Oumni

The Oumnis are a race of technologically-advanced humanoids living in the artificial illuminated caves of the planet Mercury, where they're protected from the planet's harsh weather.

Biology
Oumnis are humanoid in shape, and described as about the height of a tall man. Their facial features are described as beautiful by Humans. Some notable morphological traits include sinuous six-fingered hands, spurs on their heels, translucent white skin, and a mass of iridescent colorful filaments on their heads which resembles hair to some degree, but move around continuously, like worms.

Culture and society
Oumnis are a highly advanced civilization which sees itself as vastly superior and more evolved than other forms of life, such as Humans and Dlukus. Their knowledge of physical sciences is immense, and their technology notably includes a special kind of metallic sheath covering the ceilings of their caves which blocks out all kinds of damaging radiation, giving them what essentially amounts to biological immortality and immunity to all known diseases. They wear no clothes, other than protective suits when they venture outside their caves.

Appearances

 * "The Immortals of Mercury", by Clark Ashton Smith (1932)