In The Tempest, Prospero’s primary goals are to match his daughter, Miranda, with Alonso’s son, Ferdinand, and thereby to unite the dukedom of Milan with the kingdom of Napes, which Alonso rules. That is the reason he has diverted the ship carrying the Italians to wreck on his island. Fortunately Miranda and Ferdinand like each other right away and are soon “in either’s powers” and their love endures, which Prospero had feared it might not. If he did not forgive the betrayal, the union could not be accomplished; instead, there would probably be war.
Other than his brother, who betrayed him and usurped his dukedom, and the complicit Alonso, it is debatable who Prospero’s “foes” are. He has a tendency to take things over, and on the island he has used magic to make others his servants or even slaves. He attributes his antipathy toward Caliban is to attempted rape of Miranda. Caliban’s fate remains unresolved at the play’s end.