As one of Oedipus’s four children, Ismene plays a role in each installment of the Oedipus trilogy. Unlike her sister Antigone, however, Ismene remains rather separated from the action throughout. She functions as a supporting character, delivering information and inadvertently highlighting the attributes of others, rather than someone who actively shapes the arc of the plot. In Oedipus Rex, Ismene appears onstage alongside her sister at the end of the play, weeping over the suffering that their father’s actions have caused. Although she does not have any lines, this moment allows Sophocles to further develop Oedipus’s character. His embrace of Antigone and Ismene emphasizes his overwhelming feeling of regret, both for himself and his daughters. The cost of his actions is even greater because they will inevitably influence the futures of his children. Ismene plays a slightly larger role in Oedipus at Colonus, but she continues to remain on the periphery of the action. She meets Oedipus and Antigone in Colonus and delivers important news from the oracles about her father’s fate and the growing dispute between Polyneices and Eteocles. In addition to establishing the play’s central conflict for the audience, Ismene’s role as a messenger highlights her commitment to serving her family. She may take a different approach than Antigone, who travels alongside Oedipus as a guide, but she nevertheless aims to take care of her father.
The details of Ismene’s character become even more clear in Antigone, the final play of the trilogy. She may only appear in two scenes, but the distinct perspective that she brings works to complicate the plot and highlights Antigone’s defiant attitude. When Antigone insists on burying Polyneices despite Creon’s orders, Ismene tries to talk her out of it. Her unwillingness to break state law in order to honor her brother suggests that there is a limit to her support for family. Arguing that they have already suffered enough, Ismene does not want to cause any more trouble by challenging authority. This perspective emphasizes her submissive nature and illustrates what she believes her role as a woman should be. Ismene is comfortable with her identity as a caretaker and seems to have no desire to act on her own behalf. This attitude, of course, contrasts with Antigone’s worldview and makes her actions appear even more bold and courageous. As Creon seeks to punish Antigone for treason, Ismene returns with a new perspective and begs to share the guilt with her sister. This shift, which Antigone refuses to accept, may seem selfless, but Ismene’s lament of a life without her sister implies that there may be selfish undertones to it. She ultimately survives the play as a result of her initial unwillingness to act, leaving her entirely alone.