Aristotle's tragic hero is defined in Poetics and consists of five essential characteristics. Although some tragedies did not follow Aristotle's model, the list of characteristics that Aristotle describes became a prototype and outline for many Greek tragedy writers. Euripedes wrote over one hundred tragedies and many times he followed Aristotle's definition. Medea is unique in that it consists of many of Aristotle's ideas as well as some that Euripedes implemented himself.
Aristotle states that a tragic hero must be noble, which means that the hero must be of high social class possessing moral qualities as well as unique abilities. Medea was a princess of Colchis and displayed a vast knowledge of enchantments, medicine, and sorcery. Medea's moral qualities were removed only after her husband Jason had abandoned her and their two children and began courting the daughter of King Kreon of Corinth.
The fading of Medea's moral values was directly related to her hamartia, the second characteristic of Aristotle's tragic hero. Hamartia is a flaw or weakness in the hero and Medea's was her immense anger and wrath towards everyone around her, including herself, once she learned of Jason's betrayal. In her wrath she deceived Jason by gaining his confidence again only to bestow him gifts of malice such as a poisoned wedding gown that kills Kreon's daughter, as well as Kreon himself who is so heartbroken that he embraces his dead princess and absorbs the poison also. Included in her plot for vengeance was the murder of her own two children. The satisfaction of the pain she caused Jason by doing this far outweighed her own devastation.
Medea's slaying of her own children is part of the third characteristic of Aristotle's tragic hero. Her hubris, excessive pride, and desire for revenge led Medea to the loss of her children. Prior to this act she believes that killing them will hurt Jason more than her and that she will achieve fulfillment through her retributive justice.