Irrellian Sector Incursion

The Irrellian Sector Incursion was a notorious campaign conducted by a mysterious, unidentified Heretic Astartes strike force that attacked an Imperial Navy battlegroup in the Irrellian Sector. This battlegroup was utterly annihilated. Later, Imperial investigation revealed that the most likely culprits were the Keepers of Equity Chaos Warband.

History
In M37, an Imperial Navy battlegroup in the Irrellian Sector intercepted what appeared to be a lone chaos space marine vessel fleeing from a much larger vessel of unknown origin. Before the battlegroup could intervene the smaller vessel was rent into dust by an unknown force and the ship disappeared into the warp. At this time it is believed that the ship was the same vessel that took part in the attack on the Bloodborne.