Rosencrantz and Guildenstern

Classmates of Hamlet in Wittenburg and were summoned by Claudius to spy on Hamlet and give him information. In the third act they are following the kings orders and the king gave a letter that asks them to execute Hamlet. They were only thinking about if they should kill Hamlet or not, in the end they didn't proceed with it but Hamlet reads the letter and finds out of their betrayal.