Matt is a young boy growing up in an isolated house surrounded by poppy fields. He is the clone of El Patrón, the powerful dictator of Opium. Shielded from the outside world during his early years, he remains deeply curious about other children and his own origins. He possesses a natural talent for music and keenly observes his environment.

El Patrón is the 140-year-old dictator and wealthy drug lord who rules Opium. He grew up in extreme poverty and outlived all his siblings, leading to a deep sense of entitlement over the lives of others. He commands absolute obedience from his family and guards his possessions with severe intensity.

Celia is the chief cook at the Alacrán estate and Matt's devoted caretaker. She holds strong religious beliefs and frequently tells stories about the Virgin of Guadalupe to instill moral values in the young boy. She acts as a fierce protector, doing everything in her power to shield Matt from the prejudices of the larger household.

Tam Lin is a Scottish bodyguard with a rough past who serves El Patrón. He takes on a paternal role for Matt, teaching the boy outdoor survival skills and guiding his moral development. Unlike the rest of the estate's residents, he treats Matt as a human being capable of making his own ethical choices.

María is the compassionate younger daughter of a powerful senator. While her peers treat clones with disgust, she shows genuine empathy and insists on treating everyone kindly. She attends a convent school where she learns about Saint Francis, strengthening her belief that every living creature deserves respect.

Esperanza is a fierce, single-minded activist working to dismantle the corrupt systems of Opium. Through her writing, she exposes the brutal reality of the labor force and the violent methods of the Farm Patrol. She operates from outside the border, focusing her energy entirely on her political cause.

Tom is a mischievous and cruel boy who frequently visits the Alacrán estate. He maintains a polite, innocent facade in front of adult authority figures but displays vicious behavior toward those he considers vulnerable. He actively torments María and holds a deep-seated hatred for Matt.

Rosa is a servant at the Alacrán estate who harbors a venomous hatred for clones. When placed in charge of Matt's confinement, she treats him like an animal, locking him in a sawdust-filled room and neglecting his basic needs. She takes cruel pleasure in exerting total power over her helpless prisoner.

Steven is the teenage son of Mr. Alacrán. He is deeply prejudiced against clones and is quick to inform María of Matt's true nature. He follows the established rules of the household and expects others to conform to their society's strict social hierarchy.

Emilia is María's older sister and a frequent visitor to the Alacrán estate. She conforms easily to the expectations of Opium's elite society, sharing the widely held prejudice against clones. She often scolds her younger sister for showing kindness to those outside their social class.

Mr. Alacrán is the stern patriarch who manages the daily operations of the estate. He operates under the constant shadow of El Patrón's authority, maintaining strict order among the family and staff. He views clones with absolute disgust and enforces the household's harsh social hierarchy.

Felicia is Mr. Alacrán's sickly and reclusive wife. She spends much of her time confined to her rooms, sleeping or drinking to cope with her unhappiness. Despite her sluggish demeanor, she occasionally displays a passionate talent for playing the piano in isolated areas of the house.

Senator Mendoza is a powerful political figure from the United States. He aligns himself with the Alacrán family for political advantage and strictly adheres to the harsh social norms of Opium's elite. He expects unquestioning obedience from his daughters regarding their arranged futures.

Chacho is a street-smart Lost Boy living under the strict authority of the Keepers in Aztlán. He covers his vulnerability with a tough exterior but is deeply loyal to his friends. He holds on to the hope that his musician father will eventually return to rescue him from the orphanage.

Fidelito is a severely underweight eight-year-old boy working at the orphanage. Despite struggling to meet the strict daily work quotas and suffering from hunger, he maintains an optimistic attitude. He frequently recalls the gentle lessons his grandmother taught him before they were separated.

Ton-Ton is a quiet Lost Boy who works at the plankton factory and drives a large shrimp harvester. Initially appearing as a compliant follower desperate for the Keepers' approval, he hides sharp observational skills and a deep understanding of the factory's mechanical operations.

Jorge is a strict Keeper overseeing the Lost Boys at the plankton factory in Aztlán. He uses psychological manipulation and physical punishment to maintain total control over the orphans. He forces the boys into public self-criticism sessions to break their individual spirits and enforce conformity.

Carlos is a Keeper who manages the plankton tanks and enforces strict labor rules. He frequently lectures the boys about equality and the value of hard work, while hypocritically enjoying comfortable transportation and better food that he denies the laborers.

El Viejo is El Patrón's elderly grandson and Mr. Alacrán's father. Standing in stark contrast to his grandfather, he is a deeply religious man who accepts his natural aging process. He refuses to utilize Opium's advanced scientific implants to extend his life, choosing instead to rely on his faith.

Consuela is a kind older woman living in San Luis. She harbors a strong dislike for the Keepers and immediately offers the runaway boys shelter and safety during the local festival. She provides them with disguises to help them evade capture.

Guapo is an older man in San Luis who operates a hovercraft. He assists runaway youths by navigating the busy city streets and successfully evading the patrols of Keepers during the crowded Day of the Dead festival.

Eduardo is a scientist operating under immense pressure to grow a successful clone from cells that are over a century old. He lives in constant terror of failing his powerful employers, carefully monitoring the risky implantation process to ensure his own family's safety.

Daft Donald is a quiet, rough-looking Scottish bodyguard completely loyal to El Patrón. He communicates very little but effectively handles security operations around the vast estate, enforcing the dictator's will without asking questions.

MacGregor is a powerful, wealthy aristocratic figure known as a Farmer. He is a close associate of El Patrón and relies heavily on Opium's questionable scientific advancements to replace his failing organs and maintain a youthful appearance.