Anthony Reynolds
Lysander: the Fist of Dorn

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.
Warhammer 40k
short

Also in:
Imperial Fists: Quick Reads Collection