Electra turns out to be Orestes's foil. Her development closely parallels his, but in the opposite direction. When they first meet, Orestes has no intention of doing anything in Argos; he plans to leave and wants to take her with him. Electra, on the other hand, has lived for years with the belief that she has a destiny that she must fulfill: she must avenge her father's death. This acceptance of her destiny is, in the end, her downfall. Her destiny is a fantasy. It gives her meaning and purpose in life. Consequently, when her destiny is carried out, Electra has nothing to live for. Unlike Orestes, she cannot define herself through her action because she only knows how to define herself through her destiny—an outside force telling her what to do. Revenge was the one thing that made her life meaningful, so once revenge is no longer something she can look forward to, her life loses meaning.
Before the murder, Electra is confident that to carry it out is the right thing to do. Revenge is what she values most in life. With the action completed, however, Electra sinks into cowardice. She lacks the courage of her earlier beliefs since, paradoxically, what gave those beliefs power was the fact that she had not acted on them. Once her hatred is gone and her life has no meaning, her value system dissolves. Since revenge is no longer a key value for her, she is forced to turn to others for values, and she realizes that others would judge her as a killer. Because Electra no longer has a value system of her own based on which she can claim she did the right thing, she must accept the external value system that tells her that she did the wrong thing. Electra therefore repents of the murder, leaving Orestes alone in the certainty that it was the right action.