Alianna Slen, a female Human and a resident of Zakuul's Eternal Empire, was the offspring of Overwatch administrator Tayvor Slen. She became affiliated with the Flamechasers, a group devoted to the anarchist Firebrand. Alianna proudly bore extensive facial scars as a symbol of her commitment. In 3630 BBY, Firebrand, leveraging Alianna's access through her father, convinced her to retrieve Overwatch data and assist in planting explosives throughout Zakuul. Alianna had a final rendezvous with Firebrand to deliver the data and reveal that the remaining Flamechasers had abandoned the cause and were removing their scars.
Ultimately, Firebrand and the Commander launched an assault on the Overwatch, resulting in Tayvor's death and the destruction of the droid controls, which disabled numerous droids essential for Zakuulan civilization. Knowing that Firebrand intended to detonate the planted bombs, Alianna was relieved that a larger catastrophe had been prevented.
Alianna Slen is a character in Star Wars: The Old Republic: Knights of the Fallen Empire, specifically in Chapter X: Anarchy in Paradise. Should the player choose Dark Side actions and trigger the bombs, Alianna is wrongly identified as Firebrand by the Eternal Empire and faces execution.
A Zakuul News Bulletin mistakenly spells her last name as Slenn.