Imperial Knights - Questor Mechanicus: House Taranis - The first of the knightly houses to be established was that of House Taranis. This truly ancient house predates any other by many hundreds of standard years, for it was first founded on Mars during the Age of Terra. As the industries of the Red Planet developed into a vast metropolis of advanced technological mastery, so too did it evolve to become the first and foremost of the Forge Worlds, and the Knights of House Taranis were its guardians. The STC technology supplied to many of the expeditionary fleets during Mankind's first expansion across the stars included designs for armoured suits of exo-armour based on those first developed to be used by the Knights of Taranis. When the Knight Worlds were first rediscovered during the Imperium's Great Crusade many thousands of years later, it is likely that the ancient Mechanicum used their intimate knowledge of the Knight suits worn by House Taranis to help win the loyalty of those worlds.House Krast - The Knight World of Chrysis was the first to be rediscovered at the outset of the Great Crusade by Rogue Trader Militant Jeffers. Its proximity to Mars meant that the knightly houses of Chrysis were able to swiftly resupply their Knights with new weapons and equipment. Foremost amongst these knightly houses was Krast, and their strength at arms was bolstered further still by their new alliance with the ancient Mechanicum. Gladly did the full might of House Krast set forth at the bidding of Mars to fight in the Emperor's wars, leaving the lesser houses to consolidate the alliance with the Mechanicum on Chrysis. However, the Knight World's proximity to Mars was to ultimately prove its undoing when the full might of Horus' Traitor forces descended upon Chrysis as he carved a bloody path across the galaxy towards Terra. The Knights of House Krast returned to their planet only to find it devastated and its lesser houses all but erased from existence. Ever since the Horus Heresy, the Knights of House Krast have vowed that whenever the threat of Chaos rears its malformed head, they will be there to sever it at the neck.House Raven - Of all the knightly houses in the Imperium, House Raven is the largest by far. Indeed, Raven's Knights number in the hundreds, with dozens of households ready to answer the summons of the Adeptus Mechanicus should they be called to war. Quite why there are so many Knight suits available to House Raven is something of a mystery. However, ancient records dating back to when their world, Kolossi, was first settled refer to a piece of STC archeotech that long ago fell into disrepair and was lost. Whether this STC system and Kolossi's natural resources served as the perfect combination for producing Knight suits, or if the first Human settlers merely prioritised the creation of Knight suits above all else, remains an enigma. House Raven first allied itself with the nearby Forge World of Metalica during the Great Crusade in the late 30th Millennium. Lord Gregor Raven, House Raven's ruler at that time, struck a deal with the tech-adepts of Metalica to ensure that his house would have sufficient Sacristans to service his full host of Knights. In return, Gregor swore eternal fealty to the ancient Mechanicum of Metalica -- a pact that remains to this day with the Adeptus Mechanicus faction of that Forge World.