Does the ecclesiarchy answer to the inquisition?

Some Chapter Approved in WD once avout Renegade Chapters. Think it was around the time Tau were new.

The Astartes don't really "answer" to the Inquisition per se, but they usually acquiesce to the demands of Inquisitors because they know what a shitstorm would be if they outright defied the authority of the Inquisition/that the quickest way to make an Inquisitor get lost is to give him what he wants. Why spend years arguing and possibly kicking off a civil war when you could just purge whatever needs purging and being done with it?

Likewise the Inquisition can't step on the autonomy of the Astartes TOO much because they're pretty much the only thing keeping the Imperium propped up with their OP-plz-nerf warmaking abilities. A well known and respected Chapter Master is one of the only beings in the galaxy that can tell an Inquisitor "Fuck off dude, we're busy" and get away scott free.

I think both factions know that if push came to shove and a conflict broke out between them, more worlds would declare for the Astartes. The Imperium sees the Space Marines as the Emperor's avenging angels, crafted from his own flesh and therefore every individual Astartes has claim to a part of the Emperor's divinity. The Inquisition is mostly associate with exterminatus and summary executions. If you had to make a choice between being ruled by the sons of God, that ride the sky on wings of fire to destroy the enemies of mankind, or a fair facsimile of the NKVD with even less oversight, which would you pick?

Like a lot of anons said, the Adaptus Custodes is above scrutiny because they're standing next to the Emperor all the time. And the Imperium is still around. If they were suspicious, the Imperium would already be dead.

The Emperor also doesn't anwser to the Inquisition but that is a given.

Enemies of the Imperium don't anwser to the Inquisition but that's probably not what you meant.

Some Space Marine chapters with enough prestige don't have to answer the inquisition. The Space Wolves for example have told the Inquisition to fuck off more than once in the past, even getting violent.

However if generic chapter #15824 goes against the Inquisition then they're probably going to get fucked over. The Celestially Lions are an example of this when their entire chapter was given false information and killed by Inquisitorial operatives masquerading as "orc snipers"

The ordo Hereticus was founded to watch humanity. You are quoting old fluff.

Sure, but it doesnt really matter because they have enough social power and legal fuckery to make both the space jocks and the cyborg retards cringe back silently.

Now that Girlyman is in the drivers seat I bet the Inquisition is in hot water. Before their word was LAW pretty much everywhere besides the Imperial Palace and Space Marine homeworlds, now with Big Bobby G taking the reigns I bet they're about to get told "No" for the first time by someone with enough power to make it stick.

BASICALLY, NO - PRETTY MUCH EVERYONE BAR CUSTODES HAS TO ANSWER TO THE INQUISITION, BUT LIKE ALL THINGS, POWER TOO IS RELATIVE.

WHEN YOU HAVE AN ORGANISATION AS BUILT ON INFLUENCE AND POLITICS AS THE INQUISITION IS, IT'S INEVITABLE THAT POWERFUL ENOUGH ORGANISATIONS MAY BE BEYOND THE SWAY OF THE INQUISITION.

EVEN THIS, HOWEVER IS AN OVER-SIMPLIFICATION. THE INQUISITION ISN'T ONE SINGULAR BODY IN MUCH THE SAME WAY THAT 'SPACE MARINES' AREN'T ONE GROUP. THE =][= IS COMPRISED OF HUNDREDS OF THOUNDANDS OF INVIVIDUAL INQUISITORS, ALL WITH THEIR OWN SPHERES OF INFLUENCE, CONTACTS AND MODUS OPERANDI, LET ALONE PERSONAL POLITICAL PULL AND RANK.

THEREFORE, IT'S ENTIRELY POSSIBLE THAT A PLANETARY GOVERNOR OF A POWERFUL WORLD IS OUT OF REACH OF A NEOPHYTE INQUISITOR, WHEREAS THAT SAME GOVERNOR WOULD NOT BE A REMOTE CONCERN FOR A LORD-INQUISITOR.

IN SHORT: ON PAPER, AN INQUISITOR'S REMIT IS BASICALLY INFINITE. IN PRACTISE, IT DEPENDS ON A GREAT MANY FACTORS.

I APPRECIATE THIS IS PROBABLY NOT THE CUT AND DRY RESPONSE YOU WERE AFTER BUT I BELIEVE THIS IS THE BEST ONE YOU'LL GET.

ALSO MY CAPS LOCK HAS JAMMED, THIS ISN'T A SIGN OF ANGER, NOR A CUTE AFFECTATION. APOLOGIES.

And hopefully it will shut up the mechanicummies too.

On paper every Imperial instituion answers to the Inqusition because they speak with the Emperor's and have unlimited authority.
In practise they're still just people so ultimately have to convice people to go along with them.

Eh I dunno about that. The Admech/Mechanicum has always been kinda it's own thing, with it's own laws, it's own priesthood, it polices itself for "heresy", and it's such a political/military quagmire that even the Emperor himself kinda went "Eh, whatever" and didn't bother making them comply with the Imperial Truth. The Mechanicum co-operates because it wants to, not because it has to. IF the Inquisition, or anyone really (here's looking at you Girlyman) makes the Mechanicum decide to really show their asses they'd probably just blast Terra with a continent-sized archaeotech rapelaser or something. I guarantee that they have been sitting on some kind of insurance since the Treaty of Mars.

Inside the Imperial Palace the word of a Custodes is that of the Emperor and even the Inquisition has no sway.

No one HAS to answer to the Inquisition.

But everyone knows that if the big =][= in the sky comes-a-knockin' you better have some good answers ready or you will be handed a one-way ticket to pre-emptive martyrdom.

The entire =][= is based around the concept that they have all the authority (they speak in the emperor's name) but none of the resources. The only way for an Inquisitor to have any resources is to to intimidate the actual authorities to give him things OR ELSE.

Nothing is more damaging to an Inquisitor than to threaten a person in a high position of authority who then calls him out on his bluff. So while an Inquistor has perfect authority to order a chapter master around, if that chapter master says no, the only recourse for the Inquisitor is to either recruit enough forces from elsewhere in the Imperium to punish the Chapter Master for his defiance, which the Imperium can not really afford, or he has to take a significant loss of face for himself and the =][=, which is a good way to encourage the other members of the =][= to come after the idiot who threatens to unravel the entire house of cards made of threats that is the =][=.

Nope the Inquisition is still independent of Robby G fat chance of that working. Good luck convincing different inquisitors who belong to different factions. In a time of crisis like this its needed now more than ever.

Dude, he's the only living (as in, publicly, visibly alive and active) loyalist son of the Emperor of Mankind. The entire Imperium is at his disposal. Sure the Inquisition won't just roll over and give up all it's power and influence, I buy that. But Guilliman is literally the Emperor now in all but name (bet the matt ward fans are going nuts about that one) and I doubt anyone, even the Inquisition, is in any place to defy him.

>I'm certain this question has already been asked, but is there any organization that doesn't answer to the inquisition?

No. The Ecclesiarchy and the Inquisition are completely separate organizations. That being said, however, the Ecclesiarchy can still be held accountable by the Inquisition, much like any other organization in the Imperium, which means that both sides need to step carefully if there's any chance of conflict between them.

However, because of the absolutely massive overlap between the two (Adeptus Sororitas being the Chamber Militant of the Ordo Hereticus, many Inquisitors and all the Inquisitorial Stormtroopers being Schola Progenium, etc.) it is unlikely that the Inquisition would be able to or want to field a major insurrection against the Adeptus Ministorum anytime soon - but if they did, they'd likely pull a lot of the faithful with them, essentially splitting the Imperial Cult.

Of course, this was all before 40k started becoming utter skub, so things might've been retconned.

The Custodes are entirely separate, but so is the Inquisition. They are technically in the exact same position, where they both answer directly to the Emperor, and the Inquisition could choose to enforce their mandate against them.

Of course, the Inquisition does not do this, because the Adeptus Custodes would just fucking laugh in their face and tell them to fuck the right off.

>ALSO MY CAPS LOCK HAS JAMMED
Then don't post until it's fixed, dumbass

Everyone save the High Lords and the Emperor answer to the inquisition on paper. And they've even managed to disappear a High Lord ever now and then.

>Everyone save the High Lords
Part of the reason =][= exists is to keep High Lords under control.

All of this is correct. Also, it's in this where the Inquisition/Ecclesiarchy overlap becomes so important.

Whereas several major organizations of the Imperium can (and have, some many times) told Inquisitors to go fuck themselves with something rusty, such as the Adeptus Mechanicus (technically a completely separate power-structure to that of the Imperium, and a client state) or the Adeptus Arbites (because they do not recognize Inquisitorial authority as legitimate, recognize their authority as part of command structure, nor appreciate themselves being questioned), the Ecclesiarchy and Inquisition-by-proxy holds sway over the masses of mankind.

It's part of why the Inquisition can be seen almost ordering the Imperial Guard and the Imperial Navy around, or the Adeptus Arbites, and have reasonable access to the Fraterias Militia, or have the Bolter-Bitches on retainer, but at the same time, each request for anything that has anything to do with the Adeptus Astartes has to be carefully worded as a request.

Even the Ordo Malleus, so intimately tied to the Grey Knights, cannot order said knights around. They need to ask them, call for aid, or voice a formal request.

The same goes for Ordo Xenos and the Deathwatch, as far as I know, but I'm not so sure, since the Deathwatch is made up of various space marines sent there as part of an ongoing agreement - it's not a singular formal chapter. So it's possible that they defer to the internal inquisitorial chain of command as part of that.

Contrary to the meme, most Inquisitors don't order an Exterminatus every Tuesday, and plenty will acquiesce to Guilliman.

I doubt he'd shut the Inquisition down, anyway. It's pretty vital to the security of the Imperium, and it's not like it's a random upstart organization. He's likely aware it was created by Malcador on order of the Emperor.

>Adeptus Arbites (because they do not recognize Inquisitorial authority as legitimate, recognize their authority as part of command structure, nor appreciate themselves being questioned)
HERP DERP I fucking meant Adeptus Astartes.

>the Space Marine chapters are the only ones who I can imagine that are outside of Imperial Law.

No one is outside imperial law and the Inquisition only answers to itself and the Emperor.

The Admech doesnt let the Inquisition to work in their worlds, technically they do answer to the Inquisition but they deal with hereteks with their own institutions while not letting the Inquisition into their inner workings.

so hold down your shift key to de-cap faggot.

Literally nothing is outside Imperial Law, because by virtue of being a feudal empire, it doesn't even implicitly recognize borders, merely spheres of influence. In a very real sense, even xenos races that have never interacted with humanity before are beholden to imperial law by imperial logic.

I realize that may sound like nit-picking, but it's an important distinction when it comes to all these things. When the Space Marines, for example, would tell the Inquisition to go fuck itself, they would do so in a completely lawful sense.

>technically they do answer to the Inquisition
Actually, TECHNICALLY, they don't. Out of all the imperial organizations, the Mechanicus is probably the ones that have the most solid case for arguing that they are not beholden to imperial law in the same way the others are, because the Mechanicus is technically not an imperial organization, it's a client state allied and beholden to the Imperium, and the Adeptus Mechanicus waves the Treaty of Mars around like a shield whenever the Inquisition come knocking.

But if there's a legitimate issue, the Magi allow the Inquisition in, simply because to do otherwise would be tantamount to heresy, and it is in the best interests of most Magi to actually avoid hereteks operating in their midst, anyway.

But just like with the Adeptus Astartes, if the Inquisitor is belligerent, they can tell him to fuck the right off, or insist that some other Inquisitor investigates, simply out of spite and pride.

And in the meantime, they'll likely take care of it themselves, because like you say, they have their own organizations, and they really don't want the Inquisition running around, Treaty of Mars or not.

Which is kinda strange, since technically the =][= has Admech acolytes, which means they will also have Admech Inquisitors, even so I cannot remember a single piece of fiction that depicts one as such. I imagine if the =][= really wants to investigate on an Admech world, they are gonna sent a specialist, who is Admech himself, just to not piss the cogboys off too much; or more likely simply fail to inform them of their ongoing investigation.

Then again even the =][= should know better than to stick their hands into the nest of super-secretive autistic hornets that is the Admech and expect to receive more than the sound of
>M-Muh secREEEEEEEEEEEEEEEEEEEEE
and all the servitors on board the =][= vessel to suddenly switch their setting from "HUG" to "MINCE".

In theory every organization within the Imperium answers to the Inquisition. Even the Inquisition itself answers to the Inquisition, with them prosecuting heretics and radicals within their own ranks constantly.

In practice, however, while most organizations still do answer to them, certain ones can often get away with telling the Inquisition to go to hell.

I'm think the Adeptus Custodes, while they should be monitored in theory, aren't ever actually approached by Inquisitors on the fact that they're literally the bodyguards of the Emperor's decaying body. If they were I'd imagine the Custodes wouldn't give them the time of day either unless it was incredibly important to the life of the Imperium/Emperor.

Space Marines should answer to them in theory, but in practice they don't do it as much as the Inquisition would like. While often the Inquisition brings up matters that the Space Marines may actually fine important, like hunting a well known heretic or eliminating a genestealer cult, sometimes they demand things that the Space Marines find morally wrong to to them. In these situations they're liable to either find some excuse to not do it or actually confront the Inquisition on their bullshit, like how the Space Wolves nearly started a civil war over them putting civilians on Armageddon into death camps.

While there's actually an entire Ordo made for the purpose of monitoring the Adeptus Mechanicus, in actuality the Mechanicus tells them to fuck off frequently. This is because one, the Mechanicus likes to have it's own autonomy as their own state, and two, the Mechanicus will prosecute heretics within their own ranks anyway, and are probably better at it for the fact that what the Mechanicus may think is heresy isn't what the Inquisition thinks is heresy.

So in the end, some major parts of the Imperium rarely listen to the Inquisition.

>Does the ecclesiarchy answer to the inquisition?
Officially, no. They answer to the high lords of Terra.
However, the Inquisition is allowed to investigate and shoot whoever they damn well please, so long as they're right.
>is there any organization that doesn't answer to the inquisition?
In theory, no.
In practice, they don't ask the Astartes about heresy or technically being mutants, and the Astartes don't cecede from the Imperium, or 'accidentally' step on the Inquisitor's toes and crush them flat. It's kind of hard to enforce the laws of the Imperium on 8' tall super-soldiers outside of the command structure and who wear power armour habitually. Much like in theory, the Inquisition can command entire chapters of Marines to do whatever they want, but in practice they have to ask nicely to get a few squads to a company to 'cooperate'.
The Custodes answer to the Emperor and nobody else.

>but none of the resources
It's canon that they have their own private army, and that Inquisitors can make their OWN private armies because Fuck You Imperal Law, I'm A Motherfucking Inquisitor.

>Admech acolytes, which means they will also have Admech Inquisitors
Unless it's some skub newfag shit, Acolytes never really become Inquisitors, or at least extremely rarely. But either way, an acolyte serves the Inquisition - whatever organization they were a part of before doesn't matter as much, although they could often maintain all their ties.

Acolytes are secret, so it shouldn't cause issues, but an overt/recognized Inquisitor of AdMech origin likely loses all AdMech authority.

But, then again, it's an imperial, feudal system; it's entirely possible you can hold multiple titles. The fact that you hold the title of Magus within the AdMech doesn't necessarily mean that you lose any of your authority of the title of Inquisitor. This would, of course, mean that AdMech Inquisitors would be of tremendous value to the Inquisition, provided that they are of high enough stature.

It also could create a much less useful issue, though. I can't imagine that that many AdMechs that become Inquisitors actually have very high positions within the AdMech, so I can easily see an Inquisitor of AdMech origin trying to negotiate with a Magus, only for the Magus to sneer at him; "Was there anything you wanted, *Enginseer*?"

The more I think about it, the more I see the latter (titles are absolute unless actually rescinded) rather than the former (implicit loss of authority due to command structures) to be the most likely, because that's how feudal power-structures usually work, and it's part of why so many in the Imperium (and sometimes in history) have such ridiculous titles.

At some point, I think that Mike 14-88/BE, Lord-Inquisitor of Ordo Chronos, King of Sekbeth, Admiral of the Trojanus Crusade, Destroyer of the vile Daemon-Prince of Elrokk, Absolver of the Great Paradox, struck "Third-Grade Enginseer of the Cult Mechanicus" from his list of announced titles.

>In theory, no.
In theory yes, you mean. In practice, no.

Hmmm, going by the Dark Heresy stuff (and please correct me if I'm wrong), an acolyte may, if he shows promise, be promoted to the rank of interrogator and from that point on, again after proving his worth, might be promoted to the rank of Inquisitor himself, if he can amass enough clout in the ranks of the Inquisition.

After all, there must be a way for the Inquisition to replenish their ranks and I know of no rule that excludes the Admech from attaining that rank.

Also you will find that at the point where a priest of mars will have enough resources and connections to become an Inquisitor, he will also have ascended through the ranks of the Admech as well. So he will not be Enginseer third-grade, but most likely an Arch-Magos of some division. Generally acolytes are not officially removed from whatever organisation they were recruited from, as the Inquisition does not need to advertise who they recruit for obvious reasons and a high ranking acolyte is more useful to the Inquisitor.

There is, however, the general trouble of having Admechs in your ranks: They will always retain a certain loyalty to the Admech, no matter how much power and trust you give them. The Space Marines have the same problem with their Tech-Marines, who all undergo special training and indoctrination on Mars. They will simply not divulge Admech secrets to you, no matter what rank you can pull.

>it's a client state allied and beholden to the Imperium
No it isn't. The Mechanicum gave up their independence in the Binary Succession. They are part of the Imperium now.

It's been years since I last saw the Ascension book, but if I recall correctly techpriest careers don't actually have access to the Interrogator career and can't become full Inquisitors (just as all the other classes don't get to become Magi).

I feel like the who's in charge line for custodes goes:
1. Big E
2. Malcador
3. Loyalist primarch

With the top two unavailable I suspect Big G will get some support if mostly a bodyguard in the attempt to make shit not broken. The custodes only seem to give a fuck about things that are not oiling the Emperor if shits broke.

Two primarch and they will probably be told to fuck off until the pecking order is established no HH 2: electric primarch boogaloo

God I love the Celestial Lions. I want to start a Primarines army at some point because I'm a huge faggot for those minis and I'm torn between the Celestial Lions, Iron Fists, and Lamenters.

Furthermore, the Custodes' sphere of activity is so limited (a self-imposed limit, they could do whatever the fuck they want but they mostly don't) that they don't come into conflict too much.

In the announcement for them it did specifically call out reviving dead chapters so I think Celestial Lions would be baller.

Maybe a few original marines as the few veterans or chapter master? They did have like 8 survivors right?

The inquisition and ecclesiarchy are different structures. The Imperium is a bureaucratic nightmare, don't forget. The ecclesiarchy answers to the high lords of terra as others have said, not the inquisition.

The inquisition has the authority overall to do whatever they please, but individual inquisitors may or may not. If a junior inquisitor started pushing people around their would be "accidents" or at the very least they would be told off. A more high ranking inquisitor with more influence and resources would command more respect. Overall though, inquisitors would work to build relationships more than just show up and act tough, though they would do a bit of the latter when the need arises.

The space marines are well known for not bowing to inquisitors, as others have pointed out. In one of the books if I recall an ultramarine cuts off a lesser inquisitor's hand because he was mouthing off after being told to GTFO.

The Daemonhunters codex explained that acolytes were the helpers of inquisitors and could be chosen from whomever the inquisitor wanted. If an inquisitor really liked an acolyte and thought they were good enough to deserve it, they could get promoted, and eventually they could put in a recommendation. I'd have to double check, though I believe the 6E inquisition book goes into more detail about it as well.

For sure most acolytes never ascend beyond that rank. They either die in their service, or presumably retire, but this is the grim darkness of the far future, so I am guessing retirement is rare.

Long ago, the fluff had hints of an "Ordo Astartes", which was an ordo minoris dedicated to researching methods to be used against renegade Chapters, etc.
It's not beyond the limits of inquisitorial paranoia that there may be a similar group dedicated to the Custodes...

in theory, only the custodes does not answer to the inquisition

in practice, there are many people who are somewhat off-limits to the inquisition, simply because they are too powerful and/or important for the inquisition to touch, astartes like the celestial lions were easily bullied, they tried to bully the space wolves but that lead to a war, they certainly would not touch the black templars or the ultramarines

I read this in the DoW Dreadnought voice.

read in this voice

>MY CAPS LOCK HAS JAMMED
>not reciting the canticles of the Machine God and applying the sacred unguents of maintenance to repair the non-functionining key of linquisitic transmission
Heretek!

But other than that, this user is 100% correct.

The only confirmed survivor was one marine forced to take the oath of chapter master by the Black Templars, I think. They sent him to his chapter's home planet with a BT escort to start rebuilding his chapter. Since it was mentioned that regular marines can undergo the upgrade process to become primarines, I was thinking about just handwaving him as having elected to have the procedure after Bobby G sent him primarines made from the Lions' gene stock.

I wonder just how many Inquisitors the Custodes have had to kill, for trying to force their way into the Emperor's throne room for a meeting.

Presumably there was a small handful left on their homeworld to protect their assets there

>it is unlikely that the Inquisition would be able to or want to field a major insurrection against the Adeptus Ministorum anytime soon - but if they did, they'd likely pull a lot of the faithful with them, essentially splitting the Imperial Cult.

I get the feeling in that situation the SOB would go 'No fuckers, stop this. We are not having a second age of Apostasy' if it looked to be a full on civil war rather than an individual member of a group playing funny buggers.

Going by Dark Heresy stuff, techpriests can't become inquisitors.

...

reminder that Goge Vandire was originally the boss of the Administratum, he was a bureaucrat, not a man of faith.

Read the post again.
In theory, there is nobody that does not answer to the Inquisition.
In practice, you can't tell the space marines what to do, because they're autonomous. You can ask nicely and advise, and they'll follow it if it's in their best interest.

Learn to fucking read.

>inquisitors taking a nap
>hears doorbell
>opens door revealing squad of primarines in celestial lion heraldry escorting the chapter master, wearing terminator armor
>"hello, we would like to share a story about orkish snipers"

Maybe the autists compile because if they tried to start shit terra would let loose the void dragon and obliterate mars in seconds. Kinda like a MAD deal of the Cold War but in better terms between the parties as both need each other to exist in that shithole of galaxy.

While it is correct that in the Dark Heresy Ascencion book Techpriet don't have the Interregator and Inquisitor path open for them. There are still guys like Cyrrik Scayl who was a Magos and then went to become an Inquisitor. So I would argue it is not impossible for a techpriest whatever stand he is, to become an Inquisitor.

ehhemmmm....
cough, cough

>Abooboo, the meanie big letters trigger me.
Buy some balls.

While you are right regarding the Mechanicus Notinquisition. Technically have to answer the big I, too.

Even in death, I still write reasonable stuff.

De jure, only the Emperor and Custodes.
De facto, anyone with enough power to deter from total war.

If the lot of you can´t even make this distinction, most of W40k and real world politics probably do not make much sense to you

This is pretty accurate, and I'd say the thread pretty much has it - in theory, everyone is answerable to the inquision, bar the Emperor himself and possibly Custodes, but in practice there's a fair few individuals who the inquision cannot just boss around - spheres of influence are very much a factor

From the looks of it though, to even think about doing down against an inquisitor your area of authority/ability to wreck shit needs to be "a planet" or higher - given inquisitors have licence to order exterminatus the command over/the ability to wreck a planetary system seems a good "buy in" level to sit at the inquisitor's table and talk to them somewhat as equals

Space marines do answer to inquisitors, but different chapters have more or less authority, for example, a first founding chapter would have to commit heresy of the highest level to face inquisitorial sanctions, whilst a 13th founding could feasibly be wiped out for perceived slights.

As to the AdMech, there's a minor ordo, the ordo Mechanicus, if memory serves, which is supposed to oversee it.

Why they do technically answer to the big I. It's in the Inquisition best interest to report their findings to the Ordo Juris, and let them handle it.

Quick question. Can a Hereticus Inquisitor sentence a deathwatch marine to death for being possibly tainted by chaos? The Watch Master is able to step in if needed.

I imagine that for suspicion of taint, an Astartes is too valuable to just blam right there. I think you need to be interrogated by your chapter's Librarian & Chaplain first.

Asking for a Deathwatch session that I have no idea how to proceed with on Sunday.

He could probably order some serious interrogation and examination (consider the case of the IF's Lysander after he broke out of an IW fortress and returned to the chapter, which also included a long stint being lost in the warp), but outright ordering execution would be exceedingly unlikely unless the marine has obvious corruption. You are right in thinking that an astartes is FAR too valuable to blam right there, but a long period of painful inspection and interrogation would probably be in order

The Ordos of the Inquisition tend to reflect the general interests, peer groups and influences of Inquisitors rather than hard and fast legal boundaries. If they come across something they deem evil they're going to try and deal with it even if its not in their normal wheel house - a Malleus Inquisitor isn't going to ignore a Genestealer infestation, a Xenos isn't going to let daemonology slide. Hereticus actually have the broadest remit dealing with Imperial institutions (the Enemy Within), so Space Marines who have gone off the reservation are actually right up their street. The thing is that it boils down to what says - power is relative. Is it obvious that this has to be done? Can the Inquisitor get away with it (either because they're so powerful and well-respected or the Marine/Chapter is weak)? Have they got the sheer balls to do it and survive any repercussions.

If it were me, and this is what you might call an "average" Inquisitor rather than a Lord or a sector hero, and the Marine in question isn't obviously sprouting spider legs or raving about how the Emperor is a false god, has it right. Serious business interrogation coupled with getting their side of the story ready to give to the local Deathwatch Fortress Commander. Remember, Marines, even Deathwatch marines, generally don't have the kind of esoteric, in-depth knowledge of heresy and other weird shit that an Inquisitor has beyond what's needed to kill things really hard. Inquisitors aren't well liked, but if they can show they know what they're doing then they will be listened to.