Ice was released in '04, Do W: Dark Crusade, which said Necronized blunters were the Pariah's, came out in '06), and the way that the Pariahs acted in Co I sort of implied that Mitchell was treating them as though they operated on psychic powers or somesuch.
No, Pariahs were clearly anti-psykers from the moment they first appeared in Codex:Necrons- they had the exact same rules as Cullexus Assassins, who were human blanks and were described as being a new form of Necron being the Ctan created based on humans rather than Necrontyr. But this doesn't change the simple fact that they didn't catch him. Necrons can't just sense the presence of blanks and they simply never even noticed Cain and Jurgen while they were escaping the tomb.
At the end of Caves of Ice, Cain mentioned that Amberley spent a great deal of time debriefing the 597th and telling them to never say what they found under the mines of Simia Orihalcae. Yet in Sulla's memoirs, there are descriptions of Necron warships engaging the Gargant. This is a direct violation of an Inquisitorial order. Why wasn't the manuscript pulled? Did Sulla get in trouble for that?
IIRC Sulla's memoirs were pretty vague about the actual nature of the Necron ships, pretty much only describing their look and what their weapons did (or something like that). Perhaps that was vague enough that the inquisition saw no reason to pull it, as anyone who recognized them would have to already have known about Necrons and anyone who didn't would just assume it was an abstract description of some Imperial tech.
The memoirs were also published at a time when the Necrons had moved from shadowed threat to full blown menace in many areas. By this time the cat was well and truly out of the bag.
Has Cain Actually Shot Anyone?
And I don't mean anybody in combat, I mean as a commissar doing his duty to remove undesirables from Imperial service. I finished reading Death or Glory not too long ago, and I vaguely remember Cain mentioning he could exercise his commissarial powers and shoot someone for insubordination as a worst case scenario. Now I know that Cain has the presence of mind to keep his people in line with loyalty rather than fear, but he has considered executing people from time. Now my question, is has he actually executed anybody yet?
He executed a couple of soldiers at the end of For The Emperor (although that was because they had already been infected by Tyranids). In Duty Calls he's asked if he might have executed any friends of the PDF troops who tried to assassinate him as if it wouldn't have been a surprise, so he might have done it occassionally off camera at least.
Also from For the Emperor, he orders his unit to open fire on some loyalist PDF.
And there have been cases where he simply has no choice but to execute his own troops. Given the length of his service and the huge, varying quality and standards of discipline/morale that can be found in the troops of the Imperial Guard, executions might simply be the best way to go. As in For The Emperor a trooper threatened him and his future love, Inquisitor Vail. All in all getting shot was STILL a generous act of kindness and mercy compared to what the Inquisition's response to that would have been.
There have been occasional mentions of having to organize firing squads, so it's safe to say he has at least off screen.
Dictionary.com defines memoirs "as a record of events written by a person having intimate knowledge of them and based on personal observation," and suggested synonyms are "journal, recollections, reminiscences." From Wikipedia, one writer states "a memoir is how one remembers one's own life, while an autobiography is history, requiring research, dates, facts double-checked." Why does Amberley, who has described "the Cain archive" as memoirs, complain ad nauseum about how Cain's writing focuses on his own experiences to the exclusion of the bigger picture? Isn't that what memoirs are for? Cain's memoirs never purport to be an autobiography or a historical document, and Cain himself probably never expected anyone other than Amberley to ever read them (and maybe not even her); why is she surprised that something written for his own benefit focuses on him? This reaches Wallbanger territory for me when she criticizes him for not describing events/battles on the other side of the planet that he took no part in (as if she expected him to write a referenced history), especially when the battles in question were extensively covered by historians and Cain would not know anything that would add to those histories.
It's probably less complaining for complaining's sake and more a reminder to her fellow Inquisitors that Cain's memoirs, which in some cases are the only remaining accounts of certain events, are not necessarily completely unbiased.
Adding to the above: Whether or not an event can be verified from multiple points of view is kind of a big deal to real-world historians.
Amberley isn't writing memoirs. She's using Cain's memoirs as the primary source for the events surrounding his actions with corroborating sources to back them up and provide context. Most memoirs actually do attempt to provide some context and structure, whereas, going by Amberley's notes, there's almost no structure at all to Cain's memoirs. He's literally just typing these things out in stream-of-consciousness ramblings which would make any historian trying to edit and structure them into something useful throw a serious conniption.
Amberly isn't publishing Cain's writings just for fun, she's using it to educate fellow Inquisitors, which means she needs the commentary and background that Cain never provides. Also, Cain is patterned after Flashman, which is written exactly the same way — Flashman writes stream-of-consciousness style, while Fraser essentially cleans up after him with the intent of explaining all the useful details that Flashman leaves out. The background, not so much, as Fraser does not insert things like news stories or battle reports, but the Flashman books are not just the wacky adventures of a despicable character. They're as much historical as fiction, which is one of the reasons they are sometimes mistaken for nonfiction.
Blanks are extremely useful against Warpspawn and are so rare, psykers are a dime a dozen in comparison. So why isn't there a program to breed more of them?
Jurgen's....personality problems aside, getting enough booze and credits to seal the deal shouldn't be that hard.
Hell, artificial insemination tech probably survived in 41st century.
The Death Korps of Krieg have cloning tech right? A cloned army of Blanks has got to be useful.
Blanks were added to the human gene pool artificially by Filthy Xenos; Filthy Xenos that were trying to harm the True Enemy, but Filthy Xenos nevertheless, and everybody knows they can't be trusted and have ulterior agendas. Use the blanks as they pop up, but don't encourage them to multiply unnecessarily, that plays into the Filthy Xenos hands more than the already questionable status quo.
Which never stopped Inquisitors from breaking their own rules. They are rogues and radicals who would do it. Besides, the fluff claims that Blanks are naturally made when Pariahs were made by Xenos (canon is flimsy on this matter, though).
Also, Blanks make people extremely uncomfortable in their presence, a whole group of them probably induces suicide in the handler or something.
The surprise factor is largely the reason they have been so useful, as is the fact psykers and warpspawn are actually still extremely rare. They happen to appear often in the fluff because when they do appear, it is often something big, which is what the fluff tends to focus on. In addition, the Imperium did have an entire military organization composed of blanks, the Sisters of Silence. Outside opposing the Thousand Sons when they were still a full force legion, they never were amazingly useful for the sheer insane quantity of effort it took to amass them.
In "Sector 13," Cain's first attachment (12th Field Artillery) are cleansing Keffia of Gene-stealers, those little so-and-so's that use Unwitting Pawns to spread the mutations to future generations. There is at least one continent infested, in a war of attrition. So then why the FRAK are the soldiers being allowed into the Red Light District? It's begging for contamination! Dozens of soldiers have to be exectuted! And yet...
You are aware that this is the Imperial Guard, right?
It's entirely possible that the settlement had been investigated before, but that whoever had done so was suffering from a bad case of "It's been a long day, I hate this job, and I've been doing it for months. I don't see anything obvious, so frak it, let's call it a day."
Or the investigators were invited into a dark back room where they either got a briefcase of cash or (more likely) an implant wound in the chest.
Why does Vail hate Sulla's writing?
While...fervent, it's not really horrible. Just melodramatic.
this is Vail, she's a very no nonsense type, the style might just bother her that much.
In The Last Ditch, she complains a few times about Cain's use of military acronyms/abbreviations. If she hadn't been tagged as Inquisitorial material, she probably would have been the grammar and composition teacher no one wanted to have a class with — she has definite views on proper use of Gothic and expects everyone to follow them.
Vail will have also had to plough through Sulla's memoirs in their (no doubt lengthy) entirety, not just the short extracts repeated for context. Possibly repeatedly, if there's no index.
Probably this. It takes Sulla about three pages to describe ten minutes. She's on her second volume by about the third planet they go to. Seeing the word "doughty" twice a page for probably six or seven thousand pages would drive anyone insane. Plus Sulla worships Cain, and Vail is a pretty jealous individual.
Possibly Sulla's hero worship of Cain extends to her data storage methods: everything on one data-slate, in whatever order she recalls them.
Sulla's sections are still used to convey information to the reader. There is a limit as to how bad the writing can be made while still being somewhat informative.
Jurgen's blank powers
In the Eisenhorn and Ravenor novels, blanks working with the Inquisition are routinely issued limiters which let them turn their psychic dampening powers off so that they can work alongside psykers when necessary. Why hasn't Amberley ever tried to get one for Jurgen? Was the technology needed to create them lost in the roughly half a millennium between the end of their careers and the start of Cain's?
Half a millennium is plenty of time for it to become Lost Technology (particularly in the Warhammer 40K universe). It might also be that the few people who know of Jurgen already know of his disposition. Having it almost magically change would draw attention to him. Plus keeping him active all the time protects Cain from having his mind read (and thus protects his reputation and many, many inquisitorial secrets).
Both Eisenhorn and Ravenor are psykers, and use their powers quite extensively (Ravenor more so). It makes sense for them to limit their pet blanks range (Though I never remember Eisenhorn doing so) so they can actual function (Especially since Ravenor may flat out die without some of his psyker toys in the long term). Cain nor Amberley have this problem. It can also be noted that Jurgen's blank range seems to be much shorter then most other blanks.
Eisenhorn and Ravenor were both written by Dan Abnett, who, let's just say took certain liberties with "blanks." For comparison, Alizabeth's powers in Eisenhorn are used similar to Spear, the Black Pariah. Spear was probably the most powerful Pariah to have ever existed to start with and he was bonded to a Chaos Daemon and his powers did not work without a sample of blood from the Psyker. So, Alizabeth in Eisenhorn is more powerful than an assassin capable of posing a direct threat against the Emperor of Mankind while he was still alive and well.
I can understand wanting to research captured genestealers and frozen tyranids to figure out the best way to fight them (YMMV on whether or not doing so is a good idea, but the logic is valid enough to warrant considering it), but what possessed them to put the research facility on a forge world? If anything went wrong, a hive fleet would turn up and destroy a world that was the Guard's primary source of armaments for the subsector. Why didn't they put the facility on some minor moon or space station in the middle of nowhere with virtually no biomass outside of the beings in the facility to be eaten and nothing of value to be lost other than their research data?
Adaptus acolytes don't tend to think these things through (c.f. their reactions to Necrons) and forge worlds are the sorts of places they like to hang out. When you remove those pesky strategic and human elements and only pay attention to what techpreists actually care about a forge world makes sense (better infrastructure, plenty of space, little biomass in the wild for the tyranids to eat if they escape, plenty of other techpreists to brag about your work to, etc).
The defenses a typical forge world would have, probably makes it safer than trying it in the middle of nowhere. Also, I doubt they'd be shy about vaporizing chunks of their own world to contain an outbreak problem.
Also keep in mind that the person in charge of the research had been secretly implanted before the research even began. No doubt she used her influence and position to convince everyone else that a Forge World was the perfect place to conduct her research.
Why hasn't Cain been promoted?
According to this, the Commissariat does have a rank structure, with several levels above the standard Commissar, including Commissar-Captain, Colonel-Commissar, Lord-Commissar, all the way up to Commissar-General. Given Cain's heroics, and the fact that he often advises Lord General Zyvan, you would think that Cain would have made Lord-Commissar by now, if not Commissar-General. Even by the time of his retirement, he still seems not to have been promoted above the level of ordinary Commissar. For that matter, why hasn't Cain ever replaced his chainsword with a power sword?
I don't know about the WH40K universe proper, but; The footnotes in The Greater Good and The Last Ditch mention L-C is an informal title and Cain would probably qualify as one even though he refused to be addressed as one (earlier books note that the Commissariat is made up entirely of equals; only a tribunal of several commissars can pass judgement on one of their number). Another footnote mentioned that Commissar-Generals (like Gaunt) were rather rare and that, rather than being a higher rank, they were Commissars who were also Generals (i.e. they held a command post within the imperial guard chain of command as well as their role as The Political Officer which was outside it).
I remember those footnotes, and those would explain it if they are true. And of course the Warhammer wiki is an unofficial source, but it does cite official sources. So why does the wiki have the idea that there are ranks within the Commissariat?
Because it's one of those things that depends on the writer. The use of Commissar-General, Commissar-Captain and Junior Commissar are (as far as I can recall) pretty much restricted to the Gaunt's Ghosts novels. The title of Lord-Commissar is used in the actual Guard Codex but even there it's more of an honorific for a senior Commissar than an actual rank. The wiki pretty much lists all ranks mentioned in any source with no real indications of where they originated. The depiction of the Commissariat's organization in the Cain novels is pretty close to the way that it's depicted in the rule books. Alternatively, if you want to combine all sources, keep in mind that the Cain novels take place approximately 150 years after Gaunt's Ghosts and are set on the other side of the galaxy (the Cain novels are set in the galactic east while the Sabbat Worlds Crusade was to the galactic west). Given the distances involved (both in time and space) it's not unrealistic to assume that the portion of the Commissariat that Cain works for is organized differently than the portion that Gaunt works for.
Of the several 'ranks' mentioned in the wiki, only six are related to Commissariat. Cadets are in training, Juniors are are basically probationary Commissars, Commissars are just Commissars, and Captain through Lord describe positions a Commissar holds, rather then an actual rank. It's kind of like how a Captain of a ship doesn't necessarily have to be ranked as a Captain - If a lieutenant is is charge of a naval ship, he's stilled referred to as a Captain. As a Commissar who seems to have spent the vast majority of his time on the front lines in a combat unit (The exception being when Cain was based at Commissar headquarters, where he never seems to have been in charge of anything or anyone), Cain simply was never in a position to claim a title.
Of note, however, is that Cain does describe a method of judging 'seniority' (A common occurrence in real military situations where people of the same rank may be required to submit to one another, based on position first, and seniority if that fails). Basically, length of service, commendations, and position are added together somehow to figure out who's 'senior' in any situation. Given Cain's length of service and his distinguished career, Cain very well may have 'outranked' many Commissars who held positions such as Captain/General-Commissar, and there are likely Lord-Commissars who would defer to Cain on reputation alone. The books also don't span Cain's entire career (Yet) - It seems more then possible that when Cain was brought out of retirement by the Black Crusade he claimed a Lord tag. I don't think they bring Hero's of the Imperium out of retirement to go slogging about at regimental level at almost 200 years old.
The reason he keeps his Chainsword is the same reason he kept his Laspistol when he could have upgraded to a Hellpistol. The heavier weapons could throw off his balance and possibly get him killed in combat. Though, why he couldn't just practice with the slightly heavier weapons is never discussed.
He's practiced with the chainsword and laspistol for years before Death or Glory, and kept practicing since then. Cain isn't willing to assume he'll have that sort of time to get up to speed with a powersword and hellpistol, and between the Commissariat giving him dangerous assignments and Vail "borrowing" him and Jurgen for covert and just as dangerous missions, he's probably right.
One Per Three Thousand?
Is Cain really the only Commissar attached to the 597th? They have 3000 troops. In the games, you can have several commissars. In other books, Commissars are attached to companies (75-250 people, give or take a few hundred depending on future army organization works). Even if companies (or more likely, battalions) consisted of 500 men and women, each would need a Commissar. Wouldn't there be at least half a dozen Commissars attached to the Regiment? I don't remember any mention of other Commissars. Do you know how much paper work Cain (Jurgen) would have to fill out for that many people? Emperor knows how many disciplinary actions he would have to make with that many people. He could never get the job done alone.
Actually reading between the lines the number of Commissars assigned to a given unit is rather variable. There were none with the 12th Artillery before he was attached and Amberley mentions several times during his time with the 597th morale was high. Also Commissars don't handle all the discipline within their unit, the Guard do have their own internal structures for that. Commissars only have to get involved for serious offences and stuff that happens between units or between the Guard and the local civilians. I imagine that Cain's laid back approach to discipline helped too. By not cracking the proverbial whip he probably encouraged an attitude where the troops would help keep themselves in check. "The Commissar is a good natured sought and it's better for all of us if you don't make the kind of trouble that needs his attention," sort of things the troops may advise the FNGs.
The 12th Artillery did have Commissars before Cain arrived. It's stated in Death or Glory that they were attached at the command battery level (the artillery's version of companies, I assume), but the tyranids murdered them all on Desolatia which made Cain the regiment's Commissar. I was wrong, though, the 597th only had a thousand soldiers, but that's still one commissar for a total of four companies.
I think the idea is that while a a unit is supposed to have Commissars assigned at the company level the supply of Commissars is to small to allow for that to be done across the board. Therefore regiments that are considered untrustworthy will tend to get higher priority for Commissars while more reliable regiments (which the 597th was after Cain whipped them into shape) are considered lower priority and generally only have one or two Commissars attached at the regimental level.
Editing Errors or Emphasize
Occasionally there are sentences where the words have twice to thrice the amount of spaces between them. Is that editing errors or for emphasize? Also, in Caves of Ice, Storm Trooper Sergeant Welard is referred to as Willard at one point in the memoirs (it wasn't spoken, but written in there). Every time he was mentioned, he was referred to as Welard (he didn't even have a second name or anything), so was this a mistake or was it his second name. (Are those name even pronounced the same?)
The first point sounds like something that's moderately common and shows up at least once or twice in most books - basically, the text in a novel is both left and right justified, to keep a block of text looking regular on the page. If a line ends just wrong to make it fit neatly at normal spacing, and the last word has problems being properly hyphenated at normal spacing, then the last word is tossed forward to the next line and the previous line is spaced out slightly. You're either just noticing it more or the Cain books have had a very coincidentally high incidence of that problem. (Or you're describing something else and I'm making some wrong assumptions about what you're talking about.)
How did the Guard/Inquisition manage to purge Gravalax of genestealers without the population as a whole learning about the infestation. Even with most of the purestrains killed by Zyvan's men, along with the lion's share of the genestealers in the PDF, there still could be thousands scattered around the planet, and you can't perform mass genescans and purges without people realizing that you're doing mass genescans and purges. Despite this and the fact that the Guard and Inquisition would never leave a planet to be infiltrated by genestealers and later Tyranids if they could possibly help it, Gravalax's histories don't mention genestealer activity as part of the conflict with the Tau.
They probably disguised the genestealer purges as purging Tau loyalists. Given that this is 40K if your neighbor gets dragged away by the Inquisition for being a Tau loyalist you're unlikely to complain in case the same thing happens to you.
What I don't get is why keep it a secret? I can understand Chaos - it deals in temptation, so the less is known about its schemes the less the chance some bored/ambitios/crasy/desperate bastards might decide to reenact them. I can even understand Necrons, seing how the only coherent thought the Mechanicus seem to have about them is "Just Think of the Potential". But Genestealers do not tempt or offer anything - they just infect people without their knowledge or consent. And there's literally nothing to gain from associating with them, not even the flimsy promises of Chaos gifts - you become a mindless puppet and then you get eaten. So why not have people be aware of them, and perform genetic screanings to root out the hybrids?
Because sometimes the Imperium does things that work against their best interests but are in character for them as an organization. They don't trust their people to know about the Genestealers even if it would make sense to tell them of the threat.