As the eldest of a large Zeltron family, Gemilan - known as Gemi - grew up surrounded by siblings. She enjoyed school, excelling in mathematics and the sciences, but while she would have liked to take her studying further she knew it would not be possible. Her family was unable to afford the cost of university study, so she would have to find a job.
At the age of 16, she joined a tradeship as a trainee engineer and back-up pilot. Her birth-father was a pilot and she seemed to have inherited his skills, enjoying the challenge of flying the Dropkick Murphy whenever she could. She was surprised to discover that, as well as its legal cargoes, the ship also carried a range of less savoury goods in smuggling compartments. During a visit to Coruscant, Gemi was stashed in one of the hidden holds with a blaster to guard an illicit cargo of spice while the rest of the crew were undergoing immigration procedures. Unfortunately, the otherwise-empty ship was stolen by a couple of hot-headed young idiots seeking to escape Imperial entanglement. By the time the McCauley twins discovered her, they were far away from Coruscant - and her crew.
Jack and Connor McCauley would happily have abandoned their unexpected stowaway, but her engineering skills came in handy when the Dropkick Murphy kept breaking down. By the time they reached their destination, Gemilan had acquired a new nickname, Gremlin, because the brothers blamed her for the ship's mechanical faults. Unknown to Gremlin, the McCauleys were due to meet with a contact from the Rebellion, who was seeking to recruit them to the Alliance cause. However, they were caught in an Imperial ambush: Connor was shot, Jack and Gremlin barely escaped. Jack, nursing his grief, told Gemi he hoped he would never see her again and the pair parted company, leaving Gremlin with the Dropkick Murphy and its secret cargo of spice.
Experiencing the Imperial attack, combined with the Empire's growing repression of non-humans, motivated Gremlin to join the Rebellion. She put the Murphy in storage, spice and all, and signed up. She was sent to one of the Rebels' piloting academies, based on a planet known as 'Rainworld' for its stormy weather, and began her new career as a would-be fighter pilot. Her training officer was one Lieutenant Roy 'Lock' Callahan; the pair had, at times, a combative relationship as Gremlin struggled to adapt to military discipline but she loved the speed and responsiveness of her X-wing snubfighter, though she still had a lot to learn.
Just how much was made clear when Gremlin and seven other cadets graduated early into Bantha Squadron, which had Lock as its new XO. Their first mission was a disaster: the CO was killed, as were most of the cadets, and Gremlin initially struggled with survivor's guilt. The group was quickly transferred into the newly-constituted Red Squadron, commanded by a Mandalorian mercenary, Meg "Flash" Avern, and Gremlin settled into the role of a snubfighter pilot. Life expectancy was short; comrades quickly became family. Gremlin flew to protect her squadmates and her own family, far away on Zeltros. She made mistakes, survived and learned from them; bacta took away the worst of the physical scars and the support of her colleagues helped with the mental ones.
Gremlin is extremely loyal to her squadmates and takes happiness seriously - theirs and hers. She is passionate about the Rebels' cause, though not blindly idealistic - she is well aware of what they are up against and knows their realistic chances of survival. Sometimes this leaves her feeling down, a state alien to her usual Zeltron cheerfulness, and she needs to be coaxed out of her sadness to regain her normal place at the centre of a crowd.
Her skillset expanded when members of the Rancors, an elite Commando unit, joined the Reds. The squadron was trained to undertake clandestine special operations and in addition to her engineering knowledge, Gremlin became the unit's demolitions specialist, a task she enjoyed. Or as she put it happily, "This means I can blow Imps up in space and on the ground!" Lock, who had been CO of the Reds for some time, was heard to wonder aloud if this was a good idea after all.
Just before the Battle of Endor, however, Red Squadron was disbanded. Most of the team went into Wedge's Red and Lando's Gold Squadrons but, much against her will, Gremlin was posted to Blade Squadron to help train B-wing cadets in dogfighting techniques. She took part in the attack on the Imperial Star Destroyer Devastator as a B-wing pilot, albeit still wearing her orange X-wing flightsuit - her way of showing her allegiance to her former squadmates. When she was found by the SAR team after ejecting from her damaged B-wing, they first thought she was an X-wing pilot so her name did not appear on the list of Blade Squadron survivors. After recovering from her injuries, she was assigned to Renegade Wing.