Gelrebbo was once an established businessman on his home planet of Malastare, fixing droids for fellow Dugs, especially podracing pit-droids. However, by sheer accident, one of his repaired droids not only botched but sabotaged a prominent racer's attempt at a prestigious competition, killing him in action.

Disgraced (and divorced), he lost great many customers. It was only through the help of his second wife, Margilla, years later that he overcame his depression and continued on. But, in the interim, he held depression off with a spice addiction, and it was too much.

Margilla left him after only a couple years, in which Gelrebbo went from planet to planet in search of himself. He picked up a few skills, primarily explosives, as a way to keep himself feeling alive with the excitement of nearly dying from blasts.

But, as he experienced the oppression of the Empire more and more on each planet he lived in, he became sympathetic to the Rebel cause, and was successfully recruited into the Alliance.

With refined training, he became the Rebel Alliance's foremost explosives specialist, with notoriety from his most recent work during the Liberation of Sullust. The volcanic explosions were minor compared to what he did to the Empire's refineries.

A rare combination of a depressed-soaked death wish, and a rebel cause to free the galaxy.