How does the tragedy of julius caesar explore the theme of betrayal? as the tragic figure in the play, octavius’ involvement in caesar’s assassination, in which cassius murders his friend, eventually leads to his downfall. as the tragic figure in the play, mark antony’s involvement in caesar’s assassination, in which mark antony murders his friend, eventually leads to his downfall. as the tragic figure in the play, cassius’ involvement in caesar’s assassination, in which cassius murders his friend, eventually leads to his downfall. as the tragic figure in the play, brutus’ involvement in caesar’s assassination, in which brutus murders his friend, eventually leads to his downfall.