Even though he spends almost the whole play chained to a rock in the Scythian wilderness, Prometheus is still definitely the protagonist of this play. Even before the beginning of the play, he started the whole action by stealing fire from the gods and giving it to humans. Ever since then, he seems to be the one guy that everybody else in the universe can't get enough of. Even Io, who has been transformed into a cow and is tormented by a gadfly that keeps biting her, can't help asking Prometheus to tell his story. He's just so fascinating.