According to Wikipedia:
Turanga Leela, known simply as Leela, is a character from the animated television series Futurama. Leela is captain of the Planet Express Ship and has an on-again, off-again relationship with Philip J. Fry. The character, voiced by Katey Sagal, is named for the Turangalîla-Symphonie by Olivier Messiaen.
Leela was born to Turanga Morris and Munda, two mutants dwelling in the sewer deep under New New York City. When Leela was still an infant, her parents gave her up to the Cookieville Minimum Security Orphanarium with a note scribbled with mysterious symbols to make an impression that Leela was an alien, so that she would have a better life than a typical mutant. For the first three seasons of the series Leela does not give up hope of meeting another member of her race of one-eyed aliens. In the episode “A Bicyclops Built for Two“, Leela meets Alcazar, a cyclops who convinces her that he and she are the last two members of their extinct race, only to discover that he is a shapeshifting impostor. Leela’s parents’ plan of concealing her origins works well until an industrial accident caused by environmentally irresponsible Bender brings Leela and her friends into the New New York City’s sewer system where for the first time Leela meets her parents and discovers that she is not a cyclopean alien, but is actually a sewer mutant.
In the episode “The Problem with Popplers“, Leela’s family name, Turanga, was used for the first time. The episode “Less Than Hero” establishes that among Leela and her parents, their family name is placed before the given name.
Leela’s orphan upbringing and mysterious origins have helped fuel the development of her character over the course of the series.
Despite her strong-willed nature, she often feels self-conscious about her distinctive appearance, and at one point elects to have surgery to give her the appearance of having two normal-sized eyes, though she later has this reversed. Leela’s single eye hampers her depth perception and is sometimes exploited for comic effect, for instance, in the episode “The Problem with Popplers” it is suggested that she actually is crashing into billboards every time in the opening credits, though it typically does not interfere with her ability to pilot the Planet Express ship (beyond crashing into the odd billboard) or her mastery of martial arts. She is very athletic and in great physical condition, with most males (of any species) unable to match her in physical combat.
Originally a career placement officer for new defrostees at a cryogenics lab in the year 2999, Leela quit her job after meeting Philip J. Fry, a defrostee from 1999, and Bender, a high-tech job-deserting girder bending robot. Together they are employed as the crew for Planet Express, an intergalactic delivery business run by Dr. Hubert J. Farnsworth. Leela serves as captain of the Planet Express Ship, proving herself to be a skilled officer and often rescuing her less-talented coworkers from peril.
A committed environmentalist and lover of animals, Leela defies Brannigan’s orders in order to save Nibbler from a collapsing planet and adopts him as a pet; later in the series Nibbler reveals himself to be a member of an ancient race of wise, sophisticated beings known as the Nibblonians. Her environmentalist beliefs resurface again in Into the Wild Green Yonder. Despite her love of animals and nature, she embarks on an Ahab-like quest to kill a space whale in the episode “Möbius Dick“.
Philip J. Fry: Leela’s and Fry’s relationship is a major plot line that runs throughout the series. Fry constantly seeks her approval, though she turns him down for dates consistently due to his immaturity, yet she has been quoted as saying that she loves his boyish charm. Of course, there are various moments when she does fall for him even briefly, especially whenever he would risk his life for her. She sees him as a true friend and does not want anything more of him, but it constantly appears as if she is hiding (and denying herself) deeper feelings for him. At the end of the film Futurama: Into the Wild Green Yonder, Leela openly admits to loving Fry, and shows greater attraction to him from the episode “Rebirth” onward, though their relationship varies.
In “The Prisoner of Benda“, the two share a romantic interlude, though their personalities have been switched to different bodies. In the episode “Fry Am the Egg Man“, while being hit on by Angus McZongo, she says that she and Fry are strictly platonic. In “Overclockwise“, Leela expresses concerns over their “on-again-off-again” relationship, but by the end of that episode, Bender reveals Fry and Leela’s future to them, and while the viewer is not told its details, Leela and Fry are clearly pleased with them.
Zapp Brannigan: Leela has pity sex with the pompous, idiotic captain Zapp Brannigan in the episode where he is first introduced, “Love’s Labours Lost in Space“; according to Groening, the episode marked a turning point in the series, as it showed that the writers could degrade the main heroine without alienating viewers from the show. Throughout the series, Brannigan constantly tries to entice her into dates and romantic encounters, much to her disgust. Leela’s romantic mishaps continue throughout the series, even as her friend Fry begins to take a serious interest in her. However, from the film Into the Wild Green Yonder onward, she confesses her love for Fry and begins an openly romantic relationship with him.
Lars: In the film Bender’s Big Score Leela begins a romantic relationship with an attendant at the Head Museum named Lars. They become engaged, but Lars after learning that duplicates created via time travel are scientifically known to die, he breaks up with her at the altar, breaking her heart. He later sacrifices himself by throwing himself atop an explosive to save Leela’s life. It is later revealed that Lars was in fact Fry, who had returned to the 21st century, where he spent many years, lost his hair and suffered damage to his larynx (thus disguising his appearance), before returning to the future. He left Leela at the wedding because he realized that his body would be doomed.
Though the series described Turanga Leela as a one-eyed alien in its first episodes, Futurama creator Matt Groening and executive producer David X. Cohen had in mind that she would turn out to be the child of sewer-dwelling mutants before the series was pitched to executives. The mutants later revealed to be Leela’s parents appear as background characters in the season 2 episode “I Second That Emotion“, providing an early hint at her origin. Later in the series it is revealed that her parents had given her up to an orphanage (styled an ‘orphanarium’) in order to give her a chance at living a normal life on the surface, posing her as an alien due to her lack of distinguishing mutant features. According to Groening, the cyclopean but otherwise comely Leela subverts the science-fiction cliché of glamorously perfect female heroines.
Leela’s name plays on Turangalîla, the Sanskrit title of the landmark Turangalîla-Symphonie by French composer Olivier Messiaen.The Turangalîla-Symphonie (1948) features four cyclical themes; its title, broadly translated, means “love song”.
An early file Groening compiled on Leela lists some of her intended qualities: “strong-willed, opinionated, gentle (when not fighting), gives orders, unlucky in love, loves weapons, loves animals.” Katey Sagal describes her as a “tough, strong career girl who just can’t get it together in the rest of her life…she’s vulnerable and hard at the same time.”
Besides her over-sized eye, Leela’s other notable features include her loopy ponytail and relatively large (for a cartoon female) nose. The ponytail was included so that Leela, like the other main characters in Futurama and Groening’s cartoon The Simpsons, would be recognizable in silhouette. Groening decided to give Leela a large nose just for fun, but the animators initially resisted the idea, believing that it was unnatural. Animator Gregg Vanzo notes that the artists also had initial difficulties drawing facial expressions and moods for Leela because of her single eye. Leela’s usual clothing consists of a low-cut white tank top, leggings and boots. Groening intended Leela to be portrayed as attractive and sexy, but had to instruct the animators to de-emphasize exaggerated aspects of their original design that were too “racy”. However, Leela is still considered attractive and sexy, even beautiful by several such as Fry and Zapp Brannigan. What Leela calls “this thing I wear on my wrist” (referred to in another episode as a “Wrist Lojackimator“) is capable of minor plot conveniences as needed.
Katey Sagal provides the voice of Leela. Sagal immediately wanted the role when she was asked to audition for Groening. She is one of the few primarily live-action actors in the Futurama cast. In an interview, Sagal said: “This is acting, but a different type of acting. You’re not using your whole tool here — your body and physicality — but it’s challenging that way. The animation work is really unusual. I don’t have the same experience doing it as the people I work with.” Sagal notes that she found out years after accepting the part that someone else had previously been cast as Leela but the creators had decided to replace her. She also notes that she doesn’t change Leela’s voice much from her own natural voice but she does try to make it a little higher-pitched.