Devala Uprising

The Devala Uprising was an Imperial xenocidal purgation campaign conducted by the Shattered Star Space Marine Chapter who were tasked to bring the wrath of the Emperor down upon the Imperial world of Devala, after failing to turn over their planetary tithes to the Administratum over several decades. Upon further investigation, the Chapter discovered that the rot of corruption had spread further than they originally thought - the planet's nobility had been infiltrated by Genestealers over several generations. Within a matter of weeks, the planet was fully purged by the unforgiving Chapter.

History
The planet of Devala was a rich mining colony that was ruled by the high priest, that changed when he gave power to a noble family out of random. Within the next few centuries the family became more and more powerful, first they controlled the Factorums, then the local munitorum, and then the local church. While the family became more powerful the planetary tithes became less and less. Before this problem was taken care of the family made planet revolt against Imperial rule, luckily the Shattered Star saw this planet revolt in the Pathfinder's vision and so traveled to Devala. When the chapter assaulted the traitor guardsmen the family revealed their true allegiance the genestealers, while the chapter managed to cut through cult's forces their headquarters a mighty fortress. The company had to enter the fortresses' catacombs, with the companies armour laying siege to the fortress. After a few weeks of purging the chapter came out victorious.