Dors Venabili is a robot who initially is assigned by Chetter Hummin to protect Hari Seldon while Seldon attempts to develop his theory of psychohistory. Their paths intersect at Streeling University, where Dors teaches history. The two fall in love and marry, adopting Raych Seldon as their son. Seldon thinks of Venabili as a human, although given her speed, strength, and intelligence, he suspects that she is a robot. In Prelude to Foundation, he maintains that Dors' robotic or human nature is of no concern to him: he loves Dors for Dors, even after being confronted definitively with her robotic nature Forward the Foundation. Dors' intelligence and knowledge of history become quite important to the Theory of Psychohistory.
The reader first encounters Dors Venabili in Prelude to Foundation. In 12,020 GE Seldon gave a talk about his fledgling theory of psychohistory at the Decennial Convention, which caused Cleon I to express interest in him. At the urging of Chetter Hummin (a.k.a. R. Daneel Olivaw), Seldon first moves to Streeling University to continue his research without his interference. That is where he is introduced to Venabili, and she is assigned the job of guarding him. She sticks with him as he moves to Mycogen, and later to Dahl and to Wye. Hari Seldon, meanwhile, guesses that Dors must be one of the ancient robots of Mycogene legends by the end of their journey. Despite of this, it is at the this point where Seldon and Venabili decide to marry and adopt Raych Seldon as their son. While at Dahl, Venabili has an opportunity to show her incredible skills at fighting. After saving Hari Seldon's life during an assassination attempt on the first year of his First Ministership, she receives the nickname "Tiger Woman."
When Raych Seldon marries Manella, Dors immediately shows her dislike for her and does not change that opinion until her death.