Aegisthus to Agamemnon and Clytemnestra
Aegisthus is the foil for both Agamemnon and Clytemnestra. He is the foil for Agamemnon because he provides a contrast to Agamemnon's outgoing, warlike nature. Instead, Aegisthus stayed at home and started an affair with Agamemnon's wife. But Aegisthus is also a foil for Clytemnestra, because he is more hot-headed than she is (like in his final confrontation with the Chorus), and he seems much less intelligent. In the eyes of the Chorus, Clytemnestra is bewildering and terrifying. In contrast, they see Aegisthus as mainly worthy of contempt.