Alia Atreides is Jessica and the Duke Leto’s daughter and Paul’s sister, conceived just weeks before the Duke Leto’s death. When Jessica undergoes the Water of Life ritual, which will transform her into a Reverend Mother, Alia is affected by the transformation and receives the same visionary powers as Jessica. This causes her to gain consciousness in the womb, and when she is born, she possesses the intelligence, memories, and wisdom of her past ancestors and the previous Reverend Mothers. While Jessica fears this shock to Alia’s system might destroy the child’s mind, Alia grows into an empathetic and loving girl who has a strong relationship with her mother, Paul, and Harah. She also can communicate telepathically with her biological family as well as the Reverend Mother Gaius Helen Mohiam, as they all share similar powers. Alia is considered strange by the Fremen and is not entirely accepted by the tribe, but her preternatural powers and abilities only increase the Fremen’s sense that Paul and his family are special, divine figures.

Although still a child in physicality, Alia participates in the Fremen’s insurrection against the Harkonnens and the Emperor, and eventually kills the Baron with a poisoned needle. Baron Harkonnen’s quick and painless death at Alia’s hands symbolizes the absolute dominance of House Atreides. The Baron had previously been a formidable and terrifying enemy that was always strategically several steps ahead of his adversaries, but his anticlimactic death shows that Paul and House Atreides have reached an unchallenged level of supremacy. Additionally, Alia’s actions show the difference between the ethics of House Atreides and House Harkonnen – while the Baron would have enjoyed brutally torturing Paul and his followers, Alia uses a quick-acting poison that kills him almost instantly and painlessly.