His character is one of the few Shakespearean figures to take on a life of its own "outside" Shakespeare's own work: as Russell Hoban put it, "Caliban is one of the hungry ideas, he's always looking for someone to word him into being ... Caliban is a necessary idea".
Half human, half monster, after his island becomes occupied by Prospero and his daughter Miranda, Caliban is forced into servitude. While he is referred to as a calvaluna or mooncalf, a freckled monster, he is the only human inhabitant of the island that is otherwise "not honour'd with a human shape" (Prospero, I.2.283). In some traditions he is depicted as a wild man, or a deformed man, or a beast man, or sometimes a mix of fish and man, a dwarf or even a tortoise.
Banished from Algiers, Sycorax was left on the isle, pregnant with Caliban, and died before Prospero's arrival. Caliban, despite his inhuman nature, clearly loved and worshipped his mother, referring to Setebos as his mother's god, and appealing to her powers against Prospero. Prospero explains his harsh treatment of Caliban by claiming that after initially befriending him, Caliban attempted to rape Miranda. Caliban confirms this gleefully, saying that if he had not been stopped he would have peopled the island with a race of Calibans -- "Thou didst prevent me, I had peopled else this isle with Calibans" (Act I:ii). Prospero then entraps Caliban and torments him with harmful magic if Caliban does not obey his orders. Resentful of Prospero, Caliban takes Stephano, one of the shipwrecked servants, as a god and as his new master. Caliban learns that Stephano is neither a god nor Prospero's equal in the conclusion of the play, however, and Caliban agrees to obey Prospero again.
Despite this portrayal, Caliban also has moments in which he delivers memorable speeches, such as in Act 3, Scene 2:
Be not afeard; the isle is full of noises
Sounds, and sweet airs, that give delight and hurt not.
Sometimes a thousand twangling instruments
Will hum about mine ears; and sometime voices
That, if I then had waked after long sleep,
Will make me sleep again; and then in dreaming,
The clouds me thought would open, and show riches
Ready to drop upon me, that when I waked
I cried to dream again.
The later twentieth century saw the image of Caliban serving as a focus for thinking about the colonial and postcolonial situations. Since Prospero and Caliban (1954) by Oscar Mannoni, Caliban has been seen as a symbol of the colonial oppressed, both in productions of The Tempest and in adaptations: thus for example Caliban is the protagonist of Aimé Césaire's 1969 play A Tempest, in which he is a black slave in rebellion against his white master Prospero.
There is some disagreement though. Caliban's mother, Sycorax, came from Algiers originally, not the island. Therefore, it has been argued that Sycorax was a colonizer who oppressed the rightful inhabitants, Ariel and his people.
While some 21st century critics have come to see this as an outdated allegory, considerations of race, status and even gender continue to affect the casting of Caliban in modern productions.
There is a long history of enthusiastic speculation on the name's origin or derivation.
One of the most prominent suggestions concerns Caliban being an anagram of the Spanish word canibal (Carib people), the source of cannibal in English. The character may be seen as a satire on "Noble cannibal" from Montaigne's Essays (A.30, "Of Cannibals").
Also popular has been comparison to kaliban or cauliban in the Romani language, which mean black or with blackness. The first Romanichal had arrived in England a century before Shakespeare's time.
Many other, though less notable, suggestions have been made, primarily in the 19th century, including an Arabic word for "vile dog", a Hindu Kalee-ban "satyr of Kalee, the Hindoo Proserpine", German Kabeljau ("codfish"), etc.
In the film Clash of the Titans, the main antagonist is a character based on Caliban named Kalibos, the evil son of the sea goddess Thetis, transformed by Zeus from a handsome man into a monster as punishment for his malevolence.
In the 1956 science fiction film Forbidden Planet, Caliban is re-imagined as "the Monster from the Id", a wild and violent monster that is invisible to the naked eye. The monster later turns out to be born of the subconscious of the film's Prospero character, Dr. Morbius, using the advanced technology of the Krell. Like Caliban, the monster ultimately rebels and attempts to kill its master. Captain Adams confronts Dr. Morbius with the fact that he is giving form to his subconscious, and his guilty conscience, from having brought it into existence, finally ends the monster's destructive rampage.
In the 1965 movie Doctor Zhivago, during the scene where Victor Komarovsky convinces Zhivago to allow him to rescue Lara by taking her to Vladivostok, Komarovsky refers to himself as a Caliban: "Do you accept the protection of this ignoble Caliban on any terms that Caliban cares to make?"
Caliban was the central character in James Clouser's rock ballet Caliban, a 90-minute adaptation of The Tempest that was scored with live performances by St. Elmo's Fire (band). The rock ballet was performed in Houston, Dallas, and Chicago in 1976 and 1977.
In the Swedish 1989 film The Journey to Melonia, an animated film loosely inspired by The Tempest, there is a character named Caliban, a creature whose face consists of mainly vegetables. Unlike Caliban in The Tempest, this Caliban is kind at heart, and even becomes a hero later in the film.
Caliban is the central character in two works of fiction that act as both re-tellings of and sequels to The Tempest: Caliban's Hour by Tad Williams (HarperCollins, 1994, ISBN 978-0061054136) and Rough Magic by Caryl Cude Mullin (Second City Press, 2009, ISBN 978-1897187630). In both works, Caliban is a more noble character and presented more as Prospero's victim rather than the villain in Shakespeare's play.
Caliban is a supporting character in Grace Tiffany's novel Ariel (HarperCollins, 2005, ISBN 978-0060753276), another re-telling of The Tempest; rather than having a monstrous shape, he grows up to be a handsome teenager, with his only deformity being a twisted left leg, and it is Ariel's cruel illusions and deceptions that make Prospero see him as a monster.
Rob Thurman's Cal Leandros series (first published 2006) centres around Caliban "Cal" Leandros, a half-human, half-Auphe (a nightmarish monster) hybrid who kills monsters for fun and cash in NYC with his human brother and their sleazy cohort, car-salesman Robin Goodfellow. This Cal struggles for control every day against his monster half, dealing with sarcasm and dark humor.
The 2012 Summer Olympics opening ceremony (directed by Danny Boyle) titled Isles of Wonder (a name inspired by The Tempest) was heavily influenced by The Tempest. The musical piece played during the torch lighting ceremony was entitled "Caliban's Dream", and Caliban's monologue from Act 3, Scene ii was quoted by Kenneth Branagh in character as Isambard Kingdom Brunel at the start of the Industrial Revolution set piece. "And I Will Kiss", the title of another specially commissioned track from the ceremony, is also a quote from The Tempest (2:2:148-149). These two songs also appeared on the ceremony's official soundtrack. The 2012 Summer Olympics closing ceremony also featured a recitation of the same monologue, this time by Timothy Spall playing Winston Churchill.
In the preface of The Picture of Dorian Gray, Oscar Wilde muses: "The nineteenth century dislike of Realism is the rage of Caliban seeing his own face in a glass. The nineteenth century dislike of Romanticism is the rage of Caliban not seeing his own face in a glass."