Warhammer 40k - 2013 Advent Calender Short Story - Lysander: Fist of Dorn by Anthony Reynolds

Darnath Lysander is a man tortured by his past, a past in which the Iron Warriors play a prominent, and unpleasant, role. As the First Captain of the Imperial Fists must choose between the lives of innocents and the death of one of Perturabo’s sons, he recalls a similar incident that haunts him still, and must decide what mistakes are worth repeating.