Metathralsians 

By far the most perplexing humanoid species ever known, Metathralsians boast extremely high physical and magical capabilities, and an extremely low tolerance for other individuals. They dwell in remote burrows on asteroids and are infamous for their territorially provoked attacks on mining operations and deep space commuters. Known Metathralsian burrows are to be avoided at all costs and their locations clearly well marked. Negotiation and conversation with a Metathralsian is possible, but should not be attempted due to the inherent risk in interacting with a being so volatile and unpredictable.

Metathralsians were the result of vigorous genetic engineering programs based on the planet Sutheria I. Preserved records state that they were created when "jury-rigged" marrite magic was introduced into the genome of certain individuals, though the exact genetic traits necessary for Metathralsian development were not described. Shortly after their creation, the first Metathralsians escaped containment and caused significant devastation to Sutheria I's infrastructure. Since then, their numbers have been steadily increasing as they spread across interstellar space. 

It is currently unknown how they sustain themselves or reproduce.