The highest-ranking official at the beginning of the play, he is its tragic hero. He is proud of his rank and accomplishments. Yet despite Agamemnon's leadership, he is less admired now by his subjects for fighting an unpopular war. He is portrayed as less intelligent and less forward thinking than his wife, believing prosperity will shield him from misfortune. Agamemnon attempts humility, saying he does not want to be treated as a god. But like other Greek tragic heroes, he is fatally flawed by hubris (pride).
Driven by the desire for vengeance and power, the shrewd, audacious Clytaemnestra is the play's most developed and complex character. She professes loyalty to Agamemnon and praises him at the same time as she plots his death. She also is argumentative, defending her thoughts and opinions to the Chorus when they disagree.
Cassandra, Agamemnon's war captive, is emotional and distraught by the destruction of her homeland. Given the gift of prophecy by Apollo, she can see accurately into the past, present, and future. However, after Cassandra refused to bear his child, Apollo cursed her so no one would believe these prophecies.
Like Clytaemnestra, Aegisthus wants power and vengeance and is led to murder by the need to avenge a wrong done to his family. His manner is authoritative and menacing. He wants to implement a strong, controlling government, threatening to enslave anyone who disagrees with him.
Because Chorus members represent citizens of Argos, they have a vested interest in the actions and may make moral pronouncements based on characters' decisions. Aeschylus gives Chorus members opinions and sympathies and occasionally individual lines, though with no impact on the outcome of the drama. As a group the Chorus is loyal to Agamemnon, leader of their city, but disagrees with his decision to go to war. Agamemnon's death deeply affects the Chorus.