King Claudius is a fictional character and the main antagonist of William Shakespeare's tragedy Hamlet. He is the brother to King Hamlet, second husband to Gertrude and uncle and later stepfather to Prince Hamlet. He obtained the throne of Denmark by murdering his brother with poison and then marrying the late king's widow. He is loosely based on the Jutish chieftain Feng who appears in Chronicon Lethrense and in Saxo Grammaticus' Gesta Danorum. There has never been an actual Danish king of that name.

Prince Hamlet is the title character and protagonist of William Shakespeare's tragedy Hamlet (1599–1601). He is the Prince of Denmark, nephew to the usurping Claudius, and son of King Hamlet, the previous King of Denmark. At the beginning of the play, he is conflicted whether, and how, to avenge the murder of his father, and struggles with his own sanity along the way. By the end of the tragedy, Hamlet has caused the deaths of Polonius, Laertes, Claudius, and Rosencrantz and Guildenstern, two acquaintances of his from childhood. He is also indirectly involved in the deaths of his love Ophelia (drowning) and of his mother Gertrude.