First Hell Crusade

The First Hell Crusade was a massive joint-Imperial defensive campaign conducted by several Space Marine Chapters including: the Golden Castellans, Knights of the Anvil, Spartiate Marines, Lightning and the Templars Moline, against a massive Chaos incursion from the nearby dual-warp rifts, known as the Hellgates, in defence of Sector Occident Prime.

Background
The Hellgates are a pair of relatively small warp rifts located in the Thermopylae sub-sector. In M36, the Hellgates were still a part of the ancient Loculus sub-sector, located in the area of the galaxy known as Sector Occident Prime. These dangerous warp rifts are located only 1,000 light years from the Imperial Throneworld of Terra. This region has long been a haven for renegades, outcasts and the followers of the Dark Gods. Within the Hellgates, these hellish realms of Chaos are ruled by all four factions of the Ruinous Powers, who constantly vie with one another for absolute supremacy. Daemonic incursions and the predations of marauding Chaos warbands have been common for millennia.

In 110.M36, a massive Slaaneshi warhost led by the Daemon Prince, Xeraz the Exquisite, and his Chaos allies, erupted from the hellish pleasure realms within the Ashaklun Gate, and soon the entire sector was embroiled in bloody conflict. Receiving multiple astropathic calls for assistance, the Golden Castellans Chapter, located in the nearby Gathalomar Sector, send their entire Chapter in response to this grave threat. Several other nearby Space Marine Chapters - including the Knights of the Anvil, Spartiate Marines, The Lightning and the Templars Moline - respond to the threat, rushing to commit their strength to the rapidly escalating war. Though several worlds burn in the fires of destruction, and the shadows gather close, throughout the sector, the Emperor's avenging Angels of Death stand fast, determined to save the besieged Imperial worlds of this sector or die in the attempt.

Leading the Imperial defence of the besieged sector, the Golden Castellans spearheaded the fleet of Battlefleet Loculus against the vast Chaos armada. Utilising their flagship, the Incursus Defensior, a Ramillies-class Star Fortress, this colossus of war utilised its formidable firepower to fight valiantly in many major battles against the Forces of Chaos. After nearly eight decades of bloody conflict, this mighty vessel becomes the lynchpin in the blockade of the Hellgates, and eventually plays an instrumental role in turning the tide of the conflict, driving the Chaos armada back into the swirling eddies of the Hellgates.