Randolph "Rusty" Byrne is a former CIA agent, currently working for AEGIS and serving in a long-term assignment as bodyguard and AEGIS liaison for Jason Quill and Byron Quill. He is a highly effective field agent and combatant, a crack shot and well-versed in a variety of martial arts. Personality-wise, he is no-nonsense, cynical and worldly, with a dry sense of humor.
He has functioned as "uncle" to Jason and his step-brother Amir Quill, taking on additional roles as teacher, coach, and mentor to the boys, as well as teaching them methods of self-defense. He has demonstrated loyalty to both of them, within a framing of "tough love."
Rusty has no known children. A teen girl, calling herself Jenny Byrne, claimed to be his daughter from "an unfortunate incident" years ago, and joined the Quill Family team for some months, before it was revealed she was a phony planted there by a Russian science institute to steal some Quill technology and kill Byron. Her fate is unknown, but the institute was destroyed by an "accidental," but well-contained, anti-matter breach.
Rusty is currently lost and presumed dead, along with Byron, from a dimensional rift that Dr. Achilles Chin created in Washington, DC, two years ago.