Santiago
Santiago is the protagonist of the novella. He is an old fisherman in Cuba who, at the beginning of the book, has not caught anything for eighty-four days. The novella follows Santiago's quest for the great catch that will save his career. Santiago endures a great struggle with a uncommonly large and noble marlin only to lose the fish to rapacious sharks on his way back to land. Despite this loss, Santiago ends the novel with his spirit undefeated. Depending on your reading of the novel, Santiago represents Hemingway himself, searching for his next great book; an Everyman, heroic in the face of human tragedy; or the Oedipal male unconscious trying to slay his father, the marlin, in order to sexually possess his mother, the sea.
Manolin
Manolin is Santiago's only friend and companion. Santiago taught Manolin to fish, and the boy used to go out to sea with the old man until his parents objected to Santiago's bad luck. Manolin still helps Santiago pull in his boat in the evenings and provides the old man with food and bait when he needs it. Manolin is the reader's surrogate in the novel, appreciating Santiago's heroic spirit and skill despite his outward lack of success.
The Marlin
Although he does not speak and we do not have access to his thoughts, the marlin is certainly an important character in the novella. The marlin is the fish Santiago spends the majority of the novel tracking, killing, and attempting to bring to shore. The marlin is larger and more spirited than any Santiago has ever seen. Santiago idealizes the marlin, ascribing to it traits of great nobility, a fish to which he must prove his own nobility if he is to be worthy to catch it. Again, depending on your reading, the marlin can represent the great book Hemingway is trying to write, the threatened father of Santiago's Oedipus, or merely the dramatic foil to Santiago's heroism.
The Sea
As its title suggests, the sea is a central character in the novella. Most of the story takes place on the sea, and Santiago is constantly identified with it and its creatures; his sea-colored eyes reflect both the sea's tranquillity and power, and its inhabitants are his brothers. Santiago refers to the sea as a woman, and the sea seems to represent the feminine complement to Santiago's masculinity. The sea might also be seen as the unconscious from which creative ideas are drawn.
