Known originally as the Spectral Flames before contact was made with their parent chapter, were among the countless many chapters created in the wake of Guilliman's Indomitus Crusade, formed from the ranks of the Unnumbered Sons of Vulkan. The Astartes that would become the Ghosts of Nocturne had been assigned to Crusade Fleet Tertius' Battlegroup Lamdax, under the command of Raptors 8th Captain Aremis Koryn. Under his stern and watchful gaze, the Astartes that would eventually form the Ghosts of Nocturne learned to use the shadows as a weapon, one as deadly as any bolt or blade. Additionally, Koryns' experience as 8th Captain and unorthodox sense of combat pragmaticism meant that those under his tutelage were also expertly trained in unarmed fighting in extremely close quarters. By the time they were given leave to strike out on their own, the newly minted chapter would become masters of stealth, guerrilla warfare and hand-to-hand combat.

As the crusade progressed, the future members of the chapter gained great renown from other members of the fleet and the human populations they encountered. Indeed, beyond simply being lauded for their skill at arms or fierceness in battle, the proto-Ghosts of Nocturne gained a reputation for their stalwart defense of the human populations of the worlds they liberated, taking every precaution to ensure that the Imperium's citizens were spared, even at great personal cost themselves. They were also found to be honorable, humble and amicable warriors by those who fought alongside them, whether it be fellow Astartes, Astra Militarum regiments or Adepta Sororitas. No matter the ally, the Ghosts of Nocturne were ready to stand fast and fight to protect the Imperium and all those who lived under its banner.

Some found their appearance and their tactics strange given their genetic legacy, but the Ghosts of Nocturne were nevertheless skilled in their craft and successful in their pursuits. However, their genetic links to the Salamanders and to Vulkan himself would not be denied fully, The Ghosts of Nocturne discovered their fascination with fire quite early, finding that they were instinctively drawn to it. They found that flame could not hurt them or burn their forms, and instead filled them with warmth and an odd yet calming sense of serenity and calm when fire covered their bodies. This interest would slowly develop into great reverence and would eventually help form the basis of the Ghosts of Nocturne's most important rituals and traditions.

When the time came, the Vulkan-descended Greyshields of Battlegroup Lamdax were christened the Spectral Flames, given a modest but formidable fleet to call their own and assigned to protect the fledgling Imperial worlds of the Hellas Sector within the Segmentum Pacificus, an assignment they accepted with grace and enthusiasm.