Sanctus Reach: Death Mask is a short story by Cavan Scott, a tie-in to Games Workshop's Sanctus Reach expansion. It was published online in July 2014.
As the Red Waaagh! rages through the Sanctus Reach, the defenders of Ghul Jensen prepare for the inevitable onslaught. But an enemy lurks within that may doom their defence before it ever starts. In the spires of Hive Vinter, a cult has sprung up, worshipping the greenskins and their savage deities. If the traitorous denizens of the hive can link up with the main ork advance, Ghul Jensen will be doomed. There is only one answer, one way to end the threat with a single blow: the death of the cult’s leader at the hands of an Imperial Assassin.