Trajan was a Captain in the Ultramarines Chapter, who came to the aid of Salamantis VI, when the Chaos Space Hulk Blasphemous Voyager existed the Warp and began to drift towards the Shrine World. When he arrived with his strikeforce, they realized the Space Hulk was too massive for their ships to destroy it and so a new plan of attack was created. As the Blasphemous Voyager drifted closer to the Shrine World, the Ultramarines quickly began boarding actions upon the Space Hulk; with Trajan personally leading his Battle Brothers in planting well placed explosives within it. Despite facing a fierce resistance from the Chaos Space Marines aboard the Space Hulk, the Ultramarines were successful and as the explosives' timers began to countdown, the survivors retreated to their extraction points. Captain Trajan's squadron however, was cut off by the attacking Chaos Space Marines and was not able to escape in time before the explosives went off.
In the aftermath of the explosions, Trajan was left severely wounded and was the only survivor of his squadron. He was soon captured by the Chaos Space Marines and brought before their Chaos Lord, who commanded the Blasphemous Voyager. The Chaos Lord mocked Trajan for failing in his mission and told him the Ultramarines' ships were already retreating in disgrace. With the minimal damage the Ultramarines' explosives had done to the Space Hulk, the Chaos Lord exclaimed there was now nothing to stop them from destroying Salamantis VI. When the Chaos Lord had finished, Trajan simply laughed and told him, their mission was a success. The Ultramarines had never intended to destroy the Space Hulk with the explosives - they had just needed to alter its path away from the Shrine World and into an unstoppable collision course with its sun.