Biggs Darklighter is a human male ace pilot who fought for the Alliance in the early days of the Galactic Civil War. He grew up on Tatooine as a boyhood friend of Luke Skywalker, left for the Imperial Academy, and defected after graduating in order to join the Rebellion. Garrick Hagon played him in A New Hope (1977).
At the Yavin briefing he meets Jek Porkins, and when Red Leader questions whether a farm boy can handle an X-wing, it is Biggs who vouches for Luke as the best bush pilot in the Outer Rim. He flies as Red Three and dies in the trench, shot down by Darth Vader while covering the man he recommended.
He is also the franchise’s most famous piece of missing footage. The Tatooine scenes establishing the friendship were cut from the 1977 release, which left the death of a stranger where the death of a childhood friend was supposed to be. Some of that material returned in the 1997 Special Edition — and the novelisation and the Marvel comics had been filling the gap for two decades already, which is why a generation of readers knew who Biggs was before they could see it.
The surname then spread. The Legends X-Wing novels gave the family a second Rogue in Gavin Darklighter, and Darklighter became one of the small threads binding the Bantam-era books back to the first film.