Below is a WIP background inspired by a model I picked up on ebay some time ago. Comments and criticism are very welcome; I'm intending to put this on to the Carthax wiki once it's a little more polished. Thanks for reading!
The Ixine Utility Breed was discovered by the rogue trader, Oscan Cospericus in the 2nd century of M37. It is a primitive bipedal species found upon a handful of worlds in proximal star systems, apparently the residual organism of a real-space capable civilisation of unknown qualities.
Thus begins a rather dry accounting of this very minor xenos by a redacted Magos Genetor, which came to light only 27 years ago. Cospericus' personal log is more compelling fare, describing craggy worlds populated by tribes of hunched and brutish xenos. Therein he makes claim to have established very basic communication with one clan of Ee'ub, as Cospericus says they name themselves. He writes of monumental ruins in rad-blasted wastelands, half-obliterated stone friezes and escaping certain death at the claws of enormous bestial strains of Ee'ub.
What the good captain does not overburden us with is facts. Beyond chart co-ordinates and uninspiring assayor reports, we are left with no hard data all else appears to have been lost. Most frustratingly, it is Cospericus who first coins the term Ixine Utility Breed and names their creators the Ixians. And yet whereby he came upon these names is never explained nor even hinted at.
The nameless Magos then is our only source of facts but also brings a troublesome matter to our Ordo. The true horror of this xenos race is that the IUB are in fact of human stock. The Magos reports a helical correlation of 99.813% with acceptable Imperial norms and concludes that the discrepancy is a result of intelligent modification.
Uncharacteristically of the Cult Mechanicus, the Magos goes on to extrapolate from Cospericus' written accounts and no less than three pict-captures, none of which can thus far be traced. They hypothesise that the Ixian culture was possessed of advanced fleshwright technologies and bred an unknown number of task-specialised organic stock. With reference to a particular pict-capture of a defaced frieze, the Magos even extends themself to positing a slave uprising that resulted in the collapse of Ixian civilisation and the present state of the IUB as cave-dwelling primitives.
It is my humble opinion that this speculative work is the reason for the Magos' name having been expunged.
Not all of what Cospericus tells us is upheld by the Magos' report however. Of particular note is the matter of communication. The Magos finds no platform for meaningful two-way communication in the clicks and glottals that appears to pass for speech among living specimens. The structure of IUB oral apparatus makes it impossible for the species to even mimic human speech and the conclusion is that Cospericus was deluded in his belief that he was communicating meaningfully. That said, the Magos does allow that the sample showed limited potential to comprehend simple directions given in Low Gothic.
The Magos makes no comment as to the extend of this comprehension but anecdotal evidence from later contacts suggests varying capacities ranging from that of a canid, to something approaching ogryn levels of intellect. The agri-world of Verdandi Principle is the only instance of the Ixine Utility Breed occupying a planet of interest to the Imperium. Guardsmen of the Namoan XVII cleansed the world early in M40 and after action reports from the latter stages of pacification indicate that the IUB had learned to fear the armaments of sentinel walkers. There are numerous accounts of skilled pilots herding xenos like grox and more interestingly, many more of careless patrols being ambushed and their sentinel support being targeted first.
Otherwise the Ixine Utility Breed are all but absent from Imperial annals. I can in point of fact find only two instances across the entire segmentum. The most recent is of an IUB gladiator on Colossus III and dates back 5 years whether this individual still lives is presently unclear.
Of much greater interest is the first instance however. Nineteen standard years ago, following the inconclusive caucus which discussed the aforementioned Magos' report, Inquisitor Haus Ottofar utilised a pair of IUB to support his infiltration of a smuggling network. Called the Aspican Trail, it dealt in numerous inconsequential narcotics but its primary purpose was the illicit transportation of political recidivists to a habitable moon within an uncharted star system. The presence of two 'xenos' in his crew accelerated Ottofar's chartist captain persona into a position of trust in the Aspican Trail and was so convincing that the Inquisitor was detained by his allies within the Imperial authorities when the Trail was crushed. Ottofar, an exponent of the Amalathian philosophy, spent seven years on trial for heresy and moral corruption on Bosartes Caligula before Governor Antiges apparently accepted the evidence of our unnamed Magos Genetor. Meanwhile Ottofar's Ixine survived the Aspican Purge, only to be sentenced to trial by ordeal in a rural canidrome, the affair broadcast planet-wide. Sources were difficult to find but I gather that two Kennel Lords were bankrupted in the course of the trial and a third has not been seen since being invited to a dinner at the Lord Governor's palace.
As briefly mentioned above, the classification of the Ixine Utility Breed is an uncertain matter. The official designation remains Xenos Minoris and the species has not presented an obstacle to the Imperial Will since Verdandi Principle. Equally they hold little import as a stable strain of abhuman, being of little use to the Imperial Guard, and I find little interest among our Ordo to revisit the matter. The first caucus failed to reach a conclusive verdict on the IUB due to the unknown nature of their Ixian creators. If these fleshwrights were indeed a race of genuinely xenos domitors then the Ixine Utility Breed are no doubt corrupted beyond redemption. But the possibility exists that the Ixians were also human stock and Oscan Cospericus overlooked an interstellar ancestral civilisation that may have flourished in isolation during the Great Crusade or even Long Night.
While the latter is outside the common purpose of our Ordo's membership, it presents an intriguing potentiality that I would humbly exhort the Hallowed Orders to investigate as resources allow.
Your obedient servant,