Prometheus is a cross between a rebel archetype, a symbol of intelligence, and the personification of human progress. As a result, he experiences something like a split personality disorder, as rebellion slowly takes over from intellect and progress. In the first stage, Prometheus stands as the intellectual figure. He tells the Chorus that he will be reconciled with Zeus, restoring harmony to the universe, and he speaks of the importance of his guile, or intelligence, in Zeus's ascent to power. Two sides of Prometheus's intelligence are emphasized in this first section of the play. First, intelligence is seen as the attribute that tips the balance of power in favor of the side it is on. Prometheus's mother prophesied that the victor would be the side that uses guile. When the Titans rejected Prometheus's guile, he went to Zeus and triumphed. There is also a second side to intelligence: its role in maintaining the stability of the universe. Zeus will need Prometheus's knowledge and intelligence to save himself and maintain the present order. Prometheus thus prophesies that Zeus will come to him for help and the two of them will be reconciled, restoring a proper balance to the cosmos. At this early stage in his character development, Prometheus also shows fear and laments his fate, something that does not recur in later stages.
As Prometheus tells his story to the Oceanids, he slowly becomes angrier and more defiant. He removes emphasis from his reconciliation with Zeus and focuses on his own importance as a force of progress. Here Prometheus boasts of all the gifts he has given to humanity, insisting that he is responsible for all human arts and portraying himself as central to the growth of human civilization and the survival of the race. When Io appears, Prometheus tells her about the progress of her descendants. He also continues to demonstrate his own importance as he describes her previous travels in order to prove that he knows what he is talking about in his prophecies. Most significantly, his prophecies concerning his future relation to Zeus change. Prometheus now emphasizes first Zeus's downfall and then his own release. Only when prodded does he mention reconciliation as a possibility. Speaking of his release, he seems to imply that this will happen without Zeus's consent, clearly changing the tone of the prophesy from the first part, if not fully contradicting it. As part of the same trend, Prometheus repeatedly underscores the suffering Io has ahead of her while spending very little time on the description of her eventual salvation.
Io's visit clearly angers Prometheus as he recognizes the extent of Zeus's tyrannical injustice. Earlier he had attempted to reveal his prophecy only in pieces and somewhat reluctantly, but now he shouts it out loud. Also, Prometheus no longer seems to experience any sadness or fear. He urges Hermes on in bringing about further punishment. Importantly, the content of Prometheus's prophecy has changed completely. While earlier he prophesied two possibilities with an emphasis on reconciliation, now he ignores both reconciliation and his own liberation. The focus switches entirely to Zeus's downfall and Prometheus even provides a description of Zeus's destroyer. Here Prometheus as intellect and Prometheus as source of progress have been entirely replaced by the romanticized Prometheus as defiant rebel. He openly mocks Zeus and Hermes and refuses any possibility of reconciliation with a tyrant. Prometheus's inner change in the course of the play is thus brought out through three external cues. First, the content of his prophecy changes from favorable to himself to being simply unfavorable to Zeus. Second, his fluctuating fear and sadness disappear and are replaced by single-minded defiance. Finally, he moves from a state of concealing his knowledge to one of openly revealing what will most anger his enemies.
Zeus probably does not appear in the play because of rules forbidding the presentation on stage of the supreme god. Regardless of whether this is the actual reason, Zeus's absence contributes significantly to the image of him as it is developed throughout the play. First, this absence allows for Zeus to be represented by his servants, who leave an unfavorable impression. Kratus, Force, and Bia, Violence, convey some fairly obvious hints about Zeus through their names alone. Clearly the tyrant rules entirely through intimidation and punishment rather than cooperation and friendship. Stress is repeatedly placed on the idea that Zeus rules by his own laws and does not answer to anyone for what he does. As a result there are two possible ways to view Zeus's rule in relation to justice. Either he is simply not just, since he clearly does not follow any rules, or he is equivalent to justice because he sets the standards of right and wrong.
The possibility of Zeus creating his own and the only possible justice in the course of his rule leads us to a second important feature of Zeus's absence. He is allowed to be represented by servants who suggest that Zeus's law is the only possible law. Though this may seem reasonable since Zeus is the greatest of the gods, Aeschylus undermines our faith in Zeus as a just god by contrasting the total lack of pity in Zeus's servants with the sympathy experienced by Prometheus's friends. The suggestion is that right and wrong exist apart from Zeus and he, as a new ruler, has not yet learned this. This may be why the newness of Zeus's reign is repeatedly mentioned: it is to show that he has not yet fully adjusted to the role of just ruler, and the current lack of a fit between him and justice is responsible for the conflict between him and Prometheus.
Finally, we should note that Zeus's absence in the play adds to a feeling of isolation surrounding him. Not only is Zeus still removed from justice by the arbitrary nature of his laws, but also he seems removed from others. Since, as evidenced by his servants, Zeus demands complete obedience in body and mind, he can have slaves but cannot have friends. Zeus is left isolated from both Prometheus and the audience. The isolation reinforces the impressiveness of his power, which would be diminished if we were to see him. At the same time, however, this isolation makes Zeus look very lonely. We see this through a contrast with Prometheus, who closes the play in the company of his friends. Zeus's servants, on the other hand, never leave with friends. Kratus leaves with Hephaestus, who dislikes him, and with Bia, who doesn't talk. Hermes leaves all alone. Zeus's servants live entirely in his shadow. As far as we know, Zeus's character does not change in the course of the play. He certainly becomes concerned when he hears Prometheus's prophecy, but his servant at the end, Hermes, is just as arrogant and uncompromising as his servant at the beginning Kratus, so we may assume Zeus has not undergone any serious change.
The Chorus appears in this play as an interesting character in its own right, underscoring the conflict between the accepted value of obedience and the possibly higher value of friendship. The role of the chorus in a Greek tragedy is to uphold the moral standard. When Prometheus appears too rebellious or defiant, the Chorus clearly tells him that he would be wise to tone down his rhetoric. The Oceanids essentially uphold three positions. First, one must not rock the boat. The Greeks believed that a happy medium was always the ideal to strive for, so that the Chorus reprimands Prometheus for disrupting the harmony of the universe and the human/divine balance of power. Prometheus is too excessive and he should learn some moderation. Second, the Chorus teaches that one must remain pious and obedient. The Oceanids suggest that there is enough reason to fear Zeus to make one bow to him instead of defying his orders.
Finally, the Oceanids advise that one act prudently. Prudent action means not only that one should avoid angering a powerful and tyrannical Zeus, but also that one should not help those who cannot return the favor—this is prudence in its full form. So far all this is the normal role of the Chorus in a Greek tragedy. What makes this Chorus so interesting is the concluding deviation from all these moral teachings. Particularly, the Oceanids reject prudence and obedience as the main reasons for action and instead take up friendship. This is defiant because the action of staying with Prometheus contradicts divine orders. It is also imprudent since, the Chorus is helping a friend who cannot help back and because punishment here is not a possibility but a certainty. The Chorus's sudden reversal of the moral position it had been preaching is clearly significant. Friendship is a recurring theme throughout the play, often in accusations that Zeus does not trust his friends or hints that he doesn't really understand the concept. The Chorus, by deciding to honor friendship as the highest value, gives precedence to the view that friendship is a value superior to all others.