Elphaba is born in Munchkinland to a minister, Frex, and his wife, Melena. She grows up in the marshy Quadling Country in the south of Oz, where she sees the Wizard's people decimate the local population. At Shiz University, she becomes aware of the Wizard's oppression of sentient Animals and eventually drops out of school to move to the Emerald City and join a radical resistance network. She falls in love with Fiyero, a married prince from the western Vinkus region. When the Wizard's troops kill Fiyero because of his connection to Elphaba, she goes to his home in Kiamo Ko to seek his wife's forgiveness. There she studies sorcery and continues research on Animals and animals. Her temperament and her activities earn her the nickname the Wicked Witch of the West.
Glinda is born with the name Galinda but changes her name in college. When she arrives at Shiz University, she is a superficial sort, obsessed with clothing and social connections. She resists being assigned Elphaba as a roommate, but the two develop a friendship as Glinda slowly appreciates Elphaba's intelligence and discovers her own friends' shallowness. After their professor, Dr. Dillamond, is murdered, Glinda changes her name from Galinda to honor him and begins to study sorcery. After college she marries Sir Chuffrey in Gillikin. She is by now a powerful witch, marginally involved in politics; her friendship with Elphaba is severed when Glinda gives Nessarose's sparkling shoes to Dorothy after Nessarose dies.
Nessarose, or Nessie, is Elphaba's younger sister, born without arms, likely a result of a medicine their mother took to prevent Nessarose from being born green. She requires constant supervision and assistance from Nanny to keep her balance until Glinda enchants a pair of dazzling shoes, made by Nessarose's father, to help her stand on her own. Free for the first time in her life, and with Elphaba disappeared into the Vinkus, Nessarose assumes the birthright role of Eminent Thropp in Munchkinland and rules with a heavy hand guided by her oppressive and inflexible religious beliefs.
Boq is a humble farmer from Munchkinland who attends college with Elphaba and Glinda. He falls in love with Glinda, who rebuffs his attentions because he lacks both social and physical stature. Boq recognizes Elphaba from their childhood playgroup and becomes close friends with her and joins her as an assistant in Dr. Dillamond's research into the nature of Animals and animals. In later life, as a married farmer in Munchkinland, he tries to talk Elphaba out of her self-destructive spiral after Nessarose's death.
Fiyero is a member of Elphaba and Glinda's social group at Shiz University, and he later recognizes Elphaba when she lives as an anonymous radical in the Emerald City. Although Fiyero is married, he and Elphaba fall in love and have an affair. The Wizard's troops capture him after Elphaba tries to assassinate the Wizard. Fiyero disappears and is presumed dead, although his body is never found.
Sarima's parents arranged her marriage to Fiyero, so their marriage is based more on business than love. He leaves her and their three children for long stretches when he does business in the Emerald City. After his death, Elphaba travels far to visit Sarima and ask her forgiveness, but Sarima does not allow Elphaba to tell her story. Instead she befriends Elphaba, giving her rooms in the family fortress of Kiamo Ko. The Wizard's troops take Sarima and her family while Elphaba visits Nessarose in Munchkinland. Despite Elphaba's efforts to save them, Sarima, her sisters, and her children are presumed killed. Only her daughter, Nor, emerges later as the Wizard's prisoner.