History
An eccentric physicist named Price, after ingesting hallucinagens became obsessed with Ragnarök, and what humanity would be like after the world ending in fire. So he created the Worldengine, which tricked Yggdrasill into believing Ragnarök had already occured, and began created a new race of humans.
Habitat
Atmosphere
Post-Ragnarök humans were created to live in an environment devoid of organic life destroyed by fire, so their atmosphere would be full of atomized carbon-based life, on which they would feed.
Population
A dozen or so