Berenger's transformation is the true metamorphosis in Rhinoceros. While the other characters physically turn into rhinoceroses, embodying the savage natures they had formerly repressed, Berenger's change is moral and completely opposite from his position at the start of the play. He begins as an aimless, alienated Everyman who drinks too much and who finds little worth in life, except for the beauty of Daisy, his co-worker. He is bored by his work, too lazy to culture himself, and wonders if life is a dream—that is, if its absurdity is the product of a dream-like state of absurd logic, and if life, like a dream, is controlled by unconscious desires. Despite his escapism through alcohol, he holds on tightly to his human identity, never comprehending why someone would want to be anyone else. While his passivity is the underlying cause of the metamorphoses, helping promote the climate of irresponsibility and indifference, it is his recognition of life as an absurdity that prompts him to change his character, rather than accept the presence of the rhinos. Yet he remains indecisive nearly to the very end, losing his faith in humanity and finding the rhinoceroses beautiful. In the last line of the play, however, he overturns his weak will and lack of responsibility by deciding to save humanity against the tyranny of the rhinos.
Berenger's decision, however, is not totally unforeseen. His love of Daisy, as mentioned above, reveals he has emotional desires for another human. At one point, when it seems to him that he and Daisy will be united at the expense of their co-worker Dudard's departure and metamorphosis, Berenger exclaims "Happiness is such an egotistical thing!" Yet his desires turn out not to be so self-centered. Even when Daisy abandons him to become a rhino, and when other friends insult him and do the same, he feels guilty for pushing them out, although they would have metamorphosed without him. He does not love Daisy alone; he loves humanity, and is willing to take responsibility for its fate. This "will" of responsibility, rather than the will of power the other characters treasure, is what ultimately galvanizes Berenger's final line of resistance, "I'm not capitulating!"
Jean epitomizes the Nietzschean conception of the "super-man" who is above morality. He believes in the strength of his will and rationalist intellect. His arrogance and unspoken disdain for the common man, especially for Berenger's lackadaisical attitude toward life, foreshadows his metamorphosis into a savage, vicious rhinoceros. As the most fleshed-out character who transforms into a rhino, he symbolizes the Nietzschean "will to power" of the fascist rhinos, their use of strength and will to circumvent morality and return to a primal state of nature. Yet Jean is ridden with hypocrisies and contradictions. He shows himself from the start to be as irresponsible as Berenger, showing up late to their meeting and refusing a day of culture to nap and drink. In fact, his appreciation for self-improvement seems to stem from his view of education as cultural capital, and not as an exploration of his humanity. He always rationalizes these lapses after the fact, drawing on his vast reserves of logic to skew the discussion. When Jean vows, as a rhino, that he will trample Berenger and anyone who gets in his way, it is clear that his transformation was a mere exchange of bodies, and not of morality.
Though they are not human characters, and they never appear on-stage in full form, the projections of rhino heads and off-stage trumpeting dominates the play. The rhinoceroses stand, above all, for man's latent savagery and capacity for violence. The rhinos themselves are not to blame; they are generally a solitary species, as Berenger notes, but the collective consciousness of man and the tendency toward safety in numbers turns them into a hostile, totalitarian herd reminiscent of Nazis. Nevertheless, Ionesco makes sure to flesh out the rhinoceroses' characterizations. When Mr. Boeuf turns into a rhino, he trumpets tenderly to his wife, who can recognize her husband through his green skin. Not all of Boeuf's humanity is lost, and it appears that the individual man affects the characteristics of the rhino he becomes. To nuance their depictions even more, Ionesco has the rhinos become more beautiful and majestic as the play progresses until, by the end of the play, they outshine the ugliness of humanity. This technique makes the audience see how one's individual perceptions can be altered by mass opinion, how the savage, destructive rhinos, much like the Nazis, could be seductive to someone who doubts his own strength and will.
Although he appears only in the first act, the Logician, as his name suggests, represents the other rationalist characters (Jean, Botard, Dudard) and one of the underlying premises of the play and existentialist philosophy, that logic cannot explain everything. In fact, Ionesco severely mocks the Logician's circular, comic train of thought, which focuses on all the wrong questions and ends up with completely incorrect answers or answers that re-pose the original question. We must recognize the universe as absurd and nonsensical, Ionesco believes, in order to take any meaning from it; the Logician and other characters resist this, though they often succeed only in proving themselves absurd.
Daisy appears as if she, along with Berenger, cares deeply about humanity, but she continually urges Berenger to acclimate himself and not to feel guilty about the rhinoceroses. Her love for him appears as an ephemeral desire that flickers on and off, and in the end love for only one person does not necessarily make one into a truly loving person. In order to commit one's life to something outside oneself, as the existentialists were concerned with, one must love all humanity. Daisy's constant avoidance of responsibility and her lack of concern for her fellow man reveals her desires for Berenger as selfish despite the good intentions she often has for him (she tries to limit his alcohol intake, for instance, and wants to assuage his guilt to make him happier). Understandably, she is seduced by the beauty and power of the rhinos, something that offers her greater pleasure than the "weakness" of human love, as she puts it. Her final betrayal of Berenger in joining the rhinos incites his dramatic decision to save humanity; it is his love for her (and the loss of it) that makes him feel guilty and responsible and which allows him to see how much he loves humanity, and not a single person, after all.