Claudius: Claudius killed his brother, King Hamlet, in order to get the throne. This might sound bad but in the other hand, Claudius would never become the king because, prince Hamlet was the next to take the throne. Therefore, Claudius had to kill his brother because he would never have got the chance to become a king because he would get way to old and die.

Prince Hamlet: Prince Hamlet had the right to kill his uncle, Claudius, because he killed his father and he took his throne. Also, he married his mother, which Prince Hamlet loved.  Prince Hamlet was exile from Claudius’ kingdom, so he had the right to revenged his father and return to his land.