Nebulee

The Nebulee were a group of scientists who pioneered the settling and terraforming of Venus, much like the Jovians did on Jupiter's moons. When the Jovian War broke out they hid beneath the clouds. By the time the war ended and the Emperor tried to reestablish contact with Venus he found the Nebulee much changed.

They had changed themsevles so they could survive on Venus unaided. Most of their thoughts happen on a different energy level and maintains a presence on the physical world by manipulating specially prepared gas molecules. Where one Nebulee ends and another remains a mystery to this day but they can, and do, organise themselves in roughly humanoid form to interact with regular humans.

They maintained peacful relations with the Empire until the uprising in 74 IY, only allowing resettlement of Venus in 210 IY.