The Coronis Campaign began when the massive Hive Fleet Scarabus, invaded the Sector of the Imperium world of Coronis. World after world fell before the ravenous swarm, as the Imperium's forces sent to stop the Tyranids were easily swept away. Soon Coronis lay in Scarabus' path and several Regiments of the Imperial Guard were sent to quickly dig into the world to repel the Hive Fleet. As the Tyranids began to darken Coronis' sky however, a vision of the Emperor was received that revealed a critical weakness in Scarabus' implacable advance. The Imperium's forces in the Sector were filled with new hope, as the vision showed the time to defeat the vile Tyranid scourge was nigh.