Timmser was a towering female Human with cropped, fair hair. She served as a pilot of a tri-fighter for the Khuiumin Survivors pirate organization, specifically within their Rock Squadron. Before joining them, she had been part of Riistar's Raiders, another group working with the Invids and based on Courkrus.
During Corran Horn's undercover operation as Jenos Idanian, when he infiltrated the Survivors searching for his wife Mirax, Timmser became one of his wingmates in Rock Squadron. An expert pilot, she demonstrated an aggressive flying style. Despite being known for her strong personality among her fellow pilots and raiders, Corran believed she possessed the capacity for improvement. They developed a friendship during his time on Courkrus. When Admiral Tavira pushed for Corran's promotion to leader of Bolt Squadron, Timmser took his place as the head of Rock Squadron.
As the mysterious "Ghost Jedi," Corran's other persona, began to make waves within the Aviary, Timmser and Caet Shrovl escaped the planet aboard two tri-fighters retrofitted with recovered hyperdrives.