Many literary devices are used in Ambrose Bierce's Chickamauga. If you look at the first paragraph, the way it is written is "foreshadowing" that is telling the events that will come later. You can tell by the words he uses. The picture he paints with his words are dark and forboding. The boy is not only a boy, but represents all boys. (symbolism)
Looking at the third full paragraph below, you can see the literary device, "symbolism" utilized:
Advancing from the bank of the creek he suddenly found himself confronted with a new and more formidable enemy: in the path that he was following, sat, bolt upright, with ears erect and paws suspended before it, a rabbit! With a startled cry the child turned and fled, he knew not in what direction, calling with inarticulate cries for his mother, weeping, stumbling, his tender skin cruelly torn by brambles, his little heart beating hard with terror--breathless, blind with tears--lost in the forest! Then, for more than an hour, he wandered with erring feet through the tangled undergrowth, till at last, overcome by fatigue, he lay down in a narrow space between two rocks, within a few yards of the stream and still grasping his toy sword, no longer a weapon but a companion, sobbed himself to sleep. The wood birds sang merrily above his head; the squirrels, whisking their bravery of tail, ran barking from tree to tree, unconscious of the pity of it, and somewhere far away was a strange, muffed thunder, as if the partridges were drumming in celebration of nature's victory over the son of her immemorial enslavers. And back at the little plantation, where white men and black were hastily searching the fields and hedges in alarm, a mother's heart was breaking for her missing child.
In this paragraph Bierce uses these small animals as "enemies" because they are symbols as the inherent nature of this common boy to go to war, to fight and to kill.
In the next two paragraphs the little boy sees men who have been maimed by war. Bierce describes them as a man would see them but also reminds the reader that as a boy, he would not see them as plainly. The boy laughed and reacted as a child acts when someone is playing with him. This technique just exacerbates the trauma of the situation. Bierce is so exacting in his portrayals of the ruthless maiming of human beings in war. This is the beginning of the conflict. The conflict is between how the boy should react to death and how he really reacts. The reader is appauled and disgusted by his reaction. We know he doesnt understand what is happening. As readers, we wait for him to understand, to react appropriately.
At the very end, the child sees his dead mother. This is the climax. Finally he reacts correctly, in terror. But terror is a mild word because Bierce's decription of the boy's reaction is that of utter devastation. In the end, the boy finally understands death. The boy is reacting to the worst fear of any and all children--total abandonment. Even he knows , at his young age, that he is totally alone in this world.The reader can see this in the boy, at the end, he cannot handle it. He is devastated.
This is the message Bierce wants his readers to understand: war is total devastation. War is hell.