Something I posted on the Black Industries section of the Black Library forums, at the beginning of the year. It's been copied to Dark Reign since, but it's been sitting in the depths of their archives for some time, and I thought it could do with a re-airing.
It consisted of two posts, the first of which is below:
The Primary Psykers of the Scholastica Psykana are strictly organised, as a means to monitor such a dangerous and valuable commodity. Being strong enough to potentially resist Daemonic Intrusion by themselves, they are not soul-bound, and are given a degree of organisational autonomy beyond that of the more numerous Astropaths/Secondary Psykers, who must be Soul-Bound in order to protect them from the Enemy Beyond.
This autonomy exists primarily because they are the foremost experts in the Imperium on the application, development and risks of psykers, and thus are best placed to decide where their unique talents are most effectively used.
However, that same autonomy is also a grave responsibility - the Scholastica Psykana could not tolerate corruption within their ranks, and every effort must be made to prevent if possible, or eliminate if necessary, any taint that infiltrates their ranks.
Within the Calixis Sector, and likely a great many other sectors across the Imperium, the Scholastica Psykana operates as a series of interlinked Covens - individual cells of similar Sanctioned Psykers operating under the auspices of a single more senior Psyker who in turn belongs to another Coven of higher status.
These Covens are largely isolated from all Primary Psykers outside their number, connected to the rest of the Scholastica Psykana Calixis by their leader, in a structure very similar to the 'cell-based' structure used by many heretical cults, and for similar reasons: If one Coven is compromised, others are shielded by ignorance from it due to a lack of direct contact.
These Covens are organised around groups of similar Psykers, as already stated, defining them according to status, disposition, relative potency, and dominant discipline. Thus, one Coven may consist entirely of Savants Militant specialising in Telekinesis (led by a single Savant Warrant Telekine, who in turn reports to his own Coven of Savants Warrant), while another may consist of Scholars Medicae specialising in Biomancy, led by a single Scholar Arcanum Biomancer.
These Covens are both internally and externally policed - Psykers are monitored by their peers and their superior alike, and being responsible for a Coven that becomes irrevocably tainted is both a sign of gross misjudgement and a crime punishable by any number of punishments, the least of which is death by immolation. As a result, it is in the interests of every psyker to ensure the loyalty and purity of his peers and inferiors, lest they be condemned for the heresy of negligence.
Covens generally consist of a dozen or so Psykers (the ideal is 12 per coven plus a leader), who are all in as regular contact as possible, not just for monitoring, but to share discoveries, help each other learn and simply interact as peers and colleagues.
The Covens Militant
Also known as 'Battle Psykers', 'War-witches' and a variety of less flattering names, the Savants Militant and their ilk devote their studies towards warfare and conflict, learning how to apply their powers to battlefield situations so they can operate as equal parts living weapon, psychic bodyguards and specialist advisors. Different Covens Militant specialise in different aspects of this, using Diviners as prophetic tacticians, Pyromancers and Telekines as weapons against the enemy, Telepaths to oversee the men (grudgingly serving alongside the agents of the Commissariat in this role) and interrogate captives, and Biomancers as warrior-mystics and medics alike.
When an armed force - be it the Adeptus Arbites, the Departmento Munitorum, local PDFs, local security/law enforcement, or some parts of the Inquisition - requests the assistance of the Scholastica Psykana Calixis, all the psykers dispatched will be of a single Coven network in order to continue limiting the potential spread of external corruption. In such cases, a single Psyker will oversee the entire Psyker contingent of the force, and all those under his authority will be selected from Covens already beneath him. For example, a force requesting aid from a Lieutenant Savant will mean that the Lt-Savant himself, and many of the the Savants Warrant and Savants Militant beneath his authority as a Coven Leader will accompany him to the warzone, serving under his authority in battle.
The Covens Scholastic
The other major branch of the Scholastica Psykana Calixis are the Covens Scholastic, who tend as a rule, to be more concerned with ephemeral matters than the more pragmatic and militarised Covens Militant. In the broadest sense, Scholastic Psykers are more potent than their Militant equivalents, having more time to focus on studying and mastering their power.
Scholastic Psykers - starting with the lowly Scholars Materium - tend at one end of the scale to operate in isolation from their peers a lot more than Militant Psykers, operating as lone advisors, court psykers and similar, but tend also to maintain more regular long-distance contact with the rest of their Coven, due to easier access to Astropaths (Savants Militant are rarely permitted to use Astropaths in times of warfare, simply because they're such an important commodity when they are available, that only high priority messages are allowed).
Where Covens Militant are more like a military unit in structure and nature, Covens Scholastic are more akin to study groups, often with several Psykers working on the same subject and the same project, even if spread across several worlds.
Between Sanctioning and Coven Initiation
Many Psykers are not yet full members and operatives of the Scholastica Psykana, having only recently returned from their Sanctioning on Terra. These Psykers do not yet exist as part of the Coven system, having not fully demonstrated their worth, inclinations or preferences. Instead, they're assigned to a single Psyker from amongst the Covens (normally one specially-briefed for the task), who will oversee their initial training, and the Sanctionite will be assigned to one or more postings to gain some practical experience under the auspices of a superior, serving as an apprentice (or Neonate, to use the Scholastica Psykana term). This continues for some time, until the Neonate is deemed ready to progress further, where he will submit his request to be entered into a Coven.
These Aspirants may be given further assignments to test their skills and their loyalty, but with more autonomy than they had as Sanctionites or Neonates, as the tests are for them alone. Should they succeed in convincing their betters that they are worthy of elevation, they will be assigned to an appropriate Coven and allowed to go about their business as fully-fledged Psykers.
A short time later, I elaborated on a few related ideas, in a second post, copied below:
The Coven system I've suggested is designed to be largely self-regulating; that is, each Cell polices itself and the ones directly below it, both because corruption is dangerous to psykers in general, and because a psyker will be punished for the misdeeds of those lesser psykers he is responsible for.
External policing comes at the highest level, something I didn't touch on in my previous post.
Essentially, the rank structure within the Covens Militant and Scholastic mirror those already present in the rules - Militant Psykers advance from Savant Militant, to Savant Warrant, to Lieutenant-Savant, to Savant-Adjunct, to Preceptor-Savant, for example, just as PC Imperial Psykers of that specialisation will.
However, there is one step above that for both paths. For the Covens Militant, each network of Covens will be led by a single Savant-Commander, while each network of Covens Scholastic will be led by a Scholar Ephemeral (both are working titles, stand-ins that can easily be replaced if a better idea is suggested). These highest-ranking Sanctioned Psykers (my estimates suggest ten such beings - a Savant-Commander and a Scholar Ephemeral for each Discipline of psychic powers) form a Sector-level council (remembering that these notes cover, primarily, the Calixis Sector).
This council elects one of its number to serve as the Scholastica Psykana's voice in the Lord Calixis' court. He also deals closely with the Astropathic Network and League of Blackships operations within the Sector and thus represents the Adeptus Astra Telepathica's interests as a whole. To the outside world, the council is a non-entity - the council has no external powers, save those they collectively bestow upon their 'first-amongst-equals'.
This council has vast internal powers, however - it oversees the training, deployment and operations of every Primary Psyker in the Sector (my notes estimate roughly two and a half million Primary Psykers in the Calixis Sector, based on 10 Coven Networks, each five levels 'deep' with an average of 13 psykers per level). As such, it is heavily monitored by external agencies.
Three beings (neatly bringing the council to 13 members) oversee and pass external judgement over the council's meetings. The first is a high-ranking member of the Ecclesiarchy, appointed by the Sector's Cardinal - representing matters spiritual. The second is a high-ranking Arbites Marshal - representing the rule of the Emperor's Law. The third is an Inquisitor (any Inquisitor, in theory, though tradition dictates a psyker is preferred, as they best understand the risks and responsibilities of the Scholastica Psykana), representing the Emperor's Will. Three beings deemed eminently qualified to judge the purity and loyalty of the sector's psykers.
Beyond that, as with all branches of the Adeptus Astra Telepathica, the Scholastica Psykana is open to full and regular Inquisitorial inspection, a process little different from the common tradition of Inquisitors volunteering to spend a period of time overseeing the operation of one of the Blackships.