From Star Trek: Theurgy Wiki
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. Around 2265, while 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 by the Borg, and all El-Aurian cities being destroyed by them. By resisting when the Borg came to assimilate them, the El-Aurians defied their attackers' motto that "resistance is futile." When Guinan's homeworld was destroyed by the Borg, the El-Aurian species was scattered throughout the universe but nevertheless prevailed. One of the areas the El-Aurians visited was near System J-25.
In 2293, a group of 415 El-Aurian refugees were coming to Earth, following their escape from the Borg, and two ships were transporting the refugees, the SS Lakul and the SS Robert Fox, when they were caught in and subsequently destroyed by the Nexus energy ribbon, near the Sol system. The USS Enterprise-B was able to rescue 47 of the 415 refugees, including Guinan and Dr. Tolian Soran (at the cost of one James T. Kirk's life, or so it was thought).
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. 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. Martus Mazur, another El-Aurian refugee, visited Deep Space 9 in 2370.
Externally, the El-Aurians were physically identical to Humans, in structure and even the range of racial phenotypes.
El-Aurians had rybo-viroxic-nucleic sequences in their genes (similar to other humanoids, including Humans and Bajorans).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. A Devidian temporal vortex suddenly being opened could potentially injure an El-Aurian more than a Human, however, knocking the El-Aurian unconscious and wounding him or her in such a way that the El-Aurian couldn't walk thereafter unless they received medical treatment.
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. 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.