Fimbrus was the Chief Apothecary of the XVIII Legion when it was led by Legion Master Cassian Vaughn during the Great Crusade[1a], and he took part in the XVIII's campaign to save the Imperial Systems of the Taras Division from an Ork invasion.
Despite their best efforts, though, the vastly outnumbered XVIII could not stop the advance of the over a million-strong Ork horde and could only slow the Xenos down long enough for the populations of invaded worlds to evacuate and escape into the void. They did this repeatedly, from one fallen System to another, until they reached[1b] the Taras System and Legion Master Vaughn told the XVIII they would retreat no further. As the Taras System was home to billions, Vaughn knew the Legion could not fight long enough to have the entire System evacuated. Instead the XVIII would draw the Orks to them, by deploying to the System's volcanic Death World Antaeum and use its destructive nature to break the Ork horde. With no chance of Imperial reinforcements, though, all within the XVIII knew this was to be the Legion's final stand[1c]. When the Orks finally invaded Antaeum, the XVIII made them pay for every step, but the Xenos' sheer numbers began to overwhelm the Legion. Soon Vaugh was seriously wounded in battle with an Ork Warboss and would have died, were it not for Fimbrus' medical skills. The Legion Master's wounds were so severe, however, that they both knew he was close to death. As the battle continued to rage, a new fleet appeared in the System[1a] and Vaughn ordered Fimbrus to do everything possible to keep him alive until they could determine the identity of the fleet[1d]. They did not have to wait long, as the new fleet attacked the Orks, and the XVIII were shocked to see it was was led by their unmet Primarch Vulkan. The Orks soon found themselves caught between the XVIII and the Primarch's Salamanders, and were quickly killed. Due to Fimbrus' efforts, Vaughn still lived and Vulkan promised he would make sure the Legion Master rose to fight once again.[1e]
- 1: Vulkan: Lord of Drakes (Novel)