Kino is a young, yet hard-working individual, who's enjoys and benefits from diving in the ocean. Later in the novel, Kino finds the Pearl of the World, granting his family high amounts of wealth.
Juana is the wife of Kino, who deems the Pear of the World as evil and should be returned. With lots of convincing from Kino, Juana agrees to keep the pearl, as it is their only hope to save Coyotito
Coyotito, the son of Juana and Kino, was stung by a scorpion early in the novel. This caused for Kino and Juana to search for a doctor, who would not treat Coyotito because of their economic status. This later led to the discovery of the Pearl of the Worlds.
The doctor is Coyotito's only form of hope, after the sting of the scorpion. The doctor desired to live a wealthy lifestyle. Once he found out that Kino and Juana had the Pearl of the World, he was willing to help Coyotito, in hopes of receiving the pearl as pay. The pearl could possibly grant the doctor enough money to make his dream come true.
Juan Tomas is Kino's older brother, who is trusted by Kino and his family. Juan provides support for the family, and warns Kino of the dangers of having the pearl because of its high value.
The pearl buyers knew of Kino's discovery of the pearl, and then offered Kino low amounts of money for his pearl. The pearl buyers are attempting to get the pearl by offering low prices, since they know he is poor.