Alia was one of the preborn, a child brought to full consciousness inside the womb. Alia was awoken when her mother ingested the Water of Life in the Fremen ritual that would change her into a Reverend Mother. Because of the fact that this left Alia with no strong sense of personal identity, the Bene Gesserit believed she was to be an Abomination, one possessed by the voices in Other Memory. Late in her reign as Regent of the Known Universe, she did indeed become possessed by the spirit of her maternal grandfather, Vladimir Harkonnen, which led to her being an effective enemy of both the Bene Gesserit and the remaining Free Fremen.
Alia was born in the deserts of Dune 8 months after the death of Duke Leto in the attack on House Atreides' stronghold at Arrakeen by House Harkonnen. Jessica after being invited to partake in the Water of Life ritual to take the place of the Fremen's aging Reverend Mother Ramallo as religious leader of the Fremen, drank of the potent poison and in the process of converting the Water of Life into a harmless substance became a Reverend Mother. The problem was that, unbeknownst to the Reverend Mother Ramallo, Jessica was pregnant with the Duke's daughter. When Jessica became a Reverend Mother, her daughter was affected as well, creating the first of the Atreides preborn.
Alia was raised as a Fremen in Sietch Tabr, and as such was deeply knowledgeable in the ways of the desert. Alia was always slightly odd, hinting at her preborn nature, and Fremen culture found the child to be disturbing, as most Fremen children were removed from adult society, whereas young Alia was always to be found with her mother in important meetings between leaders of the Fremen revolt against House Harkonnen. During the Battle of Arrakeen at the end of the Fremen revolt on Dune, Alia was captured and, during a meeting of the most important people in the universe at the time, including Shaddam IV Corrino and Vladimir Harkonnen, killed her grandfather with the gom jabbar, a needle tipped with instantly lethal poison used by the Bene Gesserit.
After the takeover of the Empire by Paul Atreides and the relocation of the Imperial Capital to Arrakis, Aria led a stressful life in the Imperial Palace. The weight of Other Memory was constantly upon her during day to day affairs. She was an important advisor to her brother and was spying on the affairs in the throne room when the Ghola Hayt was offered to Muad'Dib as a gift.
As planned by the group involving the Guild Navigator Edric, Reverend Mother Gaius Helen Mohiam, Tleilaxu Face Dancer Scytale, and Irulan Corrino, Hayt acted as both an intelluctual distraction to Muad'Dib and a seductive distraction to Alia. When Hayt's brainwashing is activated and nearly makes him kill Paul Atreides, the true Duncan Idaho's memories return to the ghola, effectively bringing Duncan back from the dead. Duncan and Alia fall in love, and when Paul walks into the desert as Fremen custom demands, the two marry.
After the apparent death of the Padishah Emperor, Alia is named regent for Paul's son, Leto II. Alia was wracked by even worse intrusions by Other Memory as she sought to gain the prophetical power Muad'Dib had held by ingesting increasing amounts of melange. During one such overdose, Alia's mind was bombarded by voices so overwhelming she was forced to accept the help of her grandfather, Vladimir Harkonnen. The acceptance of Alia allowed the dead Baron the chance he needed to possess Alia, creating an Abomination. The Baron's influence turned Alia into a more wrathful woman, and his own sexual perversions were brought upon Alia in the form of affairs with upper level aids.
Duncan Idaho, using his Mentat computing ability discovers Alia's condition and assists Jessica Atreides escape Alia's murderous plot formed after the attack on the royal twins and 'death' of young Leto. When Alia discovers Duncan's actions, she attempts to have him killed, though he narrowly evades her gaurds by stealing a 'thopter and claiming asylum in Sietch Tabr with Stilgar.
The possession by Baron Harkonnen was forcing Alia into a more ruthless governing style, and with the appearance of The Preacher, secretly her own brother Paul, Alia was incensed. The Preacher spoke of many subjects that were tainting the Empire, most notably the fact that Alia was an Abomination. At the final appearance of The Preacher, he gives such a speech as to cause one of Alia's preists to kill him on the spot. Leto II then reveals himself and unlocks Ghanima's hidden memories and proceeds to the throne room to confront Alia.
Alia is cornered in the Throne Room by Leto II, Ghanima, and Jessica, where she is forced out of her possession by the Baron Harkonnen by Leto. Alia fights the Baron's control, spitting words in many languages and many voices before finally the Baron's own voice issues from her mouth. He insults the Atreides before Jessica finally manages to help Alia throw off the Baron's control. Instead of face the Fremen Trial of Possession, Alia threw herself from the Throne Room window where she fell to her death.
Alia was one of the ghola children grown in Hunters of Dune.