Betrayal at the Bloody Crag

The Betrayal at the Blood Crag is a little known campaign that took place sometime during the wider events of the Indomitus Crusade that was launched by the Imperium of Man following the formation of the Great Rift after the destruction of Cadia during the 13th Black Crusade.

History
The Fortress World of Ursax had fallen to the forces of Chaos of the Cult of the Bloody Hand during the terrible times known as the Noctis Aeterna, severing a line of fortified worlds that acted as bulwark against the rising tide that threatened to engulf the Imperium Nihilus, the Skull Reapers were determined to retake it and make an example to all in the process. Fielding their entire Chapter save those garrisoning Iceni along with Regiments of the Astra Militarum. Landing in full force the Imperial forces drove the enemy back meter by meter to the formation designated as Ridge-140 now known as the Bloody Crag when a betrayal of the basest kind took place, the Skull Reapers allies turned on them and willingly joined with the Heretics and  launched a brutal counterattack, caught between these 2 forces and outnumbered by almost 50 to 1 the Astartes of the Skull Reapers showed all the resilience they have become legendary for and launched assault after brutal assault, the Reaper Lord and his brothers reaping an horrific tally of dead the Skull Reapers emerged victorious and purged all life from the corrupted world, once the smoke had cleared just 19 Skull Reapers lay dead as for the heretic forces they had been utterly wiped from the face of existence and the names of these traitors expunged from history so completely that future generations will never know they even existed.