Raven Guard - Under the Raven's Banner: By the time the Raven Lord took command of his Legion, the Great Crusade was over a century old. Corax was quick to impose the style of war he had perfected on Lycaeus over that which had come to define the XIXth Legion, melding stealth and guile with vigilance and swiftness.It was during these early years that much of the native demeanour of the old XIXth Legion, particularly the more cold-blooded ways of the Xeric tribes, was purged. The Legion had so often served in oppression, repression and occupation forces that Corax saw in some of the Terrans of his XIXth Legion something akin to the slavers of Lycaeus.Several of the Legion's highest-ranking officers were displaced or reassigned to non-command roles, including Lord Arkhas Fal, who had commanded the XIXth Legion as its Master for three decades before the coming of the Raven Lord.Under the Primarch's guidance, distilled into a series of battle-mantras, the Raven Guard developed their skills to preternatural levels. Corax is even known to have bested Roboute Guilliman in his brother-Primarch's notoriously testing strategio-simulcra, making use of several unconventional troop types his brother-Primarch had never before faced, including the forerunners of the Moritat.Corax only bested his brother three times in this manner, and once the master of the Ultramarines heeded the lesson and adjusted his tactics, the Raven Lord would never beat him again.During its restructuring, the XIXth Legion commissioned several innovations from the forges of Mars, all of them cunningly wrought to further its mastery in the arts of stealth and speed. As the Thunderhawk gunship entered widespread service, the Raven Guard secured for themselves a variant known as the Shadowhawk, sporting all manner of technologies that made it invisible to all but the most sensitive of Augurs.In addition, the Legion gained access to the Whispercutter, an open airframe flyer constructed about a gravitic impellor and capable of dropping ten Legionaries into a war zone in utter silence and with practically no chance of detection. Such technology was created not by the Martian Mechanicum nor any of the Forge Worlds, but by those master artificers of Kiavahr who formerly served the tech guilds.Utilising strands of machine canon unknown to the mainstream of the Mechanicum, the Kiavahran guild artificers created all manner of systems at the behest of the Raven Guard and in time the Legion's Techmarines were inducted into these mysteries, although it has been speculated that the Kiavahrans might have been declared outcast by the jealous lords of Mars, were it not for the patronage of so august a body as the Legiones Astartes and the Primarch Corax.As the Great Crusade ground ever onwards, Kiavahr assumed its position in the Emperor's Imperium of worlds. While its output was not equal to that of a fully-fledged Forge World of the Mechanicum, with the aid of the Tech-priests of Mars, its forges and manufactoria produced and exported vast quantities of materiel as well as a number of the more specialised machines and weapons required by the Raven Guard Legion.The guild artificers attempted to retain their closest secrets from the Mechanicum with some small measure of success, and clung on to their independence from Mars. Having remained self-sufficient throughout the lonely dark ages, Kiavahr remained unwilling to cede its secrets to outsiders, the only authority it recognised being that of the Raven Guard.Of all of the Mechanicum's subsidiary domains, Kiavahr maintained relations with only one -- Gryphonne IV. The terms of this relationship remain unclear, but because the Legio Gryphonicus fought alongside the Raven Guard throughout several of its larger scale campaigns, it can be assumed that some manner of reciprocal pact was, and perhaps still remains, in place.