The role of the chorus

actors

usually part of the action, portraying local townsfolk e.g. in the Bacchae they are asian followers of Dionysus

scene-setting

choral song sometimes gave the audience important background information

commentator

offered a commentry or moral opinions on the events of the play.

background mood

background setting to the action, acting much like a soundtrack to the film. e.g. in Oedipus the chorus sing a joyful song before the climax

scene-break

create a break between scenes, acting as a stage curtain