Gav was born in the 20th century, but got himself cryogenically frozen as he entered middle age and wasn't defrosted until just before the Teraport Wars. Since his estate and the webcomic he used to support himself with were gone and forgotten, he became a wormhole scientist and grew to be respected in the field. He always had trouble getting a pint of his favorite Guinness, since the Guinness brand was also gone and forgotten.
He was recruited by the UNS after the Battle of the Buuthandi to examine Target Echo, along with Kevyn Andreyasn and Triniko. When the three scientists figured out that the UNS intended to dispose of them afterward to protect the secrets they were looking for and refused to work further, their jailer, Captain Megiddo, decided to blast one of the three as an example to the other two. He selected Gav, but Gav foiled him by stepping through a duplicator wormgate that outputted to the gate-clone prisons.
All 950 million of them.
Megiddo blasted the original, but that didn't change the fact that in an instant Gav had gone from being a single, doomed individual to an entire galactic demographic. There are so many of him now that his tastes in entertainment, foodstuffs and the like have become major industries, and he outnumbers several entire sentient species.
Most of the Gavs have moved on to other pursuits, since the galaxy only needs so many identical physicists. Of course, what he moved on to can only be understood statistically.
Recently, the company Gavcorp has invented a differentiation process, allowing Gavs to physically and mentally remake themselves into unique individuals. The process is so effective that even Gav's old friends cannot recognize the differentiated ones. Almost all "baseline" Gavs introduced to the so-called "transmogrifier" have decided to use it, although the process had to be randomized to prevent them from all choosing the exact same mods and ending up identical again.