Jupiter is Orestes's most obvious opponent. He creates the moral systems intended to order human action. By inspiring fear in his subjects and by showing them signs, Jupiter hopes to force them to act in the way he wants. There is only one flaw in this design: Jupiter can't actually force anyone to do anything. Only human beings can decide whether or not they will follow Jupiter's wishes; his goal, then, is to make sure that they do not realize that they have this freedom to decide for themselves. Since Orestes is the only person in the play who understands what it means to be free, i.e., to have the ability to choose for oneself instead of doing what one is told, he is the clearest threat to Jupiter's reign. Jupiter's character does not develop in the course of the play. Because he is a god rather than a human being, he does not have the ability to change over time. Jupiter is not really a person: he is an image that people keep in their minds. He must always present the same image of himself to human beings: the image of a supreme judge to be feared and obeyed.
The character of Jupiter stands for all systems of political or moral authority. By forcing rules for action onto people, these systems attempt to deprive human beings of their power to act freely. Sartre cleverly interprets farce and melodrama into his presentation of Jupiter. Jupiter's tricks of making flies fall down and his ability to move stones appear fairly silly: he raises his arm and speaks nonsense. Sartre wants us to realize that institutions that seek to limit human freedom are only images that maintain their power because human beings believe in them. What lies behind the image isn't power at all; the power is contained in the value we ourselves assign to the image. The comical way in which Jupiter carries out his magic tricks and the melodrama with which he gives his orders show us one thing: what lies behind all moral domination is farce.