Sancho sails as Mendoza's associate, hired for the New World voyage. His portly physique frequently draws attention alongside his hearty enthusiasm for food. Driven by an obsession with discovering gold, he often prioritizes this pursuit over other concerns, including the children's welfare.

Inseparable from Pedro, Sancho forms a comedic duo defined by shared greed and clumsy antics that repeatedly plunge them into trouble. Despite constant doubts and complaints, both display unwavering loyalty to Mendoza. Sancho's noticeable stutter surfaces during danger, underscoring his cautious and easily frightened disposition.

Though not inherently wicked, his clumsiness and gold-focused instincts inadvertently complicate situations for the group. He relies heavily on impulse, particularly when riches are involved, serving primarily as comic relief throughout the narrative.

Sancho appears consistently: across the initial journey in episodes 1–10, 12, and 14–39, and in all 26 episodes of the second season within Mendoza's group. He ultimately departs South America with Pedro and Mendoza, returning to Spain after salvaging modest gold—a stark contrast to their ambitions. During their parting, Mendoza hints at a potential reunion with the children.