The El-Aurians were a widely traveled people who spread themselves across many parts of the galaxy and beyond. At least one El-Aurian, Guinan, visited Earth in 1893 before Humans had any official knowledge of alien species. (TNG: "Time's Arrow", "Time's Arrow, Part II") Another region which the El-Aurians visited was near System J-25. (TNG: "Q Who")
Around 2265, when Guinan wasn't present, this species was the victim of a major attack by the Borg, with all but a handful of El-Aurians being assimilated or killed and all El-Aurian cities being destroyed. (TNG: "Q Who", "Ensign Ro", "I Borg") The El-Aurian fatalities numbered in the millions, which included Tolian Soran's wife and children, and the loss of their homeworld scattered the survivors throughout the universe. (TNG: "Q Who", "The Best of Both Worlds", Star Trek Generations) On the other hand, by resisting when the Borg came to assimilate them, the El-Aurians defied their attackers' motto that "resistance is futile." (TNG: "I Borg")
In 2293, a group of 415 El-Aurian refugees were traveling to Earth, following their escape from the Borg, transported on two ships, the SS Lakul and the SS Robert Fox, when they were caught in the Nexus energy ribbon near the Sol system. None of the El-Aurians wanted to leave the Nexus, despite it endangering and eventually destroying their transport ships. The USS Enterprise-B was able to rescue 47 of the refugees, including Guinan and Dr. Soran. The survivors were in a state of panicked confusion and had at least some minor injuries. In the Enterprise's sickbay, they were given medical assistance and assured that everything would be alright by Pavel Chekov and a group of journalists who served as a makeshift medical team (although the mission cost the life of James T. Kirk, or so it was thought). (Star Trek Generations)
By 2368, there were still very few El-Aurians left, due to the Borg, and those who were still alive remained scattered throughout the galaxy, with no collective home any more. (TNG: "I Borg") While Guinan became the bartender aboard the USS Enterprise-D in 2365, Soran, following the Enterprise-B rescue, dedicated the next seventy-eight years (until his apparent death in 2371) to finding a way to return to the Nexus. (Star Trek Generations; TNG: "The Child") Martus Mazur, another El-Aurian refugee, visited Deep Space 9 in 2370. (DS9: "Rivals")
Externally, the El-Aurians were physically identical to Humans, in structure and even the range of racial phenotypes. (TNG: "The Child"; Star Trek Generations, et al.) El-Aurians had rybo-viroxic-nucleic sequences in their genes (similar to other humanoids, including Humans and Bajorans). (TNG: "Rascals")
A significant physical difference between Humans and El-Aurians was in the aging process, as the extremely long El-Aurian lifespan covered many centuries. One particular El-Aurian male was known to be a father of an adult when he was around two hundred years old in the 19th century, and to be in virtually perfect health at the age of around seven hundred years old as of the 24th century. This longevity also afforded them the opportunity to have many children. (TNG: "Time's Arrow", "Rascals", "Evolution")
A Devidian temporal vortex suddenly being opened could potentially injure an El-Aurian more than it could a Human, knocking the El-Aurian unconscious and wounding them in such a way that the El-Aurian couldn't walk thereafter unless they received medical treatment. (TNG: "Time's Arrow, Part II") El-Aurians might also suffer from more common physical sensations, such as thirst and tennis elbow. (TNG: "Time's Arrow, Part II", "Suspicions")
El-Aurians prided themselves on being a race of listeners, and appeared to have a form of limited empathic ability. Some used this to help others, acting as advisers or confidants. A few turned their talent to more dubious pursuits, becoming con artists and tricksters, such as Martus Mazur, while Dr. Soran used his abilities to help bring his genocidal plan to re-enter the Nexus to fruition. (DS9: "Rivals"; Star Trek Generations) El-Aurians usually didn't experience difficulties with parents relating to their children, as El-Aurian children were usually good at listening to their parents. (TNG: "Evolution")
As Data once speculated in an alternate timeline (basing his hypothesis on appearances), El-Aurians possibly had a precognitive awareness which superseded the normal flow of time and space, allowing them to be extraordinarily sensitive to the space-time continuum itself. (TNG: "Yesterday's Enterprise") Guinan was able to perceive the change from the regular timeline to the aforementioned alternate one and back again, switches that occurred in 2366, due to a disruption in the history of the starship USS Enterprise-C; the changes were felt by both the Guinan of the alternate timeline and that of the regular timeline. (TNG: "Yesterday's Enterprise", "Redemption II") After Data postulated his theory about El-Aurians being able to intuitively detect such alterations, the Jean-Luc Picard of that timeline admitted there were many things about El-Aurians which they couldn't easily explain. However, the faith he had in Guinan's "special wisdom", as he called it, was instrumental in resetting the timeline. (TNG: "Yesterday's Enterprise")
- "The Child" (Season Two)
- "The Outrageous Okona"
- "The Measure Of A Man"
- "The Dauphin"
- "Q Who"
- "Evolution" (Season Three)
- "Booby Trap"
- "Deja Q"
- "Yesterday's Enterprise"
- "The Offspring"
- "Hollow Pursuits"
- "The Best of Both Worlds"
- "The Best of Both Worlds, Part II" (Season Four)
- "The Loss"
- "Galaxy's Child"
- "Night Terrors"
- "In Theory"
- "Redemption II" (Season Five)
- "Ensign Ro"
- "Imaginary Friend"
- "I Borg"
- "Time's Arrow"
- "Time's Arrow, Part II" (Season Six)
Descriptive text about Guinan in the internal reference work Star Trek: The Next Generation Writers'/Directors' Guide stated that several El-Aurians met Jean-Luc Picard while he was serving as a lieutenant on board the USS Stargazer and that they fascinated him at that point. The description also explained that the fact they were often described as a group of listeners was because something about the species "encourages others to be honest when they speak." (; Star Trek: The Next Generation 365, p. 012)
The first canonical evidence of this species were references to Guinan not being Human. Wesley Crusher mentions in TNG Season 2 opener "The Child" that the crew of the Enterprise-D are curious as to where she has come from (Crusher saying he has heard that a rumored answer to that mystery is Nova Kron), and in later second season installment "The Outrageous Okona", Guinan makes a joke in which she refers to herself as a humanoid. Her "people" were first referred to in "Q Who", later in the same season, which also introduced the Borg. The first time Guinan's people were referred to as a species of "listeners" was in TNG Season 3 opener "Evolution".
In the writer's first draft of the script for TNG: "Rascals" (which had the working title "Maker of Dreams"), Guinan's people were referred to as having encountered a shapeshifter who, in the story, called himself "Caliban", in reference to a character from Shakespeare's The Tempest. The script established that Guinan's people commonly referred to him as a "Maker of Dreams".
According to the reference book Star Trek: The Next Generation Companion (3rd ed., p. 319), the El-Aurians were named after an "angel of flame" from ancient Hebrew lore. Though many people think the name of the species was first established in Star Trek Generations, it actually originated in DS9: "Rivals". However, the name was likely taken from early drafts of Generations, which were definitely in circulation around the Star Trek office at Paramount by the time "Rivals" entered production. (Star Trek: Deep Space Nine Companion (p. 109)) The name wasn't included in the first draft script of "Rivals" (dated 14 September 1993), which instead referred to Martus Mazur as being from one of numerous races of Listeners (the script didn't specify how many there were, nor what any of them were called). At one point in the same first draft script, Odo commented, "You Listener-types are the worst," to which Mazur replied, "I beg to differ, constable. Listeners – my race included – are the finest diplomats, counselors, advisors –" but Odo interrupted, ending the sentence with "– and con-artists in the galaxy." The references to Martus as an El-Aurian were added into the script by the time the final draft was submitted (on 18 October 1993) , by which point the name had already been featured in the first draft screenplay of Generations (dated 1 October 1993). Although early reports regarding Soran claimed he was a Vulcan, Rick Berman confirmed he would be an El-Aurian (in Star Trek: The Official Fan Club Magazine issue 97, dated June/July 1994). 
With Guinan having set a precedent of virtually always wearing elaborate hats, the El-Aurians in Star Trek Generations had to be effectively styled. Upon introducing them in the film's script, the screenplay physically described them as "humanoid and dressed in distinctive clothing."  El-Aurian hairstyles in the film were designed by Key Hair Stylist Joy Zapata. (Star Trek Generations production notes) Meanwhile, Costume Designer Robert Blackman was assigned the task of designing individual costumes for thirty El-Aurians. This challenge was welcomed by Blackman, as working on Star Trek: The Next Generation had involved him encountering tight budgets and schedules that usually didn't allow for more than seven alien individuals to be shown per episode. (Star Trek: The Next Generation - The Continuing Mission, p. 231)
Whereas the first draft script of Star Trek Generations called for a series of "photos and biographical information" of the El-Aurian survivors from the Lakul to be shown on a screen aboard the Enterprise-D, El-Aurians other than Guinan and Tolian Soran are ultimately shown in only one scene of the film, to depict them panicking but being aided by Chekov and the journalists in the Enterprise-B's sickbay. The master version of this scene, used in the first edit of the film, spotlighted all of these individuals. This is also the only time when any El-Aurian other than Guinan, Tolian Soran, and Martus Mazur has appeared on camera.