The Speaker
The speaker in this particular work is anonymous; he witnesses the battle and describes it in the third-person perspective. It is possible he is a soldier who fought on the front lines in the war, as evidenced by the plea at the end of the poem. Regardless of who the speaker is, he represents the common man.
The Soldiers
The soldiers in the poem are gray-faced with fear as they make their way into the violent chaos of battle. They are indistinguishable as individuals, suggesting that war obliterates personal lives. Their muttering could be suggestive of shell shock, a condition that afflicted soldiers exposed to combat up close.
Jesus
At the end of the poem, the speaker pleads to Jesus to put an end to the violence of war. This appeal to a higher power demonstrates the desperation and fear that the soldiers felt. No matter what reasons led them to enlist, the horror of battle has drained them of hope.