Hadesians

The Hadesians were a sentient race that inhabited the Hades System until about 300,000 years ago; It's theorized that they died out in an interplanetary civil war and eventual nuclear holocaust long before the advancement of any other known sentient race.

At an undetermined point before their discovery in 2515, they achieved spaceflight and settled on Hades I, Hades II, Hades III, and Hades IV. Contempt of their advancements, the race was incapable of expanding into other Planetary systems and hadn't discovered jump points. Hadesians were roundish creatures with a bulky central body and a maximum height of 2.1 m (7 ft) and 2.4 m (8 ft). Accompanying their large stature, the creatures' intimidating appearance was fortified by various thin appendages and lengthy, muscular arms.