Kaya Gimm was a mechanic who ran a droid repair shop out of her home in Jedha City. Her older sister, Killi Gimm, was a member of the the Disciples of the Whills. During the reign of the Galactic Empire, Jedha was occupied by Imperial forces in order to mine kyber crystals for use in the Death Star's superlaser. Citizens began to die in great numbers in the mines and during attacks from insurgent groups attempting to drive out the Empire. These deaths lead to a large number of orphans within Jedha City. Gimm was persuaded by her sister, Killi, to turn her home and droid repair shop into an orphanage.
Gimm became friends with Chirrut Îmwe and Baze Malbus, who shared in her sister's religion as Guardians of the Whills. Îmwe and Malbus helped the Gimm sisters maintain the orphanage by stealing supplies from the Empire. The Empire retaliated, destroying Gimm's home and forcing the sisters and their charges to flee. Malbus found an abandoned home for the two sisters to move into along with their orphans. A few months later, it soon became clear that Jedha was no longer safe for the orphans and Gimm sisters. With the help of Saw Gerrera and his Partisans, Îmwe and Malbus were able to steal a Sentinel-class landing craft in order to evacuate the Gimm sisters and the orphans. However, due to her poor health, Killi decided to remain on Jedha. Kaya and the orphans departed, hoping to find a safer world.
Kaya Gimm's description was similar to Gavra Ubrento.
Kaya Gimm appears in the 2017 canon young readers novel Guardians of the Whills by Greg Rucka. Her description in the book (blue coveralls, two long braids and dark make-up around the eyes) matches the look of another background character seen in Rogue One, Gavra Ubrento, who is mentioned in the young readers novel but does not appear in the story herself.