Extremis

Posthuman species engineered for survival in extreme environments.

Biology

Their noses are narrow and flat, with slit-like nostrils that open and close in rhythm with breathing, to minimize exposure to cold or contaminated air. Lungs are capable of breathing at much lower pressures and oxygen concentrations. They regulate their temperatures with biological heat pumps using a coolant circulated through a blood vessel-like system ("heat vessels"), pumped by a compressor organ. This system can shed excess body heat by routing it to the limbs, or concentrate it in the core to ward off cold.
An extremis' movements are smooth and fluid when compared to a human's.
Their bodies are more rotund, with thicker sturdier bones. They lack hair, to form better seals with masks and keep cabin contamination down.
They have a variable circadian rhythm, capable of adapting to short days, long days, and no days at all on a tidally-locked world.

/* Like a chameleon, they can vary the darkness and color of their skin to adapt to local sunlight conditions.
*/

They also have better conscious control over their emotions, and are capable of mediating to enter a torpor-like state useful for passing time in monotonous situations.

/*

Psychology

The extremis were engineered to withstand indefinite-duration space travel, as their original purpose was to work aboard asteroid redirection ships and meteor-minders in the Outer System for terraforming efforts. Hence, they do not suffer from cabin fever and a consequence of this is tend to see mundane experiences as novel; they don't start ignoring things that happen often.*/

Civilization and Culture

History

The first Extremis lineages got their start during the Second Interstellar Period. In modern times they are known for, among other things, settling red dwarf systems which are plentiful and often barely used by other cultures.

/*Modern Extremis trace their roots back to the first human space colonists, who had to survive being cut off from Terra when civilization there collapsed. Many turned to genetic engineering, adapting their descendants for life in harsh environments. Over the following centuries and millennia, this has culminated in their current posthuman biology.*/

Interspecies Relations and Assumptions

On account of their inhuman appearance, behavior patterns, and preferred habitats, the Extremis are often regarded with apprehension or suspicion by human and posthuman cultures. Long-lasting rumors tell of Extremis space pirates lurking in the outer reaches of inhabited systems, waiting to snag unfortunate travelers and smelt them down for phosphorous.

Genetic Ancestor(s)

• Human

Scientific Name

Homo extremis