A mercenary from the Lasat species was employed by Saw Gerrera and his Partisans during their campaigns which took place on the planet of Onderon around 18 BBY. To confront the rebels, a squad of Imperials, including Alexsandr Kallus, was dispatched to Onderon. This mercenary killed nearly all members of the unit, but chose not to kill Kallus. Later, Kallus, who was an agent working for the Imperial Security Bureau, told the story of his encounter with this mercenary to Garazeb Orrelios, another Lasat rebel.
In the novel Rebel Rising, which was released in 2017, a Lasat is present at Saw Gerrera's outpost on Wrea. Beth Revis, the author, was asked if the Lasat at Saw's base was the same one that Kallus had encountered, and she responded that she had intended for them to be the same character. Star Wars: Dawn of Rebellion: The Visual Guide placed the Lasat's actions on Onderon in 7 BBY, while Star Wars: Timelines placed the event around 18 BBY. Timelines also places Kallus's appearance in "Flight of the Falcon, Part 1: Spy Games," where Kallus is shown performing an Imperial mission, around 10 BBY. Because Ultimate Star Wars, New Edition and Star Wars Encyclopedia: The Comprehensive Guide to the Star Wars Galaxy state that his deployment to Onderon was Kallus's initial Imperial mission, the Lasat's attack cannot have occurred in 7 BBY, given Kallus's mission in "Spy Games."