Erebus is a large, rogue gas giant. It has remained in obscurity for quite a while until a strange signal was detected in 3248 from an object within its vicinity.
Features
Erebus is for the most part, a standard, run of the mill gas giant, with rapid winds racing throughout its eternally darkened skies, orbited by an entourage of moons.
Unlike most other gas giant though, I doesn't have any visible cyclonic storms or vortexes within its atmosphere. The only noticeable feature are its cloud bands.
Moons
Hypnos
This small, seemingly unassuming moon was the source of the mysterious signal received in 3248. While it seemed like a dark uninhabited wasteland from a distance, further inspection revealed strange lights on a region on the surface. A robotic drone that was sent to the surface discovered that these lights were cities, controlled by a strange mechanical society which is ruled by bio-mechanical brain-like entities. It is unknown who or what created these alien machines. It is kept warm by the gravitational pull of Erebus, having a temperature of 27 °C.
Pontus
Pontus is a hot oceanic moon, with a larger than average size. Hurricanes, monsoons and strong wins rage across this darkened water world. No life exists here nor have any of the Hypnosian machines colonised it. It has a temperature of 191 °C.
Other moons
A total of 71 moons orbit circle Erebus including, Hypnos, Pontus, 2 deserts and 6 ice worlds with the rest being asteroids.
Constructs
Later expeditions have revealed what appears to be a half completed, ring-like structure in orbit, that looks like it'll surround Erebus upon completion.
Within the planet itself, several mechical constructs have been detected, each rougly 35km across. They seem to have a pointy shape, no doubt to navigate the windy skies better. The purpose of these constructs is undetermined.