Elfour, more commonly known as R5-L4, was an R5-series astromech droid that often assisted Kyp Durron while he piloted his X-wing as a member of the Dozen-and-Two Avengers.
In 25 ABY, while the Dozen-and-Two were conducting an investigation above Helska IV, the Yuuzhan Vong ambushed them, killing all the pilots except Kyp and [Miko Reglia], who managed to flee to the planet's surface; during this attack, R5-L4 was obliterated by a grutchin.
The destruction of the droid deeply affected Durron, who had grown to consider him a genuine companion.