The Imperial Fists are one of the First Founding Chapters of the Space Marines and were originally the VII Legion of the Legiones Astartes raised by the Emperor Himself from across Terra during the Unification Wars.
Rogal Dorn, known as "The Vigilant," the "Praetorian of Terra" and the "Unyielding One," and to his gene-sons by the "wall-name" of "Defiance," was the Primarch of the Imperial Fists Space Marine Legion and one of the greatest heroes in the history of the Imperium of Man. A being of thunderous zeal and stone made manifest is how many described the Primarch of the VII Legion. He had a stern and naturally unsmiling face, topped with an unruly shock of short, bone-white hair. His zeal was the fire of a son who believed in his father's dream for the Imperium without reservation and without question.
If the Primarchs were the Emperor's nature split like white light through a prism's rays, as many Imperial scholars of the Imperial Court suggested, then from such a point of v iew, Rogal Dorn was the Emperor's implacable disciple in the pursuit of the cause given flesh; without compromise and in who loyalty and duty was as integral as blood and breath. It was perhaps for this reason, that even before the betrayal of Horus, the Emperor named Dorn the "Praetorian of Terra," and drew him to His side far away from the Warmaster and his newly-forged command. To some among his brother-Primarchs, this served only to distance him and his Legion further from them, and those among them who had seen the sins of hubris and obstinacy in Dorn's undoubted stubbornness and pride, saw this aggrandisement as a further cause for discord and disquiet.
"Primarch-Progenitor, to your glory and the glory of Him on Earth"
The Imperial Fists stand out from other Space Marine Chapters since they possess no fixed homeworld, although they are most frequently based on Terra. Instead, the Imperial Fists rely on their 10,000-year-old mobile space fortress, Phalanx, to serve as their fortress-monastery. They maintain recruitment-chapels on various worlds spread throughout the Imperium. Part of the Imperial Fists' duties during the Great Crusade were to function as the Emperor's "personal praetorians," accompanying Him everywhere.
The Imperial Fists were usually used to strike a decisive blow against the enemies He confronted during that time. The role of the Emperor's bodyguards since he was mortally wounded during the Horus Heresy and interred within the Golden Throne at the heart of the Imperial Palace on Terra has now been entirely taken over by the Adeptus Custodes. But the Emperor's ancient trust remains a potent honour for the Imperial Fists and their Successor Chapters in the present day. The Imperial Fists are the inheritors of the proud traditions of their Primarch Rogal Dorn, his name venerated by countless trillions across the Imperium. History does not clearly record the details of the world on which the infant Dorn was cast when the Primarchs were scattered to the corners of the galaxy. What is known is that he presented himself to the Emperor as the Great Crusade reached the Ice Hives of Inwit, offering one of the mightiest space-going vessels ever constructed during the Dark Age of Technology as a sign of his fealty.
The Emperor welcomed His long-lost son into the ranks of the Primarchs and granted him primacy over the Imperial Fists Legion. The Master of Mankind returned Dorn's vessel -- called Phalanx -- to the Primarch, and it became the base from which Dorn, and sometimes the Emperor Himself, commanded some of the most glorious campaigns of the Great Crusade.
The Imperial Fists are one of the most valiant of all Chapters, held as paragons of the principles set down in the Codex Astartes and exemplars of everything to which a Space Marine is heir. The Imperial Fists stand as the steadfast defenders of the Imperium and the Emperor's unwavering shield; for ten thousand standard years they have been the bulwark against which the armies of Traitors and aliens have shattered.
While Rogal Dorn is lost, Dorn's final moments were of courage and supreme sacrifice, and this example still drives the Imperial Fists onwards to fresh victories. Indeed, if the Imperial Fists have a fault, it is that they continue to strive when others would yield or withdraw. Such unquestioning steadfastness has rescued many a victory from the ashes of defeat, but only at a steep cost in lives.