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.