What are the motifs in The Underdogs a Novel of the Mexican Revolution by Mariano Azuela?

One of Demetrio's key attributes is that he has little capacity for introspection and, on the other end, little concern or understanding of the larger meaning of the revolution; at one point, he tells General Natera he is only a loyal soldier and only wants to be told what to do. The character of Luis Cervantes provides this sense of a larger picture (as an intellectual and journalist). He is the outsider who, like the reader, questions the very nature of Demetrio's rebels, wondering if they are the people's heroes or merely murderers using the revolution as a pretext. He gives reasons for the men's behavior, justifying the rampant looting as payments by the people to the soldiers fighting for them.