The irony of the underdog
An underdog is simply someone who is disadvantaged, someone who is given extra burdens that they have to account for before they can do other things. For the poor, that means every day is a survival day. Then, there is the poor who are accustomed to getting what they want. They are so spoiled that even the law bends it authority to them—they can bribe Mexican officials easily and frequently, because who will stop them? In this novel, the underdog is the hero, and the power is evil. That is ironic, given the role the government plays in society.
The irony of Camila
For just a split second, the reader might see Camila and be charmed by her as Macías is, but actually, Macías is already married, so ironically, the very aspect of Camila's personality that is most likable is the one she is using for dubious purposes. She is not interested in marrying Macías, which makes them compatible, because what Macías really wants is a warm body during his journey. The relationship seems sweet on the surface, but it's complex and thought-provoking at best.
The irony of Margarito and Cervantes
Since these two men are something like foils for one another, they can be seen for their irony, because such different men are on the same team, and neither of them are strong enough to win, and the same fate befalls all the Underdogs. So, why are they together? Because their different, opposite approaches to life leave them with different skill sets.
Margarito as a hero
Here's the gist of Margarito's character: he's an unpleasant guy who is so entitled that he steals from innocent, unsuspecting people, and he judges others harshly while he abuses them and exploits them. But, he is a hero, because these broken aspects of his character do provide some valid, true insights on occasion, meaning that at least in some way, he's right about something. Also, he doesn't feel beholden to the rules, which although shameful, does make him an advantage to the team, because he doesn't mind doing the dirty work of a painful, difficult revolution.
The irony of loss
At the end though, they all die, which sounds like they failed or something, but actually, the irony of their loss is a reminder that their death is not a symbol for failure, but of their humanity. The reader is presumably also a human, so therefore, the loss is a death reminder. By remembering the end of the human life, the rest of the story is put into perspective. The value of the revolution was not real, it was mythic, because it symbolizes the resilience of downtrodden humans.
