House Vornherr - Great Crusade: In time, strangers appeared at the verges of the Luhnborg System who were not intent upon the destruction, enslavement or consumption of its peoples; a flotilla of scout frigates under the command of the veteran and celebrated aristocrat-explorer Rogue Trader Militant Kohnwallis pressed cautiously in from the system's borders, the leading element of the 12th Expeditionary Fleet's pathfinder units illuminating the vast, stygian gulfs between spiral arms.Possessed of few spacecraft, none of which were capable of Warp travel and none a match for the Rogue Trader's flotilla, there was little House Vornherr could do to oppose its advance.A veteran of a hundred such contacts, Rogue Trader Militant Kohnwallis displayed the utmost tact in his opening vox-hail setting the rulers of House Vornherr at their ease so that by the time the Imperial delegation made planetfall at Luhnborg-IX before the gates of the household's ancient manse, it was clear that hostilities were largely out of the question.Soon thereafter Duke Khorvun Bhaevenwulf, lord of the House of Vornherr and grand master of its Knightly Order, and Rogue Trader Kohnwallis entered into talks. It quickly became clear that the two men shared many characteristics of temper and mien, and both were drawn from aristocratic bloodlines which shared certain trappings of the nobility of Ancient Terra, suggesting a common descent which provided the foundation of subsequent negotiations.Within a solar month, those talks were concluded and Duke Bhaevenwulf announced that his house would ascend to the Imperium. Luhnborg-IX would remain independent of the Mechanicum, to start out with at least, for its size and power made a pact with any Forge World largely unnecessary, and when the bulk of the 12th Expeditionary Fleet laid over at Luhnborg on its great voyage towards the southeastern galactic fringe, Vornherr took its place amongst the crusading hosts, leaving a cadre of veteran Knight-barons behind to defend its holdings and govern its people.Upon aligning itself to the Great Crusade, House Vornherr was present at and central to many of the 12th Expeditionary Fleet's greatest victories. Vornherr's Knights took part in the latter half of the 12th's Long March to Ultramar, where they confronted numerous xenos strains, several of which they knew of old and took immense satisfaction in scouring from the stars for all time.Others were long known to Mankind at large, in particular the barbarous Orks, whose monstrous engines of war the Knights of House Vornherr had confronted in battle on numerous occasions before Imperial contact and soon became increasingly adept at slaying. Other foes Humanity had never encountered before and never would again, indescribable alien horrors banished from existence by the deeds of House Vornherr.The greatest and most portentous battle the Knights of House Vornherr fought in would be the First Scouring of Jardingris. It was here on this grave-world, under the baleful light of its black sun, that the house first took to the field of battle under the overall command of the Primarch Roboute Guilliman as part of a combined force consisting of twelve full chapters of the Legiones Astartes Ultramarines, the might of the Legio Metallica, ten cohorts of the Solar Auxilia and scores of Excertus Imperialis line regiments, along with the Conquestor companies of Rogue Trader Kohnwallis.The war against the anti-Human revenant-organisms of Jardingris was a bitter one indeed, and by its end the necrogenic xenos strain had paid for its crime of existence with its utter extermination. The victory came at the cost of a dozen Titans and a hundred Knights, tens of thousands of casualties amongst the Human infantry and almost three thousand Astartes were slain; a truly phenomenal tally for a single planetary assault, but one not unexpected given the threat.At the height of the victory parade, carried out at the conclusion of the war amid the dust of that now-silent world, the duke of House Vornherr went down on one knee in his battle-scarred Cerastus Knight-Lancer before Guilliman's review stand, and his entire house echoed his act.In that moment, the duke pledged his house to fight alongside the hosts of the Five Hundred Worlds of Ultramar unto death, and although detachments of Vornherr would be committed to battle under other primarchs, in particular Magnus the Red in the gruelling jungle wars of Sophias-Mors and Rogal Dorn at the costly Delta-Arbuthnot Landings, the house would hold none in such high regard as the Lord of Ultramar.Thus when the Warmaster Horus ordered the Calth Conjunction at the Veridia System in preparation for war against the Orks of the Ghaslakh Xeno-hold, the Knights of House Vornherr were proud to answer.In the aftermath of the Triumph at Ullanor, which the house had received the honour of attending, House Vornherr had separated into numerous detachments assigned to war zones across the Imperium, and as the Ultramarines voyaged from the Sol System to Veridia, so the scattered elements of House Vornherr mustered at their home system of Luhnborg.There Duke Sorvak Bhaevenwulf, the heir of old Duke Khorvun, tasked some of his most trusted and experienced barons with guarding House Vornherr's ancient keep before leading the remainder of his force -- a formidable army of several hundred Knight armours and their supporting Sacristans -- to the muster at Calth.