Yu'Vath - Crusade's Triumph: To this day, it remains unclear just how many of the Yu'Vath were active within the region when the crusade arrived. The wretched species had attained a high level of decadence as they ruled over their servant races from their blasphemous towers and installations.Reports suggest that every Yu'Vath may have had in excess of a million slaves bound to see to its every need, and some of the corrupt beings clearly had entire worlds devoted to fulfilling their every whim.Their urges were as diverse as their imaginations, but almost all involved harnessing the unstable nature of the Warp to incur perversion on a planetary scale.Reports of their physiology and psychology are fragmentary. Inquisitorial edicts certainly eradicated some of these records, while others were lost to the vagaries of time and the eccentricities of local archival systems.There are no extant reports indicating that any of these wretched xenos were captured alive. There are numerous references to reports compiled by members of the Adeptus Mechanicus Magos Biologis, but none of the actual analyses are known to have survived intact.Fragmentary records indicate that at least three autopsies were performed, but the available data is remarkably inconsistent and uninformative. It may be that none of these studies had access to a complete Yu'Vath corpse or it could be that the available samples were markedly divergent in their anatomy.It is clear that the combination of Warp influence and their advanced technology resulted in significant degrees of morphological variance between members of the species. If the available data is any indication, then the Yu'Vath were not necessarily humanoid in structure, but this may have been a direct result of extensive bodily modifications or accidental mutations.Some members of the Ordo Xenos suspect that the Yu'Vath culture may have been in decline prior to the arrival of humanity in the region. It could be that the ancient race had achieved such a height of decadence that they were no longer capable of sustaining it, even with the assistance of the alien races they had enslaved.A few members of the Magos Biologis have even gone so far as to suggest that the common genetic markers shared by their client races might actually indicate a commonality of origin. If this were true, then those species might actually be the synthetically engineered descendants of the Yu'Vath rather than unique xenos in their own right.This logical path begins with the notion that the Yu'Vath must have had a total population that was immeasurably large in order to have established colonies upon so many worlds within the Expanse. However, when the Angevin Crusade overcame their war machines, the number of opposition forces was modest at best. It might also suggest that somewhere beyond the explored reaches of the galaxy, a massive Yu'Vath civilisation yet remains.Given their abilities to manipulate the energies of the Warp, they might even have developed facilities within the daemonic realms beyond the borders of reality. If such survivors remain, they might lie in wait to re-establish their empire at the expense of any humans who dare to stand in their path.The countless Yu'Vath ruins spread throughout the Koronus Expanse also cause concern. The vast majority of these are little more than broken cities buried beneath tonnes of rubble, characterised in part by the Yu'Vath's architectural preferences. While the styles varied substantially, most of their buildings were constructed of raw stone, crystal, or bonelike ceramics. In the majority of cases, these structures were encapsulated with complex polymeric layers that preserved the construction and may have also played a decorative role.In many instances, these unusual coatings were applied to the structures such that they inscribed complex geometric structures, arcane formulae, or complex and blasphemous pictographs of inhuman iconography. Further, many of these structures seem capable of some degree of self-repair, a feature that makes dating their origins extremely challenging.The iconography of these sites represents another common reference point to identify their origins. The symbols inscribed are often uneven and asymmetric in their style. Though no known literature has survived the passing of the species, many of their ancient devices also bear such iconography. Rumours suggest that some agents among the Ordo Xenos may be capable of translating these ancient markings. However, the rumours also hold that any who attempt such a translation could lose all semblance of sanity in the process of deciphering the hideous glyphs.The overall preservation of the complexes varies substantially between various sites and planets. In some instances the structures often seem habitable, while others are little more than buried rubble. The inconsistencies between various discoveries also pose their own mysteries. In some star systems with multiple habitable worlds, only a single planet shows signs of Yu'Vath inhabitation. In others, Yu'Vath structures are densely packed upon airless rocks too small to ever have maintained an atmosphere.Due to the unusual technology, dating their creation by traditional methods is seldom accurate. Fortunately, in some cases, the surrounding rock and soil offer a better clue to their age than the basic structures. Of course, this is only true for the oldest of structures, where the underlying planetary elements have shifted due to the passage of time that can only be measured in a geological sense. For those sites that were active up until the arrival of the Angevin Crusade, such reference points are far less common.