Ramón is a sixteen-year-old boy living in La Paz who recently became a partner in his father's lucrative pearl business. He is small and thin for his age, causing him great insecurity regarding his masculinity and his ability to carry on the family legacy. Eager to earn his father's respect and outdo the boastful divers in their fleet, he secretly pays an indigenous diver to teach him how to harvest pearls in a dangerous, isolated lagoon.

Blas is the most famous dealer of pearls on the Vermilion Sea and the proud owner of a fleet of five diving ships. He is a tall, physically imposing man whose bronze skin reflects years spent managing expeditions on the water. Highly concerned with social status, reputation, and wealth, he views the ocean primarily as a resource to be exploited for his family's continued prosperity.

Known throughout the town of La Paz as "the Sevillano," Gaspar is the strongest and most successful pearl diver currently working in the Salazar fleet. He claims to be from Spain and covers his body in tattoos depicting his unverified triumphs over dangerous animals like octopuses and mountain lions. He openly disdains anyone he considers physically weak and flatly refuses to respect local superstitions.

Soto Luzon is an indigenous pearl diver who lives near a hidden, black-sand lagoon and maintains a traditional relationship with the ocean. He approaches pearl diving with extreme caution, harvesting only what he needs rather than exploiting the waters for mass profit. He firmly believes in the local legends of the sea and tries to impart this spiritual caution to younger, more reckless divers.

Father Gallardo is the local Catholic priest in the town of La Paz. He presides over the religious life of the community and acts as a spiritual authority for the wealthy pearl dealers. He views the natural bounty of the sea as a potential tool for church influence and dreams of using local miracles to aid his missionary work among the indigenous populations.

The Manta Diablo is a legendary, massive manta ray believed to inhabit a secret cave in Soto Luzon's lagoon. According to local lore, it was exorcised into the sea a century ago by a priest and now jealously guards the black pearls of the Vermilion Sea. To the indigenous people and superstitious townsfolk, it represents the unpredictable and dangerous forces of the ocean that punish human greed.

Ramón's mother is a protective presence in the Salazar household who worries constantly about the dangers of the Vermilion Sea. She relies heavily on her Catholic faith and the local priests for comfort when the men in her family are out on the water. She enjoys the financial comforts her husband's business provides but prefers to ignore the physical risks involved in acquiring them.