Prospero
The rightful Duke of Milan, though his kingdom and title were usurped by his brother Antonio. Prospero was able to survive a plot on his life, and he and his daughter Miranda were set aboard a wrecked craft, but managed to land safely on the island. Prospero is able to gain control of the spirits of the island, and uses his vast knowledge and control over the spirits to direct acts of magic as he pleases. He is ruler of the island, after taking control of it from its rightful heir, Caliban, and he makes sure that Alonso's ship wrecks on the island, so he can get his revenge on his brothers for their wrongdoing.
Alonso, King of Naples
Was involved in a plot to overthrow Prospero, and gave Prospero's dukedom to Antonio. Has a son, Ferdinand, who is also heir to the kingdom. Alonso may have been corrupt in his dealings with his brothers, but he does not prove to be an evil-natured man; he is a flawed politician, but is a highly regarded king and is not a villain.
Sebastian
Brother to Alonso, Sebastian is easily infected by a plot for the crown made by Antonio, and impressed upon him by the magic of the spirit Ariel. He is also not evil, but has a flawed nature.
Antonio
Usurped the dukedom of Milan from his brother Prospero, while Prospero was absorbed in study. Antonio is probably the least scrupulous character in the play, and he is the originator of another plot to take the throne from Alonso through more murdersthough this plot is engineered by Prospero, and made possible by Ariel's magical powers. He is typically sarcastic and remote, and unrepentant of his crimes.
Miranda
Prospero's only daughter, and so young that she cannot remember anyone she knew before she came to the island. She is intelligent and headstrong, having learned a lot from her father; but, when under Ariel's enchantment, she follows her father's plan, and falls in love with Ferdinand willingly. She and Ferdinand end up together, bound by their mutual infatuation.
Ferdinand
Alonso's son, and heir to the kingdom of Naples. Prospero arranges, through his magic, for Ferdinand to fall in love with Prospero's daughter, Miranda; Prospero's plot to have Miranda and Ferdinand married is his key to reclaiming his power in Italy. For the brief span of the play, Ferdinand is completely lovelorn and presumed dead by his father because they are separated during the shipwreck; out of his infatuation with Miranda, he agrees to become Prospero's servant for a span. Prospero finally declares him worthy, and the engagement is at last approved by both Prospero and Alonso.
Ariel
A spirit of the island, over whom Prospero becomes master after ousting Sycorax. He is the source of Prospero's magical powers, causing the tempest and many of the conspiracies in the play, and works for Prospero somewhat against his will. He is an intelligent, capable servant, and is finally freed by Prospero for his devoted service.
Gonzalo
The councilor to the king, and an honest man as well; he is the one who helps Prospero and Miranda survive Antonio's plot to have them murdered. Gonzalo is optimistic, good-tempered, and loyal; he is one of the unquestionably good characters in the play, with no apparent dark side in him.
Adrian and Francisco
Noblemen, and companions of Alonso who are shipwrecked with the rest. Adrian tries his best to console Alonso when Alonso believes that his son is dead; and Francisco also tries to be helpful to the king. Neither play a very important role within the play, but they do appear to be good-tempered men, and Adrian at least is taunted by the very sarcastic pair of Antonio and Sebastian.
Caliban
A native of the island on which Prospero lands, and the one from whom Prospero steals control of the island. He becomes Prospero's only subject, doing all of his dirty work; Caliban tries to rape Miranda, and is shunned by both Miranda and Prospero because of this. All who encounter Caliban regard him as sub-human, or reprehensible, because of his different looks and strange ways. However, Caliban has a capacity for poetry and understanding beauty, as shown by a speech in Act III, which is one of the most poetic, beautiful, and descriptive of the play. Gonzalo is the only one within the play who even tries to evaluate Caliban and his kind fairly; the others, blinded by prejudice, mistreat him to various extents.
Trinculo
A consistently drunken jester, who is a servant of Alonso's, and brought ashore in the shipwreck. He is a dull fool mostly, not capable of any real action, and providing a good deal of comic relief. When Caliban meets him, he immediately dislikes him and his inebriated insults; but, Trinculo does become a part of Caliban's plan to murder Prospero and take over the island, though Trinculo proves completely ineffective in this.
Stephano
Trinculo's friend, a consistently drunken butler. He is jolly, inebriated, and somehow Caliban takes him on as a new master, thinking that he has some magical powers. He agrees to Caliban's plot to make him ruler of the island, and gain him the favors of Miranda. However, like Trinculo, he is not cunning, and is completely incapable of carrying out the plan.
Master of a Ship, Mariners
Appear only in Act 1, scene 1. The master tries to hearten the sailors, and get them to sail the boat through the storm; but, one of Ariel's spells makes them lose heart and abandon ship. They are whisked safely away, and will take the party back to Italy at the play's end.
Boatswain
Right hand to the ship master, in control of the workings of the ship. Antonio and Sebastian try their best to pick a fight with him in the first act, and basically keep him from doing his job. The boatswain reappears in the last act, and tells about what happened to the ship's crew after the tempest.
Iris, Ceres, Juno, Nymphs, Reapers
Figures that appear in Prospero's betrothal masque for Miranda and Ferdinand in Act IV. Iris, Ceres, and Juno are goddesses from Roman myth; Iris is goddess of the rainbow, Ceres presides over agriculture, and Juno is queen of the gods. The parts are all performed by spirits, with Ariel performing the part of Ceres.
