Leela

Leela was a warrior of the savage Sevateem, a tribe of primitive Humans. After traveling with the Doctor, she decided to stay on the planet Gallifrey.

Meeting with the Doctor
Leela, the daughter of Sole and friend to Tomas, was one of the Sevateem (the name originated as a corruption of "survey team") descended from the Mordee expedition. As weapons, Leela favored a knife and janis thorns, which caused first paralysis and then death. (DW: The Face of Evil)

Leela profaned the Sevateem's god, Xoanon. Her father died undertaking the ritual test of the Horda on her behalf, and failed. Leela faced the punishment of exile when she encountered the Doctor who resembled the Sevateem's mythic figure, the Evil One. The Doctor had earlier visited Leela's world, repairing the Mordee expedition's computer, Xoanon, and forgetting to remove his own personality from its mind. The conflict between Xoanon and the Doctor's personality had driven Xoanon mad, causing him to split into two personalities, one favoring the Sevateem, the other their enemies the Tesh. The Doctor restored Xoanon's sanity. As he prepared to leave the planet, the Doctor found Leela in TARDIS and, to the Doctor's dismay, they set off together. (DW: The Face of Evil)

Travels
Although Leela was a primitive, she was also highly intelligent; grasping advanced concepts easily and translating them into terms she could cope with. Despite the Doctor's attempts at "civilizing" and educating her, however, Leela was strong-willed enough to keep her savage ways. She usually dressed in animal skins and went around armed with her knife and Janis thorns, with which she did not hesitate to use on people who threatened her, much to the Doctor's disapproval. Alongside the Doctor, Leela fought Taren Capel (DW: The Robots of Death) and, in Victorian London, Magnus Greel. (The Doctor had attempted to show Leela how her ancestors had lived.) (DW: The Talons of Weng-Chiang) On another adventure (coincidentally to a time period near Magnus Greel's home time period), Doctor and Leela picked up K-9 who had formerly belonged to Professor Marius. (DW: The Invisible Enemy)

Life on Gallifrey
Leela trusted the Doctor enough that, when the Doctor, appearing to have gone power-mad, returned to Gallifrey and applied successfully for the position of Lord President of the High Council of Time Lords, Leela still trusted him. Banished from the Capitol, Leela joined the Outsiders, a band of outcast Gallifreyans lead by Nesbin and helped to repel an invading force of Sontarans. Leela had in the mean time fallen in love with the Gallifreyan, Andred of the Chancellory Guard and decided to stay on Gallifrey accompanied by K-9. The Doctor had a second K-9 to take along with him. (DW: The Invasion of Time)

She would spend the next few decades of her life in the Capitol. She served as bodyguard and confidante to Lady President Romana, another former companion of the Doctor. Andred and Leela conceived a child together, the first one born on Gallifrey for millennia. (Pythia had long ago made the Gallifreyans a sterile race.) (NA: Lungbarrow) In years to come, Andred vanished. (BFG: Weapon of Choice) Leela would get drawn into Time Lord power plays and conspiracies. Leela discovered that one faction had had Andred murdered. (BFG: Imperiatrix) During a civil war, Leela was semi-permanently blinded. (BFG: Fractures)

By unknown means, with her sight at last restored, Leela survived the destruction of Gallifrey in the Last Great Time War, though she ended up prisoner of the Z'Nai, who caused her age naturally again, after maintaining her youth for many years through unknown means. (BFA: The Catalyst)

Other information

 * When a Rutan ship exploded above Fang Rock, pigmentation dispersal caused Leela's eyes to change from a dark color to blue. (DW: Horror of Fang Rock)
 * Leela wrote with her left hand and threw knives and did other actions with her right, suggesting some degree of ambidexterity (DW: The Invisible Enemy).

Key Life Events

 * Leela meets the Doctor and goes traveling with him. (DW: The Face of Evil)
 * Following an invasion by the Vardans and the Sontarans, Leela decides to stay on Gallifrey with a native lover, Andred. (DW: The Invasion of Time)
 * Leela assumes the position of Lady President Romana's bodyguard and advisor. (Mentioned NA: ''Lungbarrow')
 * Leela and Andred conceive a child together. (NA: Lungbarrow)
 * Andred dies. (BFG: Weapon of Choice)
 * Leela survives the destruction of Gallifrey in the Last Great Time War. (Revealed BFA: The Catalyst)

Behind the scenes
The character of Leela was first conceived by producer Philip Hinchcliffe and script editor Robert Holmes. They wanted a companion in the mould of Eliza Doolittle in George Bernard Shaw's play Pygmalion: a bright but unsophisticated primitive who would learn from the Doctor. Writer Chris Boucher had submitted a story proposal entitled "The Mentor Conspiracy" which featured a character named Leela which fit Hinchcliffe and Holmes's ideas.

Although The Mentor Conspiracy was not produced, Boucher reused the character of Leela for The Day God Went Mad (later renamed The Face of Evil), seeing her as a mixture of Emma Peel from The Avengers and Leila Khaled. Boucher was asked to write two endings to Face, one where Leela left with the Doctor and one where she stayed behind. The decision to have Leela become a companion was made soon after.

Initially, Leela was to have only appeared in three stories. It was later decided that she would stay for all of Season 15. One consequence of this decision was a plot contrivance being added to Horror of Fang Rock to allow the character's eye colour to change, so that actress Louise Jameson would no longer have to wear uncomfortable coloured contact lenses.