Elphaba is the name given to the Wicked Witch of the West in Wicked: The Life and Times of the Wicked Witch of the West by Gregory Maguire, as well as in the Broadway adaptation, Wicked. In the original L. Frank Baum book, The Wonderful Wizard of Oz, the witch is unnamed and we know little about her life. Elphaba is modeled after the witch as she is shown in the 1939 classic movie The Wizard of Oz: Green-skinned, clad entirely in black, and wearing a tall peaked hat. Maguire formulated the name out of L. Frank Baum's name. L. Frank Baum became El-pha-ba. In both adaptations, Elphaba is also called by several nicknames including Elphie, Fabala, and Fae.

Elphaba is the daughter of Melena Thropp and the Wizard of Oz (a fact which Elphaba discovers near the end of her life). Her father's origins beyond Oz is one possible explanation of her green skin, and is the reason she is able read to the Grimmerie. Through her mother, she can lay claim to the title of Eminent Thropp of Munchkinland. Frexspar the unionist minister and missionary is her mother’s husband. Nessarose, the Wicked Witch of the East, and Shell are her half siblings. She has a son, Liir, who was illegitimately conceived with Fiyero, and unknowingly carried to term by Elphaba in a coma.

Elphaba is portrayed as an aspiring revolutionary, perhaps inspired by her childhood days in Quadling Country, whose ecosystem and people were stricken by the government’s ruthless ruby mining and road building efforts in the area. She is shown as a passionate supporter of Animal rights: (Animals, as opposed to animals, are speaking/thinking Animals.) she speaks against Madame Morrible’s anti-Animal poetry, works with the Goat Doctor Dillamond in attempting to find the biological difference between Animals, animals, and humans, protects a Lion cub in a life sciences class, and is often shown refusing to eat meat that could possibly come from Animal sources. Her revolutionary goals, however, fade after a failed assassination attempt on Madame Morrible’s life, which leads to the death of Fiyero, her lover.

The theme of forgiveness plays a large role in her life after this point, as she attempts to seek forgiveness for the death of Fiyero from his wife, Sarima. Sarima, however, refuses to listen to Elphaba’s story of his death, and she is murdered by the Wizard’s forces, leaving Elphaba unsatisfied, and plunged into madness. The theme comes full circle, and is instrumental in her death: Dorothy had come to the Kiamo Ko asking her forgiveness for killing Nessarose. Elphaba dies before being able to grant forgiveness of her own.

Elphaba is green, and several theories are put forward in the book to explain the phenomenon. Melena sees the color as a punishment for her infidelity to her husband, Frexspar sees it as originally as a result of his careless words “The devil is coming” on her birth day, and later as punishment for his failure to protect his parishioners from the Clock of the Time Dragon. The Wizard’s use of the Magical Elixir during Elphaba’s conception, along with the fact that the Wizard is of another world are also possibilities.

Elphaba is also seemingly allergic to water. This connects to the Elphaba’s ponderings over the existence of her soul: without water, there is no baptism. The final bucket splash is described as a baptism, after which Elphaba is clearly shown to have a soul.

This bucket splash also connects to the fable of Saint Aelphaba, for whom Elphaba is named, who was said to disappear beyond a waterfall, and never return. This in turn connects Elphaba with the stories that Sarima tells her children about a wicked witch who disappears into a cave. At the end of the story it's tradition that the children ask if the witch ever comes out, to which Sarima replies "not yet". At the end of the book, that dialogue is repeated, suggesting that Elphaba will eventually rise again. In interviews, Maguire has stated that the witch may die but will always come back, no matter what.