Orestes is the son of Agamemnon and Clytemnestra. In the play, there was probably one actor who played him, while other parts were split between the other two speaking actors. It is also possible that the role was reprised by the actor who played Orestes in the previous part of the Oresteia trilogy, Libation Bearers, in which Orestes murdered his mother Clytemnestra and her lover Aegisthus in revenge for their murder of his father Agamemnon.

Though Orestes is in some ways the subject of Aeschylus’s Eumenides, his character remains relatively static throughout the play. He does not even have very many lines, and generally it is Apollo who speaks for him (such as during the murder trial at the Areopagus). The play begins with Orestes pursued by the Furies, goddesses of retribution who punish murderers. Orestes is supported by the god Apollo, who instructed Orestes to kill his father’s murderers. Throughout the play, Orestes defers obediently to Apollo, as when he seeks purification for his crime or when he goes to Athens to ask Athena for her help. During his trial, Orestes does not deny that he killed his mother. Having simply obeyed the orders of Apollo, he is perfectly assured of the justice of his actions, leaving it to Apollo to make his case for him.