[quote=Xaxl]
The assumption that there an "intergalactic underworld" is possibly a bit of a stretch, considering how all our factions are likely to operate in a relatively insular manner.Also, even if there was, it'd just be a "galactic" or "intragalactic" underworld. "Intergalactic" implies it spans more than one galaxy.
[/quote]

Well then I meant galactic underworld, and in my opinion if you have empires and civilizations that can cross the galaxy then naturally you would have crime syndicates. Criminals do not follow norms like lawful citizens do so regardless of how isolated you are, there is always the possibility of criminals who will use galactic space travel to make profits