The Xorthons have green skin and possess four eyes. WIP
The Xorthons maintain an intergalactic empire with many planets and moons under their control as well as enslaving any sentient races on those worlds.
The Xorthons possess very advanced technology such as FTL ships and have large disk shaped spacecraft called sweepers which fire lasers capable of destroying a planet's ecosystems from orbit. Another method they use is using genetically engineered bacteriums that can detect bio-signatures and infect other lifeforms.
The Xorthon empire is relatively small, only occupying 20 or more worlds. While they wish to expand, the Commonwealth has been keeping an eye in them and could easily defeat the Xorthons if they ever tried to start a war, so the Xorthons just kind of angrily exist with the Commonwealth.