The Lost Aqualish Regiment, more commonly referred to as the Lost Aqualish, constituted a group of Aqualish who had secretly established a colony on Talus, where they maintained a secluded existence for centuries.
The ancestors of the Lost Aqualish were an Aqualish military unit that had been secretly deployed to Talus during the Aqualish–Corellian War. This conflict was a short-lived, relatively insignificant border dispute that occurred in the Trans-Nebular sector hundreds of years before the Galactic Civil War. These Aqualish soldiers discovered a cave within the Talus wilderness and decided to settle there permanently, recognizing its suitability as a base of operations for their raids. Following the war's conclusion, the Aqualish remained hidden, continuing their isolated existence for centuries. The Lost Aqualish, known for their extreme paranoia and often described as deranged by those aware of them, meticulously concealed their base, constantly fearing a renewed outbreak of war. Although occasional clashes occurred between the Lost Aqualish and the Human settlers of Talus, their existence remained largely unknown to the broader galaxy.
For centuries, the Lost Aqualish had severed all contact with the outside world. Their isolation meant they were unaware of significant events such as the fall of the Old Republic or the Galactic Civil War fought between the Rebel Alliance and the Galactic Empire.
Subsequent to the Battle of Yavin, a number of Lost Aqualish warriors chose to operate as mercenaries on Talus, posing a significant challenge to the established local mercenary groups. In 1 ABY, a mercenary operating in Nashal hired a spacer to assault the Lost Aqualish cave, with the objective of eliminating as many Aqualish as possible.
Around the same period, several Lost Aqualish scouts were recruited by the Followers of Baba to serve as both scouts and snipers.