Yet more of the Imperium being Grimderp for no reason. Which is where the Protectorate can step in, because that's the kind of thing Cain is genuinely offended by. He believes in the Imperium. He really does, against all reason and evidence. And everyone who is being so STUPID, destroying what in his mind the Imperium is and should be* is a traitor. And he's a Commisar, on a good day. He has training on what to do to traitors.

That gave me an idea. What if in some council meeting they discuss this and Cain complains that someone should do something about this stupid and cruel behavior. The other council members interpret this as an order leading to this:

Inquisitorial Intelligence Report: 1168196

Name: The Shadow Road

Alias: The Illuminated Path, Sanctuary of the Gifted, Saviors of the Changed, ...

Classification: Heretical Cult

Allies: The Slawkenberg Heresy

Author: Inquisitor Galen Kuraras, Ordo Hereticus

Thought for the day: Ruthlessness is the kindness of the wise.

The Shadow Road is one of the more insidious weapons of the Slawkenberg Heresy. Cells of the cult, first discovered 35 years after the Slawkenberg Uprising, have been found throughout the sector and recently even in neighboring sectors.

While they are using many different names and disguises, they always preach the same heresy:
That mutants and witches aren't dangerous abominations, but instead are just different and have unique "gifts". Therefore, its their duty to protected them from the Imperiums "cruelty".

Of course every Emperor-fearing human will react with instinctive revulsion to this suggestions, so the cult has to be very careful in recruiting new members. Consequently the cells tend to be small and growing slowly. They compensated this with strategies designed to minimize casualties. They almost never attack without preparing multiple ways to disengage. Likewise their save houses are always equipped with surveillance equipment, multiple escape routes and traps to slow down pursuers.

Moreover their members are unusual well equipped for chaos cultist. Even lower-ranking members tend to be well-trained and wear improvised but effective body armor. The higher-ranking cultists sent from Slawkenberg are often additionally equipped with subcutaneous weapons, armor, and other augmentations. Similar witches in their ranks tend to be unusual powerful and disciplined. All this makes them much more dangerous than their small number would suggest.

Once a cell is large enough to operate independently, it begins collecting mutants and witches to smuggle into Slawkenberg. How they do this varies greatly and depends on the capabilities of their cell and the situation on the planet.

On Zibictrius XII they added hidden trapdoors to the hospital incinerators, allowing them to steal newborn mutants. (see Report: 4643874)

On Barbydak Tertius they organized an uprising of the mutant slaves. Later investigation revealed that the cultists had infiltrated the shipyards, allowing them to upgrade three freighters with additional live-support, which where then stolen by the slaves and used to escape from the system. (see Report: 7646488)

On Karrios VI they faked orders to transport the psyker tithe to the space station days before the Black Ship arrived. When they docked on the station, the cultist overwhelmed the guards and fled with the psykers in several stolen shuttles. The shuttles flew to a ship hidden in the asteroid belt, which escaped before the SDF could engage it. (see Report: 5418799)

These examples illustrate how difficult it is to predict how a cell of this cult will act.

Threat assessment:

Shadow Road cells usually represent a lower threat to the Imperial rule on a world than the typical chaos cult. Since their goal is escape with the mutants they "saved" even their success usually only means a temporary disruption of the local order.

Nevertheless the Shadow Road represents a major long term threat, since the goal of the Black Commissar is obvious. He intends to strengthen his armies with hordes of mutants and witches, which cannot be allowed.

Therefor if any sign of a cult cell is found, preventing the mutants from escaping has top priority. Additionally, the escort fleets of all black ships traveling through the sector should be reinforced, as they represent an obvious target for the cultist.

So, after Cain "ordered" them to do something, the Council decided that they obviously needed the most elite teams possible for this. Of course, every faction wanted to be part of it, so they formed small teams with members of each of the four factions (Khornat commandos/trainer, Handmaiden infiltrators, Tzeentchian divinators, Borg hacker/combat engineer, ...) .

Then the borgs studied Amberleys old implants, declared them "barely adequate" and developed some "proper" augmentations for the teams. The end result is that every team member has a set of implants that would fit into a James Bond movie.

Since they can't augment the local recruits, the borgs wrote the 40k version of the anarchist cookbook so that they can assemble their equipment form local resources. Combined with the Khornat training they become proper soldiers instead of the usual cannon fodder.

The end result is that the Shadow Road acts more like a modern black ops team than the typical crazy chaos cult.

Of course, Cain will be delighted to learn that Slawkenberg will now receive a steady stream of mutants and witches of questionable sanity.