Adrian:

He is a lord attending King Alonso of Naples, and a minor character in the play. After the tempest, Adrian is washed ashore in company with Alonso and several other members of the king's court. His and Gonzalo's efforts to cheer up the dejected king in II.i are ridiculed by Antonio and the king's brother, Sebastian. Thus Adrian's optimism serves as a foil to Sebastian and Antonio's mean-spirited cynicism. (A foil is a person or thing that highlights another character's traits through contrast.) When Alonso, Sebastian, and Antonio are temporarily driven crazy by Prospero's spells, Adrian sorrowfully watches over them, along with Gonzalo and Francisco (III.iii.104-09; V.i.7-13).

Alonso:

He is the king of Naples and the father of Ferdinand. King Alonso, his son, and his courtiers get caught in the tempest on their way home from the marriage of his daughter to the...