The Invasion of Nova Sulis was a notable campaign conducted by the savage Executioners Space Marine Chapter against the Heretic forces of the Apostate Cardinal Bucharis during the Plague of Unbelief, upon the world of Nova Sulis in 302.M36. During the wars that marked the beginning of the Plague of Unbelief, the Executioners were among the first Space Marine Chapters who took up arms against Cardinal Bucharis' splinter empire based at Gathalamor, notably fighting alongside the Space Wolves, Angels of Absolution and Raven Guard at various points during the conflict. Their most famous action during this time was the invasion and subsequent devastation of the Hive World of Nova Sulis.
The avaricious water-barons of Sulis had been eager supporters of the Apostasy, taking the Cardinal's stolen wealth in return for vast quantities of munitions produced in their hive-manufactora, which in turn were being ploughed into Bucharis' disastrous ongoing siege of Fenris, the Space Wolves' Chapter homeworld. Falling like a flaming comet on their victims, the Executioners invaded Sulis in force, their warships blackening the skies and raining death on the baronial estates and storehouse-palaces, while their armoured assault forces swept through the manufactora districts like a scythe, slaying everything that opposed them and laying waste to vast swathes of the planet's surface. It was said later in the whispers of those that survived this terrible day of wrath that only those that prostrated themselves before the dark-armoured giants in surrender were spared. But every man or woman that raised up arms against the Executioners, be they Guardsmen, noble, priest or hive scum, were struck down. With Nova Sulis devastated and the supplies of munitions to Bucharis' traitors cut off, the Executioners departed, leaving the severed heads of those they slew lining kilometre after kilometre of the wrecked city streets. With the government literally beheaded and the planet's infrastructure in tatters, the wild fires and secondary explosions from the destruction they had wrought spread like a crawling plague across the world that would last for years before they were finally curbed. For their role in combatting the apostates and Traitors of the Plague of Unbelief, the Executioners were given the rare honour of having a new Chapter, the Iron Champions, being raised from their gene-seed in a later Founding.
- Imperial Armour Volume Ten - The Badab War - Part Two, pp. 87-88