Stuck in my head-Jurgen the Custodes:
Most Honored, Revered, Respected and Worthy Captain-General Trajann Valoris, receive this report from this humble warrior, serving as one of the Eyes of the Emperor in that most miniscule of lesser regions known as the Damocles gulf, far from the resplendent glory of His presence and the glory that is Terra.
I have attached myself to a feeble Astra Militarum artillery regiment, consisting of less than ten thousand mortal souls and a handful of batteries of the foolishly named Earthshakers (for as all know, only the Emperor, or the great guns of the Adeptus Custodes can truly shake the ground). I did this because the elder Eyes of the Emperor advised against joining any line regiment, for fear that my strength would reveal that I am no mere mortal, but one of the Emperor's created companions, as far above them as the Emperor is above his sons. And indeed, this wisdom has proven true. My keen hearing has heard many of the soldiers discussing my appearance and strength, but they are quickly hushed by their fellows as they simply view me as a strong mortal. If we were to face some enemy in close combat, I fear (obviously only in the colloquial sense as fear is not a vice the Emperor left in our makeup) that I might be revealed as I defeated the Emperor's enemies all too quickly.
Indeed, I was concerned such might have occurred in the instance I am about to relate to you, Most Skilled, Gracious, Graceful, and Earnest Captain General Trajann Valoris. But of course, I was able to overcome and maintain my disguise, for I am one of the Adepta Custodes! On the mining world of Desolatia (which produces minerals and resources needed to craft the weak weapons which the Astra Militarum can be trusted to wield and are capable of carrying) the regimental commissar suffered a terrible accident where he fell off an artillery piece he was examining, onto an array of bayonets laid out for inspection. Truly a terrible loss for the regiment and the Imperium, as I overheard many of the mortal soldiers talking about 'what a shame it was' that he'd died. I was deeply concerned that their morale might collapse, as you know how mortal soldiers are, but I was pleased to hear that the Officio Prefectus had acted with commendable speed (for a mortal organization) and assigned a new commissar.
The regimental commander lost no time in assigning me to assist him, clearly recognizing, despite my brilliant disguise, that I was the most able to ensure the survival and success of this critical member of the regiment's leadership. Of course, the commissar himself was nearly struck dumb at the honor being conveyed upon him, to be guarded and aided by one the of the Emperor's Custodes (though of course, he did not realize it). At first, I though the man a fool, but the sudden arrival of servants of the Great Devourer revealed the truth of the man. He has a brilliant and cunning tactical mind, realizing that the terrible Tyrannids would be preparing a flanking attack upon our fortified position and he has a stout heart, leading the reconnaissance to confirm that in person. But, most impressively of all, when our vehicle was wrecked and I sent him back to the firebase alone while I faced down the swarm (eviscerating a Hive Tyrant as I did so) he chose instead to stand alongside me and fight them back. Together we slew our way back to the firebase even as the artillery burst behind us, shattering the Great Devourer's attack.
Fortunately, we were too far from the firebase for any of the others to see us engage in battle and the commissar was too busy engaging in his own battles to notice my victories and prowess, so my cover remains intact.
I write to say that, having spoken to the mortal, I think his mind is far too sharp, his will is far too sturdy and his courage is far too undeniable for him to remain in such a lowly position. We must push this Commissar Ciaphas Cain into a position where his talents can more directly serve the Emperor and Imperium. He is far too humble to recognize it, but he is exactly what this sector needs in order to get itself into order.
I trust you can speak with the appropriate parties to arrange his elevation. I will, of course, accompany him, in my brilliant disguise as his aide.