The magician Prospero is the main character in the play, both as the focus as well as the orchestrator of all the action. As the duke of Milan Prospero was too focused on magical study and left the running of his dukedom to his brother Antonio, who eventually deposed him. Exiled to an island, Prospero and his daughter Miranda have lived in near isolation for 12 years. During that time Prospero has become a more powerful magician. When fate brings the men who conspired against him within reach, Prospero uses his powers to elevate his daughter's position in society and program revenge against his enemies, including the very brother who took his dukedom from him. In the end Prospero abandons his plan for vengeance and forgives his enemies of their offenses. He regains his dukedom and plans to return with his newly engaged daughter to Italy.
Prospero's faithful spirit servant, Ariel, helps execute Prospero's plans to gather his enemies on his island in order to repay them for their traitorous crimes against him. Ariel is still haunted by his former experience as a slave to the witch Sycorax but serves Prospero willingly, enticed by the promise of freedom, which Ariel receives at the end of the play. It is primarily Ariel's magic Prospero uses to manipulate the other characters throughout the play.
Exiled with her father when she was only three years old, Miranda has grown up on an island with no humans other than her father and their slave, Caliban. When she meets Ferdinand she is awed by his beauty and immediately falls in love. As she is exposed to more people, she cannot help but be amazed by all that humanity can be. Engaged to her beloved Ferdinand at the end of the play, she prepares to travel to Naples for their wedding. Miranda's name means "to wonder at or be admired," and she generally acts with wonder and admiration to most of what she sees, including the ship, Ferdinand, her father's explanation of how she came to live on the island, and the other nobles.
Son of the deceased witch, Sycorax, the half-human Caliban loses control of the island when Prospero and his daughter Miranda arrive there 12 years earlier. Although Prospero and his daughter try to educate Caliban in their language and ways and claim they treated him with respect and kindness at first, he later tried to rape Miranda. He is now a bitter, frequently punished slave. When Caliban meets some of the castaways from the ship, Trinculo and Stephano, he hopes to serve a new master. He soon realizes that the new master is worse than Prospero.
Alonso, the king of Naples, is onboard a ship returning to Italy from Africa, where his daughter has married the king of Algiers. After the shipwreck Alonso despairs over the presumed drowning of his son, Ferdinand. When Ariel reveals Alonso's part in the exile of Prospero, Alonso repents of his past sins. Buoyed by Prospero's forgiveness and overjoyed at his son's reappearance, Alonso celebrates over the coming marriage between Ferdinand and Miranda.
Gonzalo, King Alonso's advisor and Prospero's old and loyal friend, is the idealist in the play. When he sees the beauty and purity of the isolated island, he considers the utopia he might create there, eliminating poverty and wealth as well as social classes. Because he helped Prospero escape long ago, he has earned Prospero's gratitude.
Antonio is the current duke of Milan after undermining his brother Prospero's power and exiling him from his home 12 years before. A greedy and unsympathetic character, he blames King Alonso for the shipwreck and the supposed drowning of Ferdinand. He then plots with Sebastian, King Alonso's brother, to kill Alonso and take power. Though forgiven by his brother Prospero in the end, Antonio shows no remorse over any of his behavior.