Alright, first things first, let's get a few things off the bat.
One, the Warhammer 40k universe, along with a few quotes in the prologue of this story, are owned by GW, and I, in no way shape or form, lay claim to it. Thank you GW, for your tricky No-Tolerance policies. Arknights is owned by Hypergryph and published by Yostar Games, love you two, keep it up. Phew, got that out of the way, let's move on to some minor stuff.
So, hey, it's me, Roseblade here. Somewhat new to story crafting, but definitely not new to fanfics. Been lurking around here for a while and I'm deciding to make my own spin on things. This story is... gonna be strange, in a few ways, but eh, I'll just place that under fanfic territory with writing. Additionally, feel free to criticize—even harshly—so long as there is reasoning behind it. I'll also be updating this when I want, though feel free to ping me if I haven't done so in a while, let's say 6 months. Last but not least, prologue is skippable if you know about any of the two universes and a little wordy, but if you don't mind, go right ahead. Alright, enough chatting, let's get back to why you're here.
Prologue: Universal Boundaries
In the grim darkness of the 41st millennium, there is only war… war so vile and detestable that hundreds of the quadrillion souls in the galaxy spend their short, meaningless lives fighting endless battles. Desperation roams the galaxy in swaths, snuffing out the joy for many as mercy became a rare commodity, shelved for eternity, and forgotten to time immemorial. Even in death, souls are not given the rest they so valiantly deserve, for the gods themselves devour them for their own ill desires. Few would be lucky to experience only the nightmares of what they would see, and not the entities that are real, hiding in the void, waiting to satisfy their thirst for carnage. There is no rest for the wicked or the peaceful, only the tireless charade of destruction, death, and despair. Reality itself is shredding apart by the very seams due to the plans of the Ruinous Powers, greedily ripping apart the galaxy in their wake.
Humanity, once glorious under the Emperor of Mankind's light, now dwindles as he sits upon his throne. He refuses to die and sink Holy Terra into the warp, and lives only by a sliver from the thousands of souls sacrificed to him daily. His undying corpse remains a beacon to mankind, powering the Astronomican by his will alone, yet it is all he can muster. What is left of the empire of man is but a fraction of its majesty, as the Imperium is fractured and left bleeding, being devoured alive by the scornful and besieged on all sides by the foul. Mere mortal men die by the trillions to keep the Imperium of Mankind from falling into the ashes of a forgotten empire.
Despite all this, hope remains alive, for the Primarch—one of the Emperor's sons—Roboute Guilliman, has awoken from his dreamless slumber by mysterious arcane powers and technological innovations. He has returned to Holy Terra, determined and resolved to set right this dire imbalance of fate, to defeat Chaos once and for all, and to restart the Emperor's grand plan for humanity. The Imperium, now on the cusp of recovery to its former glory, stands ready and willing to fight to its dying breath. Failure means extinction, death leads to suffering, and the only way out is through bloody, merciless, war. For the world of mankind now moves onto the next era, Indomitus.
In another galaxy, however, this story has never unfolded and will never unfold, for the intergalactic playground is a wide place, and souls are but a miniscule light compared to the stars, no matter how grandiose or powerful they may become. In another galaxy, in a world coincidentally called Terra, humanity is alone and on the verge of an all out war against itself. A war, although much less brutal, is seemingly more unjustified. This version of humanity faces the threat of extinction by a great many enemies, the most of all, a plague of stone that is a two-handed sword. Originium, the bane of existence, threatens to claim any and all, living, dead, or inanimate. Yet it is simultaneously used to create everything, from the lights on the streets to the swords in many individuals' hands. Originium has become both a blessing and a curse on Terra. The quaking storms in Terra's sky thrusts spears of this stone into the earth, giving any that come into contact a chance of receiving an early death sentence, or as many dreadfully call it, Oripathy.
All the while, monsters, just as foul and obscene from the Imperium's perspective, exist. Demons in the north overtake the mind and corrupt the soul of any who brave the icy wilderness, with many brave and noble warriors staving off their invasion for the time being. Leviathans in the deep oceans of Terra lie in wait, letting the water slowly rise so that they may gain a foothold to devour and assimilate all to be one and the same. And horrors beneath the earth sit still, wanting to be uncovered so that they may commit untold catastrophes across the land. Moreover, many gods were hunted long ago in the past, and now, they sit complacent to humanity's struggle for survival, doing nothing as friction starts to ignite the sparks of war.
Fear has not taken its rightful seat in the hearts of mankind here, for they are ignorant to the extinction that is on the distant horizon. They are greedy, wanting to take and take, until nothing is left but empires of dirt. Each faction of humanity allies with themselves more than any other group, and discriminates against any who have been inflicted with Oripathy as they are Infected—tainted and no longer seen as human. One group remains determined to guide humanity into finding a cure, rising from the ashes, Rhodes Island, a pharmaceutical company with some measures of self-defense to enact this plan. The leader of which is a hopeful Cautus by the name of Amiya, leading the fight for the Infected, and being advised by a few powerful individuals who wish to free Terra from its plague.
Yet, we are not following the story of the Imperium's newfound leader, nor the story of Rhodes Island's efforts. We follow the story of a Rogue Trader of the Imperium, and his inexplicable disappearance into the warp, never to be seen again. The founder arose from the Navis Imperialis, as the dynasty of Decimbrus was a recently crafted one, only they were gathering renown and fame in rapid succession. More so through trading the beautifully crafted armaments of the Imperium to important locations, but the Battle for Port Wander from the clutches of the Ruinous Powers as well as decent exploration into the more undocumented places of the Koronus expanse cemented this reputation. His son, Faust van Decimbrus, had trained to take up the role of the Rogue Trader, exploring the galaxy on his own to learn more tricks for the trade.
And so, after several more years, the first of House Decimbrus, Faust van Decimbrus, gained his father's Warrant of Trade. How pitiful is he to have gone missing in the Koronus expanse, depriving House Decimbrus of its firstborn son. This is his story; out of the quadrillions of lives that fight, he alone is an anomaly to the Imperium in more ways than one. May he find mercy in whatever hell he has stumbled upon.