The Fallen Soldier
We know that Wilfred Owen wrote most of his poetry in a short period of time all while fighting in the horrific battles of WWI. We're no psychologists, but it's pretty plain to see that all of that fighting had a tremendous impact on his poetry.
While he has dedicated almost all of his poems in one way or another to the horrors of war, we think he had a particular interest in the fallen (or soon-to-be fallen) soldier. These guys had the real short end of the stick. If they weren't having to deal with the fear of their own death, they were dealing with the destructive guilt of being responsible for someone else's death. You can see other examples of this in the (un) cheerily titled "Anthem for Doomed Youth" and in his most famous poem "Dulce et Decorum Est." Unfortunately for Owen, he got to experience the suffering and death as a soldier, and his poetry, especially "Strange Meeting" illustrates this perfectly.