Defense of Vaeturn

The Defence of Vaeturn was a defensive campaign carried out by the Penitent Knights newly received Primaris Space Marine brethren, in support of the Aegimius System's forge world of Vaeturn from the predations of large force of Heretic Astartes.

History
With the Cicatrix Maledictum torn open and the galaxy split in twain, the Penitent Knights began efforts to reinforce the Aegimius System against the horrors pouring out of the enormous Warp Rift. With the entirety of the Chapter's fleet defending the Fortress-System, the minions of Chaos were held at bay for a few brief years until a host of Chaos Marines broke through a weakness in the Penitent Knights' void patrols and were poised to assault Aegimius' forge world Vaeturn. And thus, the Primaris of the Orders of the Winterbound and Gryphon were given their first challenge in a hurried support of the forge world.

However, due to the seeming dour nature of the Primaris Knights, unit cohesion was much more difficult between the new and old guard. Moreover, the Primaris Knights argued that it was best they focus on protecting solely the crucial factorums and leave the hab-blocks undefended, to the deep chagrin of their older brothers. While most of the Primaris accepted their orders, Primaris-Sergeant Alissar abandoned his quarter of civilian housing to reinforce the factorums, leaving the mortal workers to be slaughtered in their homes by Chaos' minions. When after days of continued war, Vaeturn was successfully defended, Alissar was shown the thousands of innocents slain by his disregard for them. And so, in shame and guilt, Alissar became the first Primaris Justicar, to mete out death to the Chapter's enemies armed with only a power sword to atone for deeds committed.