Ismene is Antigone Lite. She first puts in an appearance along with her sister at the end of Oedipus the King. Both girls seem to be symbolic of the legacy of shame left by Oedipus's mistakes. In Oedipus at Colonus, Ismene shows great loyalty to her father when she alerts him to the situation with Creon. She shows devotion once more when she returns with Antigone to Thebes. In Antigone, however, we see that Ismene's loyalty only extends so far. Though she agrees morally with Antigone’s decision to bury Polyneices, she is afraid to risk her own life.
Like her sister, Ismene seems to value family ties and the laws of the gods over the laws of man. However, she's just not gutsy enough to stand up for her beliefs. The courage to stand beside her sister does eventually come to Ismene. When Creon arrests both daughters of Oedipus, Ismene asks that she be executed alongside Antigone. Antigone, however, scorns Ismene's belated attempt at righteousness. At the urging of the Chorus, Creon eventually relents on executing Ismene. The girl ends the play with her life intact, but her self-worth in shreds.
Before we close the book on Ismene, we'd just like to recognize that the strong will that her sister is often praised for is also the thing that causes three suicides. If Antigone were a bit more like her sister, this wouldn't be a tragedy at all. Ismene's argument at the beginning of the play is that their family has suffered enough. What's the point of bringing more sorrow? Antigone and Ismene have had to live with the stigma Oedipus's horrific mistakes their whole lives. To top it all off, their two beloved brothers have just murdered each other. We can see Ismene's point. Is Ismene really that bad for just wanting to finally live in peace?