The Nightsiders are a race of dark-furred, nocturnal bipeds, averaging about 1.4 meters in height. They were native to the planet Krrendar IV.
Nightsiders are asexual and reproduce by parthenogenesis. They release huge quantities of "seeds" into the oceans of the worlds they've settled, seeds which hatch into non-sapient tadpole-like aquatics that roam the oceans. Nightsiders only take interest in their "children" once they've emerged from the waters and metamorphosed into sapient adults.
The Nightsiders once hailed from the Krrendar system in the Triangulum Galaxy. But once they developed primitive industry, the Nightsiders ran roughshod over their homeworld, until by the time of Commonwealth first contact, Krrendar IV was nearly uninhabitable. Since their homeworld was evacuated, the Nightsiders can be found on a variety of mostly impoverished planets and outposts.
Because of their reproductive method, Nightsiders have no real connection to their parents. They have no permanent mates. As hatchlings, they literally eat their own siblings to survive. As a result, their society is ruthlessly competitive, with little or no check on even the most despicable behavior.
Now that their world has been ceded to the Pyrians (who found most of their "Pyroforming" work had already been done for them), Nightsiders have dispersed themselves throughout known space. While some have prospered in their new environments, many Nightsiders remain at the margins of Commonwealth society, a problem our best social scientists are working to alleviate.