Mechanically, hoes does Mind Cleansing work? Does it reduce insanity and/or Corruption? Can you leave an "These memories have been deemed a Moral Threat, and seized by agents of the Holy Ordos. Inquisitorial authority or security clearance Vermillion required to investigate further. Proceed at your peril" in the target's mind in case others come searching?

Can PCs with Erasure perform it, or is there more to it than that? I seem to recall that in the MT codex (40k), they used a chair, brain probes and strange liquids, but that does not seem convenient for the Inquisition to perform on whole hab-blocks.

What availability should it be? My PCs want to perform it on someone who has seen waaay to much, but that they still need to much to kill (he's the best hired assassin they have).

The inquisition traditionally DOESN'T perform it on whole hab blocks. It is restricted to those deemed useful. The definition of useful is rather elastic, similar to everything carried out by the Inquisition. But after the First Armageedon War, the entire surviving civil population was herded into "refugee and resettlement camps" and given "vaccinations" that rendered them sterile, and not one of them had even SEEN the chaos forces. All they knew was tje planet had been attacked and the pdf had defeated the invasion but at great loss.

Life is exceedingly cheap in M.41. One inquisitorial quote appropriate is "Some may question your right to kills millions. Those wjo understand would question your right to let even one live!"

There are no rules for the process of Mind-Cleansing specifically, though in the DH 1 Inquisitor's Handbook there is the Mind-Cleansed Origin.

I don't think any instance of Mind-Cleansing has ever been performed on-screen in any 40k fiction, so you'll have to make it up as you go along.

I suggest some special equipment: strap the guy to a chair, shave off hair and stick in some neuro-plugs, hook them up to some kind of IV-drip, get at least one, preferably several telepaths with Erasure, and after a painful, hours-long process you're left with a shivering, confused subject and can begin revalidating. Once they're back up to strength, they should hopefully be the same they were before, just with several hours/days/weeks of memory removed. If something went wrong, they might have developed permanent brain damage.

For rules ideas: choose the length of memories to remove. After a successful procedure (and hours or days of getting their strength back and getting their jumbled memories back in order), the subject has lost all Insanity and Corruption Points gained during the erased period, but not Malignancies and Mutations. Gain a flat 1d5 or 1d10 Insanity Points, or tie it to a Willpower Test or Intelligence Test made by the people doing the Mind-Wiping.

Leaving notes in the subject's brain sounds good - perfectly in line with how mind-scrubbing has been portrayed in 40k fiction.

The inquisition traditionally DOESN'T perform it on whole hab blocks. It is restricted to those deemed useful. The definition of useful is rather elastic, similar to everything carried out by the Inquisition. But after the First Armageedon War, the entire surviving civil population was herded into "refugee and resettlement camps" and given "vaccinations" that rendered them sterile, and not one of them had even SEEN the chaos forces. All they knew was tje planet had been attacked and the pdf had defeated the invasion but at great loss.

Life is exceedingly cheap in M.41. One inquisitorial quote appropriate is "Some may question your right to kills millions. Those wjo understand would question your right to let even one live!"

Really? I'd always thought that they performed a limited form of mind-cleansing to remove some knowledge when killing everyone isn't an option (subtlety is of the essence in these cases) - sometimes on entire hab-blocks who had witnessed critical Inquisition operations or some kind of Moral Threat.

For the moment, I'm thinking that a timeframe of 2 weeks + 1 week per DoF on a WP+0 test (and -1 per DoS, min 1) should be good for a full mind-cleansing. Before the end of that time, the character is either being worked on or recovering, and cannot perform any actions.

I have no idea what the availability of a full mind-cleansing should be - does anything else compare? Can anyone apart from the Inquisition provide it?

The inquisition traditionally DOESN'T perform it on whole hab blocks. It is restricted to those deemed useful. The definition of useful is rather elastic, similar to everything carried out by the Inquisition. But after the First Armageedon War, the entire surviving civil population was herded into "refugee and resettlement camps" and given "vaccinations" that rendered them sterile, and not one of them had even SEEN the chaos forces. All they knew was tje planet had been attacked and the pdf had defeated the invasion but at great loss.

Life is exceedingly cheap in M.41. One inquisitorial quote appropriate is "Some may question your right to kills millions. Those wjo understand would question your right to let even one live!"

Really? I'd always thought that they performed a limited form of mind-cleansing to remove some knowledge when killing everyone isn't an option (subtlety is of the essence in these cases) - sometimes on entire hab-blocks who had witnessed critical Inquisition operations or some kind of Moral Threat.

I can't see why the Inquisition would mid-cleanse a whole hab block when they could just simply purge the lot of them and have 0 risk of anyone remembering anything. You talk about subtlety being imperative in this case but think of the time and effort involved in mind-cleansing a whole hab block - that's an awful lot of hab proles to have to carefully remove dangerous memories from. Hives can be dangerous and unstable places, hivequakes are a common threat and fire would be lethal to any areas caught in it, why not - if subtlety is so important - send in Acolytes to stage a hive quake or have the hab block 'accidently' burn down with absolutely no survivors.

Personally, it goes against my view of the 40K setting and the Inquisition in general that they would bother keeping anyone alive who'd seen "citical Inquistion operations" or "Moral Threats" who live in a hab block.

After all; "Innocence is an illusion" .

Really? I'd always thought that they performed a limited form of mind-cleansing to remove some knowledge when killing everyone isn't an option (subtlety is of the essence in these cases) - sometimes on entire hab-blocks who had witnessed critical Inquisition operations or some kind of Moral Threat.

I can't see why the Inquisition would mid-cleanse a whole hab block when they could just simply purge the lot of them and have 0 risk of anyone remembering anything. You talk about subtlety being imperative in this case but think of the time and effort involved in mind-cleansing a whole hab block - that's an awful lot of hab proles to have to carefully remove dangerous memories from. Hives can be dangerous and unstable places, hivequakes are a common threat and fire would be lethal to any areas caught in it, why not - if subtlety is so important - send in Acolytes to stage a hive quake or have the hab block 'accidently' burn down with absolutely no survivors.

Personally, it goes against my view of the 40K setting and the Inquisition in general that they would bother keeping anyone alive who'd seen "citical Inquistion operations" or "Moral Threats" who live in a hab block.

After all; "Innocence is an illusion" .

Agreed. The time, resources and personnel it would take to mind cleanse a whole hab block would not be worth the effort and would not be more subtle.

Far easier to distribute a story about a disease quarantine or major chemical spill, then lock down the area, kill everyone and say their were unfortunately no survivors.

Considering the Inquisitions is willing to purge entire guard regiments for seeing too much a hab block worth of civilians would be considered far less worth preserving than that.

It's the inquisition: killing the witnessess is cheaper, easier and more efective than mindcleansing. Also: More grimdark.

The only reason they bother at all with mindcleansing space marines (drafted into the inquistion's service when the Grey Knighsts aren't available) is that astartes are valuable and it takes a while to produce new marines. (also some chapters don't appreciate it if their men go missing wholesale in the inqusitions service.) Any imperial guard wgho had the misfortune of getting drafted by the ordo malleus will simpley get executed post operations because of threath of corruption.

Some might get picked out for an inquisitor's retinue of for inquisitorial stormtroopers, but most get "the emperor's mercy".

Really? I'd always thought that they performed a limited form of mind-cleansing to remove some knowledge when killing everyone isn't an option (subtlety is of the essence in these cases) - sometimes on entire hab-blocks who had witnessed critical Inquisition operations or some kind of Moral Threat.

I can't see why the Inquisition would mid-cleanse a whole hab block when they could just simply purge the lot of them and have 0 risk of anyone remembering anything. You talk about subtlety being imperative in this case but think of the time and effort involved in mind-cleansing a whole hab block - that's an awful lot of hab proles to have to carefully remove dangerous memories from. Hives can be dangerous and unstable places, hivequakes are a common threat and fire would be lethal to any areas caught in it, why not - if subtlety is so important - send in Acolytes to stage a hive quake or have the hab block 'accidently' burn down with absolutely no survivors.

Personally, it goes against my view of the 40K setting and the Inquisition in general that they would bother keeping anyone alive who'd seen "citical Inquistion operations" or "Moral Threats" who live in a hab block.

After all; "Innocence is an illusion" .

Agreed. The time, resources and personnel it would take to mind cleanse a whole hab block would not be worth the effort and would not be more subtle.

Far easier to distribute a story about a disease quarantine or major chemical spill, then lock down the area, kill everyone and say their were unfortunately no survivors.

Considering the Inquisitions is willing to purge entire guard regiments for seeing too much a hab block worth of civilians would be considered far less worth preserving than that.

Plus a hab block full of mind cleansed people would be quite obvious that something has happened, and the mind-cleansed homeworld option in Inquisitors Handbook made it clear that some memories do survives the cleansing.

Letting them live is just too much of a risk.

A full mind cleanse, or even erasing a few memories is only used when leaving the subject alive provides enough of a benefit.

As for how they kill everyone, releasing a disease to kill everyone would help sell the cover story of a disease. Question is: Why does the Inquisition want to deny this purge ?

Orbital bombardment would also take care of tainted objects. Then send the current planetary governor a simple message: The Inquisition has purged <location> for heresy. Execute anyone who wants to know more..

Okay - I suppose I'll just have the PCs kill everyone. The Hierophant will probably love it - a good heretic-killing kill squad mission, just like old times

But is there any way to figure out the availability of a full mind-cleansing? Is something similar mentioned in any supplement?

For the moment, I'm thinking that a timeframe of 2 weeks + 1 week per DoF on a WP+0 test (and -1 per DoS, min 1) should be good for a full mind-cleansing. Before the end of that time, the character is either being worked on or recovering, and cannot perform any actions. I presume that qny medium-sized Inquisitorial facility is capable of performing a mind-cleansing (or maybe even reconditioning one!), but I wonder if AdMech or the Adeptus Astra Telepathica can do similar things.

For the moment, I'm guessing that it would be Extremely Rare - Near Unique if I'm wrong and no-one else can do it.

Okay - I suppose I'll just have the PCs kill everyone. The Hierophant will probably love it - a good heretic-killing kill squad mission, just like old times

But is there any way to figure out the availability of a full mind-cleansing? Is something similar mentioned in any supplement?

For the moment, I'm thinking that a timeframe of 2 weeks + 1 week per DoF on a WP+0 test (and -1 per DoS, min 1) should be good for a full mind-cleansing. Before the end of that time, the character is either being worked on or recovering, and cannot perform any actions. I presume that qny medium-sized Inquisitorial facility is capable of performing a mind-cleansing (or maybe even reconditioning one!), but I wonder if AdMech or the Adeptus Astra Telepathica can do similar things.

For the moment, I'm guessing that it would be Extremely Rare - Near Unique if I'm wrong and no-one else can do it.

Seems very fast. I'd say months at the least.

And yes, your PCs should just murder everyone. They should even probably inform the planetary governor that he needs to do it and just oversee the operation (subtley?). Pretty standard stuff, imo.

Maybe the inquisitor has a purge-squad that he uses for such things.

Remember that there are two parts to a mind-cleansing. The first is the wiping of everything in the mind. That's the easy part. If you get it wrong, you just try again. Though you'll need to decide between leaving them able to breathe on their own or having a machine do it for a while.

The difficult part is then putting in a new stable personality. Because you'll have to replace everything starting with their ability to walk.

Plus a hab block full of mind cleansed people would be quite obvious that something has happened, and the mind-cleansed homeworld option in Inquisitors Handbook made it clear that some memories do survives the cleansing.

Letting them live is just too much of a risk.

A full mind cleanse, or even erasing a few memories is only used when leaving the subject alive provides enough of a benefit.

As for how they kill everyone, releasing a disease to kill everyone would help sell the cover story of a disease. Question is: Why does the Inquisition want to deny this purge ?

Orbital bombardment would also take care of tainted objects. Then send the current planetary governor a simple message: The Inquisition has purged <location> for heresy. Execute anyone who wants to know more..

For one, would the Imperium want to admit a whole hab block could be corrupted at once?
Two, many Inquisitors prefer to work under the radar.
Three, targeting one part of a hive with orbital bombardment would be idiotic as there would be significant collateral damage. Bombardments are not exactly scalpels. If the hab block is anywhere other than on the edges you'd have to blast through unrelated sections and risk destroying the entire hive. Just because the Inquisition technically has unlimited authority, in practice, there can still be significant political fallout from taking an action this drastic, destructive and unnecessary.
Four, unless the structures are also tainted why destroy a perfectly reusable hab block and any manufactorum or other assets located there. After everyone is dead just move some new people in.
Five, civil unrest and revolt is still something the Imperium has to worry about quite a bit. Better for the people to think the deaths were accidental than to know the truth.

1 - Exterminatus is an Inquisitor admitting that an entire planet is beyond saving.

2 - Sometimes subtle methods will not work.

3 - True. Which is why it needs to be saved for when it is necessary.

4 - Depends on what caused the need for the purge. If it's tyranid then purging all organic life while leaving the hab block intact is probably sufficient. If it's chaos, the building is going to be tainted.

5 - Sometimes subtle methods are insufficient.

Okay - I suppose I'll just have the PCs kill everyone. The Hierophant will probably love it - a good heretic-killing kill squad mission, just like old times

But is there any way to figure out the availability of a full mind-cleansing? Is something similar mentioned in any supplement?

For the moment, I'm thinking that a timeframe of 2 weeks + 1 week per DoF on a WP+0 test (and -1 per DoS, min 1) should be good for a full mind-cleansing. Before the end of that time, the character is either being worked on or recovering, and cannot perform any actions. I presume that qny medium-sized Inquisitorial facility is capable of performing a mind-cleansing (or maybe even reconditioning one!), but I wonder if AdMech or the Adeptus Astra Telepathica can do similar things.

For the moment, I'm guessing that it would be Extremely Rare - Near Unique if I'm wrong and no-one else can do it.

I would probably say near unique. At least the complex way the inquisition does it.

The ad mech might be able to accomplish something similar through lobotomy and replacing organic bits with tech, but probably leaves the person even more emotionless/servitor like.

The astra telepathica might be able to erase memories or implant commands but it might be more tricky for them to both erase everything and then replace everything with a new false identity.

It seems the normal procedure involves a combo of psychic powers, drugs and tech so they all can probably halfassedly do part of the procedure but getting the full effect requires all three.

Remember that there are two parts to a mind-cleansing. The first is the wiping of everything in the mind. That's the easy part. If you get it wrong, you just try again. Though you'll need to decide between leaving them able to breathe on their own or having a machine do it for a while.

The difficult part is then putting in a new stable personality. Because you'll have to replace everything starting with their ability to walk.

Plus a hab block full of mind cleansed people would be quite obvious that something has happened, and the mind-cleansed homeworld option in Inquisitors Handbook made it clear that some memories do survives the cleansing.

Letting them live is just too much of a risk.

A full mind cleanse, or even erasing a few memories is only used when leaving the subject alive provides enough of a benefit.

As for how they kill everyone, releasing a disease to kill everyone would help sell the cover story of a disease. Question is: Why does the Inquisition want to deny this purge ?

Orbital bombardment would also take care of tainted objects. Then send the current planetary governor a simple message: The Inquisition has purged <location> for heresy. Execute anyone who wants to know more..

For one, would the Imperium want to admit a whole hab block could be corrupted at once?

Two, many Inquisitors prefer to work under the radar.

Three, targeting one part of a hive with orbital bombardment would be idiotic as there would be significant collateral damage. Bombardments are not exactly scalpels. If the hab block is anywhere other than on the edges you'd have to blast through unrelated sections and risk destroying the entire hive. Just because the Inquisition technically has unlimited authority, in practice, there can still be significant political fallout from taking an action this drastic, destructive and unnecessary.

Four, unless the structures are also tainted why destroy a perfectly reusable hab block and any manufactorum or other assets located there. After everyone is dead just move some new people in.

Five, civil unrest and revolt is still something the Imperium has to worry about quite a bit. Better for the people to think the deaths were accidental than to know the truth.

1 - Exterminatus is an Inquisitor admitting that an entire planet is beyond saving.

2 - Sometimes subtle methods will not work.

3 - True. Which is why it needs to be saved for when it is necessary.

4 - Depends on what caused the need for the purge. If it's tyranid then purging all organic life while leaving the hab block intact is probably sufficient. If it's chaos, the building is going to be tainted.

5 - Sometimes subtle methods are insufficient.

We were specifically discussing one hab block that was corrupted in such a way that mind cleansing (if it were economical) would solve the problem. I was simply giving reasons why the inquisition might want to deny a purge under the listed circumstances. Under these conditions a lance strike would be massive incompetent overkill that would make you significant enemies. These kinds of purges are practically perfect examples of things the arbites are for.

1- Most people in the Imperium do not know about Exterminatus and even when employed, if too many other inquisitors or other imperial commanders think is was unnecessary there will be hell to pay. This is also only really utilized when a planet is already clearly lost.

2- I wasn't suggesting killing them in a subtle way exactly just releasing a cover story. For example "quarantine" the area using the lie that there is an outbreak or chemical spill then send in arbites to kill everyone with guns and burn/incinerate the bodies. Done, problem solved. People saw rhinos go in (relief effort *lie ) and maybe a few people shot trying to break quarantine. They don't even need to know the Inquisition was involved.

3- The specific situation we were discussing it would not be necessary. It pretty much would require the area to be swarming with daemons for this kind of destruction to be worth it.

4- Even if its tainted taking a flamer to it or more localized demolitions would make more sense than blasting the hive apart from orbit causing untold amounts of additional collateral damage. Hive cities aren't exactly super stable and many already suffer devastating hive quakes so one poorly placed lance strike to the middle could bring half the hive crumbling to the ground.

5- see #2. Plus literally anything is more subtle than an orbital bombardment on a populated hive city.