Carlota is the 14-year-old daughter of Doctor Moreau. Having grown up completely sheltered on a remote estate in the Yucatán Peninsula, she is deeply connected to the natural world and the hybrid creatures her father creates. She is largely ignorant of the outside world but fiercely loyal to her home and those living within it.

Montgomery is a 29-year-old English expatriate carrying the heavy emotional baggage of an abusive childhood and a tragic family history. He relies heavily on alcohol to cope with his guilt and dark worldview. Despite his hardened exterior, he possesses a strong sense of empathy and quickly becomes protective of Carlota, remaining highly wary of the estate's strange dynamics.

Doctor Moreau is a brilliant, highly secretive French scientist running a remote estate in Mexico. He spends his days conducting strange biological experiments to create human-animal hybrids with funding from a wealthy patron. He views himself as a god-like figure to his creations and expects absolute deference from everyone on the estate, including his daughter.

Eduardo is the handsome, privileged son of Hernando Lizalde. Accustomed to the wealth and power of his family's position in Mérida society, he views the world through a lens of entitlement. He quickly becomes infatuated with Carlota, bringing the complications of the outside world into her isolated existence.

Hernando Lizalde is a wealthy, ruthless Mexican landowner who bankrolls Doctor Moreau's controversial experiments. He views the hybrid creations purely as a potential source of cheap, docile labor for his vast plantations. He is driven by greed and a desire to maintain absolute control over his properties and workers.

Lupe is one of Doctor Moreau's hybrid creations, possessing a mix of animal and human traits. She functions as a sister and closest confidant to Carlota, often sneaking around the estate to uncover its secrets. Despite her youth, Lupe harbors a growing awareness of the oppressive conditions they live under.

Cachito is another of Doctor Moreau's hybrid creations living at Yaxaktun. Like Lupe, he acts as a playmate to Carlota but suffers under the strict disciplinary measures enforced by Doctor Moreau. He is restless and desires freedom from the estate's confines.

Ramona is the housekeeper at Yaxaktun who helps manage the domestic affairs of the isolated estate. She provides practical care for Carlota and the hybrids, operating quietly in the background while maintaining her own private views on the doctor's operations.

Isidro is Eduardo Lizalde's cousin and traveling companion. He represents the prejudiced, upper-class society of Mérida, openly displaying suspicion and distaste toward the unusual inhabitants of Yaxaktun. He views Carlota's dark features and the existence of the hybrids with harsh judgment.

Juan Cumux is an Indigenous Mayan rebel leader organizing forces against the wealthy estate owners in the Yucatán Peninsula. Though operating off-page initially, his presence creates widespread fear among landowners like the Lizaldes, driving much of their desire for a hybrid labor force.

Melquiades is the previous mayordomo of Yaxaktun who departed the estate a year before Montgomery's arrival. His absence creates the job vacancy that brings Montgomery into the isolated world of Doctor Moreau.

Elizabeth is Montgomery's deceased sister who suffered horrific abuse at the hands of their father. Montgomery abandoned her when he fled to the Americas, a decision that haunts him endlessly and shapes his protective instincts toward vulnerable women.

Fanny is Montgomery's socially ambitious ex-wife. Montgomery drained his financial resources attempting to give her the luxurious life she demanded, a choice that prevented him from saving his sister and left him destitute and bitter.