Ismene

About

In Greek mythology, Ismene was a Theban princess. She was the daughter and half-sister of Oedipus, king of Thebes, daughter and granddaughter of Jocasta, and sister of Antigone, Eteocles, and Polynices. She appears in several tragic plays of Sophocles, including Oedipus Rex, Oedipus at Colonus, and Antigone. She also appears at the end of Aeschylus' Seven Against Thebes.

Summary from Wikipedia