Editing Horus Heresy (section)

===Rogal Dorn: The Emperor's Crusader===

Fafnir Rann and Sigismund are standing around on the walls of the Imperial Palace just before the Siege, wondering why their primarch got the job of fortifying Terra, when Malcador pops out and reminds them of the Night Crusade, whereupon all three of them start reminiscing about it.

Six decades into the Great Crusade, ten years after Dorn was recovered and shortly after Lion el'Jonson was found, Dorn, Fulgrim, Horus, and the Lion are ordered to deploy into the Occluda Noctis, an area of the galaxy obscured by a major Warp storm. Their goal is to bring the area into Imperial compliance and find the source of an unknown threat that’s already destroyed multiple expeditionary fleets. All four of them have their own ideas about how best to prosecute the campaign; the Lion wants to work his way in from the periphery of the Occluda, while Dorn’s plan boils down to “drive my fleet into the heart of the Occluda and get shit done”. He and the Lion disagree about who’s right to the point where Horus and Fulgrim have to try and calm them down, but Dorn insults the Lion, who demands an honor duel. The Lion’s champion wins because Dorn forgot he had Sigismund, and Rogal immediately apologizes to his brother for insulting him. Ultimately, they agree to do both plans. Dorn’s works surprisingly well, though the Fists don’t rack up nearly as many compliances as the Dark Angels and Emperor’s Children since he's insisting on a diplomatic approach and the fleet has to be careful when making Warp jumps in the Occluda. They eventually encounter the unknown enemy, which turns out to be a lost human civilization called the Kapikulu Continuum that uses cloaking tech and special warp gates to get around, requiring Dorn to up his game to counter them. He manages to outsmart and defeat the Continuum's fleet and convinces its leaders to join the Imperium. At the peace negotiations, he learns that the Continuum used to be the slaves of a xenos race that altered their brains to grow a special neural web that lets them use all their nifty technology (and also makes their heads explode if a psyker tries mind-probing them), which means that they’re not technically human anymore. Dorn concludes that he can’t risk letting them join the Imperium and orders them to be wiped out, following the exact letter of the Emperor’s orders: “Remove this hidden threat.” He is genuinely distressed by this outcome, but sucks it up and moves on.

The whole point of the story turns out to be summing up Dorn’s character: he was made the Praetorian of Terra because he can be trusted to do exactly what he is told to do, fulfilling both the word and spirit of the Emperor’s commands, and there’s no one else the Emperor would rather have guarding his capital world. Also a funny sidenote: Perturabo is found during the course of the Night Crusade and Dorn sends him a friendly welcome message, which one character declares will certainly lead to a greater fraternal bond between them in future.