Orestes is the play's protagonist and only major human character. He struggles to carry out his duties as a son and family member, caught between conflicting forces. He wants to do the right thing—please the gods, bring justice to his family, and protect his home city of Argos. Yet he can't please everyone. During the trial he seeks confirmation that he committed a righteous act by killing his mother, though he doesn't regret the deed. As an exile from Argos he also longs to return home. As a human facing the consequences of his actions, Orestes functions as a relatable character for the audience.
Athena is perhaps the most powerful character in the play. She's a younger goddess than the Furies with less divine authority. But on her home turf in Athens, she makes the decisions. She and her court represent a new moderate, nuanced way of deciding criminal cases. Athena strikes a balance between the two opposing forces in the play, the Furies' primal desire for revenge and Apollo's desire for reason. Even though she is a female, she possesses many character traits associated with men in ancient Greece, like political power and leadership skill.
Like Athena, Apollo represents the newer, younger gods, more interested in looking toward the future than preserving the past. As the sun god he also represents light and knowledge, in contrast to the Furies' darkness and instinct. He commanded Orestes to avenge his father and serves as Orestes's main witness in the trial. Apollo, like many Greek gods in drama, shows human characteristics. He's temperamental, opinionated, and sometimes underhanded. But he's loyal to those he protects.
The evolution of the Chorus from vengeful creatures of the night to honored leaders in a new democracy is one of the play's major plot points. Their choral odes reflect on the roles of the old gods in maintaining universal order. Like a typical Greek Chorus they tackle the themes of pride, suffering, virtue, and human relations with the gods. But they differ from a typical Chorus in their character transformation and integration into the dramatic arc.