Mustafa is a highly intelligent North African man born in Azemmur. Against his father's wishes, he initially works as a successful merchant until a severe famine drives him to sell himself into slavery to save his family from starvation. Renamed Esteban and later Estebanico by his European captors, he demonstrates a remarkable talent for languages and negotiation. While marching through the Americas, he acts as a translator and healer, constantly longing for his homeland and regretting his past participation in the slave trade.

Dorantes is an ambitious Castilian gentleman who leaves a comfortable life in Seville to seek fortune and glory in the Americas. He purchases Mustafa with a golden earring and brings him on the Narváez expedition. As the strict hierarchy of the Spanish colonial system breaks down in the wilderness, he relies heavily on Mustafa's survival skills and translation abilities, forcing a shift in their dynamic.

Narváez is the governor and official leader of the Spanish expedition. He is an arrogant and inflexible commander whose total lack of empathy dooms the hundreds of men under his charge. Blinded by greed, he obsesses over finding an imaginary kingdom of gold called Apalache, ignoring the advice of his officers and actively torturing Indigenous people to extract information.

Cabeza de Vaca serves as the treasurer of the expedition and is the highest-ranking officer to survive the disastrous march. He is an observant and articulate man who initially supports Narváez's poor decisions. As a gifted storyteller, he knows how to hold an audience's attention, a skill he uses both to survive in the wilderness and to manipulate the official Spanish records in his favor.

Castillo is a young Castilian nobleman who joins the expedition against his father's wishes, lured by Dorantes's promises of wealth. Initially reliant on the approval of others, he proves to be practical and cautious, often voicing correct but ignored objections to Narváez's plans. Over time, living outside of European society brings out his natural resilience and good humor.

Muhammad is Mustafa's father. Once a university student in Fes, he moves his family to Azemmur where he works as a notary. Known as "Muhammad the Lame" after losing an arm to a Portuguese soldier, he is a proud man who deeply desires for his son to study the Qur'an and follow him into the legal profession.

Mustafa's mother is a resilient woman originally from Fes who works tirelessly to keep her household together. She is a gifted storyteller who uses parables to warn Mustafa against the dangers of greed. When famine strikes Azemmur, she attempts to sustain her large family on mere broth and begs Mustafa not to sell himself into bondage.

Rodriguez is a Spanish merchant and Mustafa's first enslaver. He is a volatile man who renames Mustafa "Esteban" and frequently subjects him to cruel beatings, including kicking Mustafa for praying toward Mecca. His heavy drinking and gambling eventually force him to sell Mustafa to cover his debts.

Ramatullai is an enslaved woman who forms a deep bond with Mustafa while they are both owned by Rodriguez. Renamed Elena by her captors, she carries the grief of losing her husband to violence and having both of her daughters sold away. She and Mustafa find solace in sharing their true names and stories with each other.

Oyomasot is the daughter of an Avavares shaman who becomes Mustafa's wife. She acts as his partner in his healing practice, cleverly turning his cures into rhymes to add a sense of spectacle. She provides Mustafa with a sense of belonging and respects his abilities, though this respect is challenged when they encounter Spanish colonial forces.

Diego is Dorantes's younger brother who accompanies him on the Narváez expedition. Unused to manual labor and harsh conditions, he struggles significantly when forced to dig for roots and fend for himself in the wilderness.

Léon is a soldier originally from Cabeza de Vaca's camp. He is a boastful and antagonistic figure who openly brags about participating in violence against Indigenous women. He clashes intensely with Mustafa, eventually falsely accusing him of theft.

Ruíz is a deeply distrustful and openly disobedient soldier on the expedition. He frequently defies direct orders from his superiors, preferring to act on his own paranoia regarding the Indigenous people. His insubordination leads him to splinter off from the main group entirely.

Father Anselmo is a friar attached to the Narváez expedition. He displays occasional bouts of conscience regarding the treatment of captives and eventually becomes so disillusioned by the horrors of the expedition that he chooses to abandon the Spanish mission to live among the natives.

Martín is one of the soldiers who deserts the failing expedition early on. Having survived by swimming to the mainland, he delivers grim news about the fate of the other men and decides his best chance of survival is to integrate fully with the local Indigenous populations.

Balsehekona is a leader within the Carancahua tribe. He interacts with the surviving Europeans out of practical necessity, offering them food but strictly enforcing his authority by punishing them severely when they break his rules or fail to contribute.

Chaubekwan is a healer for the Yguaces tribe. He is curious about the survival methods of the castaways and invites them to his village, where he eventually teaches Mustafa the foundational skills of traditional Indigenous healing.

Tekotsen is an Indigenous woman who marries Dorantes while he lives among the native tribes. Her marriage and social standing are heavily jeopardized when Dorantes re-enters Spanish society and refuses to formalize their relationship in a Christian church.

Satosol is Dorantes's Indigenous brother-in-law. He has a natural flair for theatrical performance, assisting Mustafa by translating and elevating his healing sessions into public spectacles. He later makes independent choices about aligning with Spanish governors.

Alcaraz is a Castilian officer leading a group of soldiers in the Americas. He embodies the ruthlessness of the Spanish empire, showing no interest in peaceful coexistence and openly declaring his mandate to capture and enslave the Indigenous people who accompany the survivors.

Guzman is the governor of Compostela, a man whose reputation for mistreating natives precedes him. Coarse and obstinate, he refuses to acknowledge the humanity of the Indigenous populations and aggressively pressures the survivors to surrender their geographical knowledge for future conquests.

Mendoza is the viceroy of New Spain and the most powerful man in the territory. He views the survivors' journey primarily as a tool to aid future colonization, demanding official testimonies and constantly seeking men to lead new expeditions in search of the mythical Seven Cities of Gold.

Cortés is the famous conquistador responsible for the destruction of Tenochtitlán. Wealthy and highly influential, he attempts to leverage his resources to acquire Mustafa from Dorantes, recognizing Mustafa's immense value as a guide and interpreter for future missions.

Coronado is a newly appointed Spanish governor tasked with finding the Seven Cities of Gold. He pays lip service to a new era of peaceful expansion but allows his men to keep enslaved captives. He relies heavily on Mustafa's scouting abilities while threatening brutal punishment for any betrayal.