These works that you are reading, the Theban cycle, are all tragedies. So, you will find a lot of tragic figures in all of them. A figure is a tragic one, because of some great quality, which leads to hubris (pride). The average person cannot be tragic, because they are too ordinary. Only the great can be tragic. In my opinion, the Greeks were masters at problematizing two or more important virtues. For example, loyalty to brother or loyalty to father. Or love for city or love for family. Or commitment to justice or commitment to compassion. I think you get the point. In the end, a person has to chose one and therefore not the other; hence the person becomes tragic. From this structural framework, Creon and Antigone (more so) fit this pattern. Antigone has to choose - whatever decision she makes will make her compromise something. For this reason, she will be tragic.
Yes, it is possible, but you do have more than one option because both Antigone and Creon demonstrate most of the qualities of a tragic hero. In my opinion, Creon fits the title better, but you can make a sound argument for either character. Here's how:
1. Once noble hero/heroine experiencing a tragic downfall--Antigone is the daughter of royalty. As Oedipus's daughter, she is part of the Greek elite and is engaged to the new king's (Creon) son Haemon. She goes from this high position to being imprisoned, sentence to death, and committing suicide.
2. Tragic flaw--for Antigone, most would argue that her tragic flaw is pride--not necessarily in a negative sense but in doing what she knows is right in the gods' eyes and not wavering from that decision. However, she does demonstrate some arrogance in her attitude toward Ismene and Creon.
3. Tragic realization--when Antigone is led away and discusses her lonely fate with the Choragos, she realizes that she is going to have to sacrifice her life for her morals. Although she does not believe (or realize) that she has done anything to bring about her own downfall, she does question the unfairness of her situation and even becomes argumentative with the Choragos. Her realization is ultimately that she is going to die for her attempt to obey the gods, and she takes her own life in acceptance of that fate.
1. Tragic downfall: At the play's beginning, Creon is the newly crowned king. He seeks to bring order back to his city and punish those who created disorder. At first, he seems to have an opportunity to be a good king, but he makes foolish decisions based on arrogance and loses everything in the end.
2. Tragic flaw: Creon's tragic flaw is arrogance/pride. Teiresias, the prophet, even points out the danger of men being too proud. Creon will not listen to wise council or even to his own family members who try to dissuade him from executing Antigone--he wants to make an example out of her. In the end Creon's pride causes him to lose not only his niece but also his son and wife.
3. Tragic realization: Creon fits the role of tragic hero slightly better than Antigone does because of his extensive realization at the play's end. He considers killing himself because of the deaths that he has caused but realizes that that would be taking the easy way out. His realization occurs when he takes full responsibility for his decisions and admits that he should have tried to spare Antigone's life.
Good luck on your paper.
I like Northrop Frye's definition of a tragic hero best:
Tragic heroes are so much the highest point in their human landscape that they seem the inevitable conductors of the power about them, great trees more likely to be struck by lightening than a clump of grass. Conductors may of course be instruments as well as victims of the divine lightening.
Creon definitely fits this definition. As King, he is the highest point in the human landscape. He is struck by divine lightning and made to suffer: he wishes for death by the play's end. More, he makes others suffer: his son, wife, and potential daughter-in-law all die.
Does Antigone fit this definition? I think so. She doesn't qualify as much as Creon, but her passions are so extreme that she fits the definition. She is such a modern outspoken woman, a tall tree certainly in comparison to her deferential sister. In fact, it is her tragic flaw, her extremism and death wish, that may have incited Creon's. One tragic flaw leads to another, to be sure.