Event · M41
Diamor Campaign
The Diamor Campaign was a Forty-first Millennium conflict between the Blood Angels and the Black Legion, centred on Diamor. It belongs to the long series of engagements in which the Imperium’s Adeptus Astartes have met the warbands that descend from Abaddon’s Black Legion, the largest surviving Traitor force since the Horus Heresy. The campaign is recorded chiefly as a Blood Angels action, and it is best read alongside the Chapter’s other wars against Chaos in the same millennium. The cause of the fighting is recorded as the ordinary pressure that Chaos Space Marine warbands exert on Imperial worlds: raiding, corruption of local populations, and the seizure of territory from which further incursions can be launched. The course of the campaign is that of a sustained struggle rather than a single battle. Blood Angels forces were committed against Black Legion elements, and accounts differ on the size of the warbands involved, the length of operations, and the detail of individual engagements. Those details are not set out here where canon does not settle them. The Blood Angels’ approach to such wars is shaped by the Chapter’s inherited flaws, the Red Thirst and the Black Rage, which have coloured how their commanders weigh aggression against restraint. On Orrery the campaign is anchored to Diamor on the map and to the Forty-first Millennium on the timeline, with the Blood Angels and the Black Legion as its linked participants. Its contemporaries are the many Chaos incursions that the Imperium contested during the same millennium, including the wider Black Legion offensives that culminated in the Thirteenth Black Crusade. The aftermath is recorded as a further entry in the enmity between the Sons of Sanguinius and Abaddon’s followers, rather than as a decisive turning point in the galactic story. Later tradition treats Diamor as one more contested position in the Imperium’s continuing defence against Chaos.
See where Diamor Campaign occurred on the galactic map in the 41st Millennium.