Andrea Durcal
Beginning the story as a nine-year-old, Andrea grows into adulthood as the protagonist. She's a pretty hateful, ignorant child, having been raised in extreme privilege by her wealthy father in a poverty-stricken border town. Unlike her peers, Andrea doesn't worry about money, food, safety, religion, or even her grades. She accepts no responsibility in her life, preferring to indulge every whim, regardless of its negative effect on other people. Although she's not particularly lovable, Andrea's problem is not hers to begin with. Her parents spoiled her and failed to instruct her in the values of humility, empathy, or charity. As an adult, however, Andrea comes to realize how selfishly and recklessly she has been living all these years. She decides to change her priorities and to participate in life beyond her own bubble of desires.
Victor
Victor is Andrea's cousin, also her same age. He is her constant companion throughout childhood and into young adulthood, Andrea's father having financed his education at boarding school alongside Andrea. Because they both share privilege, they are each other's only friend. The rest of the school despise the two of them. More bold than Andrea, Victor comes up with the ideas for their adventures. He's also the mastermind of the theft of the prostitute's money. As an adult, he becomes overwhelmed by his guilt and grief over causing that woman's death, so much so that he commits suicide. He desperately had wanted to leave the town and the overt disdain with which everyone treated him because of the prostitute's exposure and death.
The Shopkeeper/Prostitute
This woman treats Andrea and her cousin poorly, like most of the adults. She sees their privilege and how hatefully they exercise it. When she slights them, however, she ends up becoming the recipient of their greedy schemes. By the time Andrea and Victor rob her, this woman's reputation has been completely ruined by them. They told the entire town -- including her husband -- that she's been moonlighting as a prostitute. Eventually she's threatened and murdered by an angry ex.
Andrea's Father
He is a wealthy many, living near the border to take advantage of the cheap land. He has married an American, signifying his rejection of his cultural heritage. He raises Andrea largely in the American fashion, providing for her every desire. To him, she is an object to be preserved and spared the horrors of the real world, the world of the townspeople, but he ends up spoiling her far beyond recognition.