Medea
Medea is the protagonist and the engine of the play. She's brilliant, dangerous, and completely cornered. Euripides writes her as someone capable of enormous love and enormous destruction, and the play shows how one turned into the other. She plans every step of her revenge with precision and carries it out even when it costs her everything.
Jason
Jason is the antagonist, though he never sees himself that way. He abandoned Medea for a politically useful marriage and genuinely believes his reasoning is sound. The play uses him to show how self-serving logic can cause catastrophic harm. He ends the play with nothing, which is exactly what Medea intended.
Creon
Creon is the king of Corinth who orders Medea's banishment. He's afraid of her and says so openly. His decision to give her one extra day when she asks is the mistake that makes everything possible. He dies because of it.
The Nurse
The Nurse opens the play and sets the tone. She loves Medea and fears her in equal measure. She functions as a moral compass for the audience, someone who understands Medea's pain but dreads what it might produce.
Aegeus
Aegeus is the king of Athens who appears briefly and promises Medea sanctuary. His appearance is sometimes criticized as convenient, but it matters structurally: it gives Medea an escape route, which frees her to act without worrying about what comes after.
The Chorus
The Chorus is made up of Corinthian women who sympathize with Medea, at least at first. They listen, react, and comment on the action. As Medea's plan becomes clear, their sympathy shifts to horror. They represent the audience's changing response to Medea in real time.
Glauce
Glauce is Jason's new bride and Creon's daughter. She never speaks in the play. She exists as the target of Medea's revenge and dies horribly from the poisoned gifts. Her silence makes her a symbol of the collateral damage Jason's choices produce.