Gyla Petro hailed from Kalgo 13 and was a Human female. Affiliated with the Senex-Juvex region's House Petro, this Imperial scientist tragically became the sole survivor of a research team decimated by plant life on Kashyyyk. Subsequently, she accompanied Han Solo on a voyage to Constancia.
Born into the distinguished House Petro, Gyla Petro later became a biologist associated with New Worlds. She joined a mission to Kashyyyk with other biologists and Imperial soldiers to gather Orga plant roots. The soldiers' actions of clearing a path through the forest by destroying plants provoked the flora, leading to a deadly attack on the Imperials. Han Solo and Chewbacca intervened, rescuing Gyla, who was the only one to survive. After her rescue, Gyla was transported to a Wookiee city on a Sureggi and participated in the Life Day festivities. However, Solo's subsequent capture by Imperials, which forced him to descend to the lowest level of Kashyyyk, raised suspicions about Petro's potential role as an Imperial spy.
Later, while traveling with Han Solo and Chewbacca aboard the Millennium Falcon, Gyla found herself caught up in unforeseen events. Han received a distress call from Luke Skywalker and discovered the droids R2-D2 and C-3PO amidst the wreckage of Luke's spacecraft. Annoyed by the diversion, Gyla voiced her discontent, stating she hadn't agreed to a rescue mission. C-3PO's explanation of Luke's purpose further irritated Gyla, who viewed Han merely as a smuggler, not an ally of the Rebel Alliance. Despite her desire to disembark, Gyla was compelled to remain aboard as Han evaded Imperial forces. As the Millennium Falcon escaped through Constancia's ring, Gyla persistently requested to be released. Han successfully evaded the Imperials and steered the ship into a concealed base within the ring. Upon landing, Han disembarked to investigate, leaving Gyla on board. After Luke, Gamine, and Sharlee deemed the area safe, Gyla emerged from the ship. Together, they formulated a plan to transport Gamine to the planet's surface. Han and Sharlee would commandeer a TIE fighter as a diversion, while Gyla, Luke, Gamine, Chewbacca, R2-D2, and C-3PO would pilot the Millennium Falcon towards the surface. The diversion proved successful, and upon the Falcon's arrival on the surface, the group was celebrated as heroes.
Information suggesting Petro's possible espionage activities for the Empire was later documented in her files on Fusai, specifically within the Rebel-controlled BRT supercomputer Mistress Mnemos. However, Mnemos remained unaware of the specific reasons behind the suspicions surrounding Petro's allegiance.