Rogal Dorn - Post-Heresy: After the internment of the Emperor in the Golden Throne, Dorn was stricken with grief. He felt the Emperor's near-demise to be his fault and led his Legion on a crusade of penitence across the Imperium. He was summoned back to Terra when Roboute Guilliman, now the lord commander of the Imperium and Imperial Regent, announced the adoption of his Codex Astartes, turning the large Space Marine Legions into the much smaller, 1,000-warrior Space Marine Chapters.Dorn was initially outraged at this proposal, feeling that the Imperium blamed him (and rightly so, he thought) for the fall of his brother primarchs. However, realising what damage another internal conflict could do to the fragile peace of the Imperium, Dorn finally relented and agreed to the Second Founding. This was a dark period in Rogal Dorn's life; he believed he had both failed the Emperor and his Legion now faltered without the guiding light of the Master of Mankind.Dorn was shaken to the core, shocked that the Imperium no longer trusted him or his Legion and that now after the loss of the Emperor and the failure of the Great Crusade the brotherhood of the Imperial Fists Legion would be sundered as well. Without battle to focus them, the Imperial Fists hovered on the brink, unsure of their future, with Dorn despairing that he had not seen the Imperium changing while he hunted down the Traitors.Dorn, Leman Russ of the Space Wolves and Vulkan of the Salamanders all at first refused the dictates of the Codex, and the Imperium seemed poised to tear itself apart in civil war again. The Imperial Fists strike cruiser The Terrible Angel was even fired upon by the newborn Navis Imperialis for the Imperial Fists' supposed heresies against the Imperium's new order. It was at this time that the Iron Warriors issued a clear challenge that Dorn could not refuse by building an immense fortress and daring the Imperial Fists to attack it.Some controversy exists about the next event in Rogal Dorn's life. What is clear is that the Imperial Fists could not be as easily divided into Chapters as, for example, the Ultramarines could. The total commitment to the entire Legion was bred into each Imperial Fists Astartes and many did not wish to form their own Successor Chapters. Dorn found the answer to this problem in meditation through self-inflicted pain, using a device known as the Pain Glove.The pain-induced vision that the primarch had while using this device revealed that his Legion had to be redeemed in the eyes of the Emperor, and that the way to salvation was through pain and self-sacrifice. Dorn meditated for seven full solar days in the pain glove until he saw a vision of the Emperor. Dorn realised in that moment that the Emperor was not dead and gone and that He still watched over His sons and the Imperium from within the Golden Throne.Decreeing that the Imperial Fists would all metaphorically enter the pain glove as a Legion, and emerge as separate Chapters, symbolically reborn, Dorn led his die-hard warriors in an assault on the Iron Warriors' fortress. The "collective pain" needed to cleanse the Legion and break it into Chapters was decided by Dorn to be the siege of an Iron Warriors' fortress, the so-called "Iron Cage." The battle known as the Iron Cage has gone down in history as one of great tragedy and remorse for the Imperial Fists. For not only was it a disaster, it also signaled the end of the VIIth Legion as a united fighting force.