++ Chamber Borealis ++

I will be the first to admit that I have little by way of a frame of reference since I have spent precious little time around anyone with psychic abilities before, but being in the presence of a Quæsitor is an unsettling experience to say the least. Indeed, one could write much upon the subject of mankind's abject fear of and utter reliance upon the psychic members of our species, but I shall refrain from such digression here.

I am given to understand that the majority of orthodox Astartes chapters maintain a Librarius. There are of course exceptions to this, perhaps the most notable being the Templarum Ater, who I am assured reserve nothing but hatred towards those with even the barest hint of psychic talents. Within those chapters possessed of them though, in addition to such mundane tasks as record keeping and counselling their war leaders, the Librarius maintains oversight of the wellbeing and training of the battle-witches of the Adeptus Astartes. 

While the intricacies of the rituals and teachings that are their stock in trade are far beyond my comprehension, I believe that the origins of the Librarius lie within the Magna Crucis, though it was censured and disbanded by the Master of Mankind before it took root in all of the Legiones and was ultimately only resurrected in desperation as conventional warriors found they were all but powerless to combat the warpcraft wielded by those gathered to the banner of The Serpent. 

I believe that much of the garb of the Librarius emerged in this tumultuous time as well.  Indeed, Æplogestes's Admonitio Historiæ Imperialis suggests that the distinctive Psionic Hoods worn by members of the Librarius were derived in part from technoarcana recovered from the ruins of pre-Imperial cultures by the Mundi Comedentii and Manus Ferreae which took the form of collars of blackened silicate that, at great cost would allow the wearer to quiet the Immaterium, though I have been unable to fully corroborate this assertion.

If [REDACTED] is to believed, and I find I have no reason to doubt the veracity of his statements, then while they may appear similar in function and form to their Imperial counterparts, the origins of the abilities and armaments of the Quæsitors lie far earlier in the history of mankind, being instead derived from lessons hard won by a handful of Astartes with latent psionic abilities out among the Halo Stars. I believe that the Astartes do not feel fear, but what horrors must they have endured alone the darkness while attempting to gain understanding and mastery of their abilities? 

As comfortable as I was to eventually become among the majority the subjects of my rememberance, I remained unable to be entirely at ease with [REDACTED]. Merely being in his presence was unnerving enough as I have said, but when he revealed to me the power that Quæsitors possess in the disciplines such as divination, telepathy, fulmination and geomancy, a fear I could never entirely quiet remained ever present in my thoughts. To earn the ire of an Astartes would be terrible enough, but to anger one possessed of the ability to conjure fire from thin air, shatter the very earth itself or still hearts with but a thought would be so very much worse...

Illiatariu. C., Rememberancier Documantist Minoris. To Walk Among Demigods. A Treatise Upon The Nature of The Argyntum Stellae., Published 863.M33, Sector Heliopolis, Segmentum Pacificus.