Alicia Witt played Alia Atreides in the 1984 Dune movie
Alia Atreides, also known as St. Alia of the Knife, was the younger sister of Paul Atreides, and daughter of Leto Atreides I and the Lady Jessica.
Early Years
Alia was still in the womb when Jessica took the Water of Life. Thus she was pre-born, and highly susceptible to Abomination from before birth.
After living with the Fremen for several years, she was present in the palace in Arrakeen when her brother and his forces successfully conquered the combined forces of the Emperor's Sardaukar and House Harkonnen. During the invasion she poisoned Baron Vladimir Harkonnen - her maternal grandfather - with a Gom Jabbar.
Rise to Power
Alia as Imperial Regent
Upon the death of Paul, and with his children Leto and Ghanima still too young to effectively rule, Alia went from being a Princess to being the Imperial Regent of the Atreides Empire. She was corrupted by power and established a cult of personality, using rich trappings and grandiose titles such as Mahdinate to build considerable political weight.
It was during this time that she fell fully into Abomination, and was secretly tormented by the living personalities of countless ancestors. Chief among these was the personality of Vladimir Harkonnen, who sought to use his granddaughter as a tool to reclaim power from beyond the grave.
Relationships
As Abomination, Alia takes comfort in the metaphorical arms of Baron Harkonnen
Alia had few close, genuine relationships, largely due to her mentally and emotionally imbalanced state. Her relationship with her mother was strained at best, and simmered with deep resentment. And her interaction with Fremen was tarnished at an early age by their fear of her abilities and knowledge.
Though she loved and admired Paul, her brother, she also partly resented his influence. And her love for the original Duncan Idaho ghola was ultimately destroyed by a casual affair with Javid, one of her priests who secretly served the Fremen insurgents who plotted against her.
Death
However, with the emergence of Paul's twin children, particularly his formidable son Leto, Alia's powerbase was in jeopardy. Her position was further weakened by the arrival of her mother from Caladan, after decades away serving the Bene Gesserit, who sought an end to Alia's influence.
Despite desperate attempts to crush her enemies, Alia ultimately had a moment of clarity. Having ordered the assassination of The Preacher, and realizing it was her beloved brother, she realized the scope of the Baron's influence, and in a moment of clarity threw herself from a high window to her death. ==References and notes==
Legacy
The impact of Alia's religious powerbase was long-lived. Many considered her a revered figure for several hundreds of years after her death. Ultimately though, her influence had vanished by the time of Leto II's death - some three and a half thousand years later.
Behind the Scenes
In the Children of Dune TV mini-series, Alia kills herself with a crysknife.