Dusque Mistflier grew up on the world of Talus. She was the youngest of five children, and the only female. Her father was employed at a small firm manufacturing starship components, while her mother remained at home raising Dusque and her four brothers. When Dusque was young, her father's employer began accepting contracts for the Galactic Empire. The simple line worker quickly grew disenfranchised with his work, notably when he discovered what his equipment was being used for. This resulted in numerous dinnertime arguments with his wife. Dusque would often sneak out of her room and eavesdrop on her parents during one of their many arguments. Before long, however, Dusque's father suffered a convenient heart attack at work and died soon after. Dusque's mother became completely despondent from his death and grew into a mere shell of the woman she once was.
As Dusque grew older, she witnessed her brothers taking up her father's old position at the starship manufacturers. Her family's close connection with the Galactic Empire left a sour taste in her mouth, but she realized that life on Talus offered very little in the way of an alternative. One brother even enlisted in the Imperial Academy. His military career was short lived, however, as he was killed during a training exercise shortly after joining. With the death of the brother, Dusque's mother's condition worsened.
Dusque eventually attended college and graduated with honors at the top of her class. She specialized in xenobiology and soon joined the Imperial Corps of Bioengineers. She left Talus forever and never looked back.
As part of the Imperial Corps of Bioengineers, Dusque traveled all across the galaxy, studying animal life from dozens of different planets. She developed her skills in the fields of hunting, trapping and exploration, and became one of the most accomplished scientists working for the Empire. Her superiors, however, never gave Dusque her due recognition. She was consistently held back from advancement and lost several viable promotions to her male colleagues.
Dusque had a colleague and friend, Tendau Nandon, who was killed by the Empire, inspiring her to join the Rebel Alliance. Following Tendau's death, Dusque joined forces with Finn Darktrin, an undercover Imperial spy within the Rebel Alliance, on a mission to find a holocron containing the identities of Rebel sympathizers in order for it not to fall into Imperial hands. After obtaining the holocron on Dantooine, Dusque was betrayed and almost killed by Finn, had Luke Skywalker not saved her soon after Finn made his escape. Dusque survived the incident and remained with the Rebel Alliance.
Dusque Mistflier had long, waist-length brown hair and large gray eyes. During her time with the Imperial Corps of Bioengineers, she typically kept her hair tied back and wore simple, lab equipment fatigues. After defecting from the Empire, she began to wear more utilitarian clothing, including padded vests, hide-woven gloves and goggles.