Replica

Humanity wages a brutal galactic war using clone soldiers to fight the human/alien hybrids known as The Not-Men. These clone soldiers aren't behaving as expected. One squad of five experiences id or ego divergence once they enter combat: One is a coward; Two's injured; Three's a psycho; Four's dead; and what about Five?

(story excerpt)

The crew compartment smelled of dried sweat, body odor, and death. Blood was under my fingernails. My black body armor was battered and filthy. All things I was intimately familiar with, if I could trust my memories.  

The guys sitting on the bench next to me and across from me all had my face. Not only that, they were me, exact replicas until the Dolen Corporation sent us into combat. Now there was divergence. Some of us were wounded, others burned or covered with mud and the blood of others. Some of us had killed, while others hadn't fired a shot. One of us, Number Four, didn't make it back when they recalled us. I'd seen him die.