The play's title character is its protagonist, though an inconsistent one He disappears in Act IV, seemingly replaced by Mosca, and is first an instrument and then a victim of Jonson's satire of money-obsessed society. He is an instrument of it because it is through his ingenuity and cleverness that Voltore, Corbaccio, and Corvino are duped and he seems to share in Jonson's satiric interpretation of the events, observing in I.v "What a rare punishment / Is avarice to itself." But the satire eventually turns back on him, when he becomes a victim of Mosca's "Fox-trap." The reason he is ensnared by Mosca is that he cannot resist one final gloat at his dupes, oblivious to the fact that in doing so, he hands over his entire estate to Mosca. This lack of rational forethought and commitment to his own sensual impulses, is characteristic of Volpone. He enjoys entertainment, banquets, feasts, and love- making. He hates having to make money through honest labour or cold, heartless banking, but he loves making it in clever, deceitful ways, especially as a means toward food and lovemaking. He is a creature of passion, an imaginative hedonist continually looking to find and attain new forms of pleasure, whatever the consequences may be. This dynamic in his character shapes our reaction to him throughout the play. At times, this hedonism seems fun, engaging, entertaining, and even morally valuable, such as when he is engaged in the con on his fortune hunters. But his attempted seduction of Celia reveals a darker side to his hedonism when it becomes an attempted rape. The incident makes him, in the moral universe of the play, a worthy target for satire, which is what he becomes in Act V, when because of his lack of restraint he ends up on his way to prison, the most unpleasurable situation imaginable.
In a play that revolves around disguises, Mosca is the ultimate master of disguise. He is the person who continually executes Volpone's ideas and the one who comes up with the necessary lie whenever needed. The lie could be made in order to save Volpone from the charges laid against him by Bonario and Celia or to convince Corvino to let his wife sleep with the Fox—either way Mosca seems to have no scruples about deceit. But his most important deception is the one he effects on Volpone and the audience, hiding his true nature and intentions from both the Fox and us. In the opening acts, Mosca appears to be exactly what he is described as: a clinging, servile parasite, who only exists for Volpone and through Volpone. In other words, he exists to serve Volpone, and all that Volpone wants he wants. This impression is reinforced by several cringing speeches that he gives, all in praise of Volpone. But in Act Three, we have the beginning of what seems an assertion of self-identity by Mosca, when he begins to grow confident in his abilities. But then this confidence again is left unvoiced, and Mosca seems to go back to being Volpone's faithful servant, helping him get out of the troublesome situation with Bonario and Celia. But it turns out that Mosca's aid in this situation may have been motivated as much by personal interest as it was by a desire to aid Volpone, for when he is presented with an opportunity to seize Volpone's wealth, he takes it. Mosca himself is possessed by greed, and he attempts to move out of his role as parasite—a harmless fly, circling around a great beast—to the role of great beast himself. But his attempt fails, as Volpone exposes them both. An interesting question is what significance his failure has in the context of the play and whether it is just punishment for his greed, his deceit, or his attempt to usurp the powers and privileges of the nobility and move above his social class.
While Volpone says "yes" to every single pleasure he can find—and pursues those pleasures vigorously—Celia is defined by her self-denial. This makes her a perfect foil for Volpone, since her self-restraint exposes his complete lack thereof, no more clearly than in Volpone's attempted seduction of her. The turning point of the play comes when she says "no" to Volpone's advances, thus denying him the lascivious pleasures he describes in his seduction speech. Celia seems willing to do anything to avoid dishonor, and this makes her character flat and predictable, too ready to sacrifice herself to be believable. Her willingness to subject herself to Corvino's harsh dictates and abuse may make her seem more weak than strong. But she has an inner moral sense, (even if it is dictated by seventeenth-century conventions on femininity) indicated by the fact that she refuses Volpone against her husband's express wishes. The fact that Jonson sides with her can be seen in his decision to put one of the strongest statements of the play's thesis in her mouth: "Whither, whither / Is shame fled human breasts? Is that, which ever was a cause for life , /Now placed beneath the basest circumstance? / And modesty an exile made, for money?" Jonson again chooses a name with symbolic meaning for Celia: it derives from the Latin word caelum, meaning "sky" or "heaven".
Voltore is, like all the legacy hunters, named after a carrion-bird. In the case of Voltore, that bird is the vulture; for Corvino, it is the crow, and for Corbaccio, the raven. Voltore is the most pleasant of all the legacy hunters, for he is the least crass and the least obsessed with seeing Volpone die. His preferential status shows in Mosca's special regard for him: Mosca tries to make sure that Voltore gets enough payment for his services at the Scrutineo in Act IV. But Voltore comes to regret his actions at the Scrutineo. Of course, this regret only comes after he has been denied his inheritance, and it seems to stem directly from his resentment at Mosca's leapfrogging over him on the social ladder. And when Volpone whispers to him that he might still get his inheritance, he stops confessing his lies to the Scrutineo and pretends that he was "possessed" by an evil demon. The verbal irony is that Voltore, in that statement and action, reveals his greed.