Shakespeare uses the characters of Rosencrantz and Guildenstern to develop the theme that things are not always what they seem.
When Hamlet meets two of his friends Rosencrantz and Guildenstern he discloses his state of melancholy in which he has lost all the joys of his life and how his life seems worthless to him. They have been called by Gertrude and Claudius to help Hamlet come out of his state of mental stress. Though they were friends of Hamlet but worked under the guidance of Claudius by keeping an eye on Hamlet.
