Thaya Ferr was a female human operative within the Nihil, functioning as an aide to Marchion Ro, the pirate syndicate's leader known as the Eye of the Nihil. As Ro orchestrated diversionary strikes against Aleen, Japeal, Yeksom, and Tais Brabbo with the intention of drawing the Jedi away from the Starlight Beacon space station, Ferr kept him informed regarding the advancement of his plot to destroy Starlight Beacon. Although she lacked the almost fanatical devotion that most Nihil felt for the Eye, she unfailingly followed his directives. Determining that she lacked the aptitude for leadership, she chose to excel as Ro's most effective subordinate, a quality that did not go unnoticed by the Eye.
Aboard the Gaze Electric, Ferr's duties included disseminating transfer orders to various members of the Nihil. Upon returning to the bridge, she engaged in a conversation with Ro concerning the Jedi's attempts to apprehend Lourna Dee. Following the delivery of more transfer orders, she and Ro deliberated over the strategic implications of these movements. She had reassigned Roborhyan to the Spectre, a vessel captained by someone harboring a deep-seated resentment towards him. Furthermore, she instructed the Janikki clan to synchronize their efforts within the Ishbix system, where they were wanted for numerous offenses. She then elucidated to Ro how these actions would contribute to undermining potential rivals within the Nihil organization. After Ro gave the order to sabotage Starlight Beacon, Ferr gave deep thought to her position within the Nihil. She came to the conclusion that she had no desire to lead, wanting only to follow and help Ro as a second-in-command. She then made arrangements for a shipment of enforcer droids to be delivered to the Gaze Electric as a way to replace the living crewmembers who had been transferred off the ship.
Ferr proceeded with the activation of the droids designated to crew the ship, however, she was caught off guard when a small vessel requested permission to dock. Ro revealed to her that it was Ghirra Starros arriving to align herself with him. Ferr then understood that Ro had successfully manipulated her into betraying the Republic, which she found to be impressive. She facilitated Starros's relocation into Alfkenda's former living quarters. Following the act of sabotage against Starlight Beacon, Ro directed Ferr to monitor a specific communication channel for updates on the situation. She communicated the distress signal originating from Starlight Beacon after the top section of the station separated and was destroyed. As the events unfolding above Eiram were being broadcast across the holonet, Ro instructed Ferr to disseminate the information to the rest of the Nihil, proclaiming his responsibility for the destruction. He also told her to tell them not to come to Eiram and disrupt his plans. Ferr observed as Starlight Beacon plummeted onto Eiram, remarking on the symbolic significance of the Republic's ambitious project meeting its end on an unremarkable planet. Ro concurred, instructing her to display the planet's holonews feed so they could witness the station's final destruction.
After the crash, Ferr organized a celebration in a system far from the Republic's influence so the Nihil could enjoy the victory. Later, she hacked into communication buoys and allowed Ro to broadcast his ultimatum on the same frequencies once used by Starlight Beacon.
The debut of Thaya Ferr occurred in the 2022 novel titled The High Republic: The Fallen Star, authored by Claudia Gray as a component of the Star Wars: The High Republic multimedia project's Phase I. The character's visual representation was subsequently introduced in the eighth issue of the 2023 comic series Star Wars: The High Republic Adventures. The issue was written by Daniel José Older, illustrated by Harvey Tolibao, and published by Dark Horse Comics as part of the multimedia project's Phase III on August 7, 2024.