The Second Purging of Lastrati occurred in 543.M36, as a part of the Athalor Crusade, under the command of Marshal Gervhart of the Black Templars Space Marine Chapter. During Lastrati's tumultuous past a sect known as the Divine Army had gained control of the unremarkable Hive World of Lastrati, located in the Ultima Segmentum. The Divine Army preached a doctrine of intolerance of those with even the slightest deviation from what their leaders viewed as the physical attributes of the perfect human being. They created genetically-tailored viruses that targetted particular traits, eradicating whole swathes of the population. When Imperial contact was re-established with this remote planet, only 2.5 million inhabitants were left of a world that had once boasted a population of 14 billion.
Lastrati had become a place of pilgrimage, and for centuries, the faithful had come to bear witness to such spectacles as the Hill of Heretics and the Plain of Purity. Marshal Gervhart and the Black Templars of the Athalor Crusade had come to Lastrati to take heart from the planet's potent displays of faith from the past, but were horrified by what they found. The Quintarchs of Lastrati had turned to barbaric blood rituals and human sacrifices in search of genetic perfection. At first the Space Marines were welcomed as examples of genetic supremacy, but the more the Black Templars saw, the more they realised that the rituals of the people of Lastrati had too much in common with the heretical cult worship of the Ruinous Powers. Marshal Gervhart ordered the planet cleansed of its degenerate inhabitants before continuing the Crusade. After four standard years of fighting, the warriors of Marshal Gervhart forced the remaining forces of Lastrati back into the Plain of Purity where they made their last stand before the Black Templars at the Hill of Heretics. The army was destroyed, the Black Templars showing no mercy and accepting no surrender. Those deemed free from taint were allowed to live - an act of mercy that was to have repercussion for Marshal Gervhart in later years.
- Codex: Black Templars (4th Edition), pg. 19
- White Dwarf 312 (UK), "Righteous Victories" by Graham McNeill, pg. 21