The arthenn were a species with highly advanced technology, though they confined themselves primarily to the Zelene system. They originated on the planet Helyme. An unknown cataclysm wiped out all complex life on that planet. Another of their colonized planets -- Epho -- shows indications that it was hit with an orbital bombardment.
The arthenn were wiped out by 298,000 CE.
Source[]
The arthenn are derived from Mass Effect.