Pelarian biology is extremely similar to that of Humans. As aside from variations in cellular decay during the natural aging process Pelarian physiology and systems function the same as humans and there are no other obvious outwards physical differences.
As well, internally there are some minor differences in organ structure including: a slightly higher blood oxygen, and a tri-lobed brain structure, and a single kidney.
Pelarian culture was relatively peaceful with steady technological advancement and a progressive social structure. They were roughly equivalent to Human society on Earth around 2100s. However after their population is decimated by an alien threat, their remaining population is forced to abandon their homeworld and take refuge on a moon elsewhere in their solar system.
Having lost their home world, and all but a fraction of their civilization remaining, the Pelarian desperately venture out into the galaxy. The toll on their civilization was great, splintering the survivors into several factions and turning the once prosperous and peaceful race into scavengers, raiding human colonies throughout several systems.
2250 - Didymus is caught in the path of a freak meteor storm suffering multiple large surface impacts. Dust and debris launched into the upper atmosphere result in a number of ever worsening environmental declines.
2335 - With severe shifts in climate and frequent devastating earthquakes Pelarian society approaches a critical collapse. Some of the population begins to move off-world to a number of space stations and a temporary colony on the planets moon. Unfortunately dwindling resources and collapsing social structures makes those able to defect a very limited few.
2342 - Scientist researching the causes of the drastic environmental changes discover an alien technology buried deep below the planet surface. This alien hardware is using the planets core to power a massive machine that is devouring the planets raw resources from the inside out. It is believed that the meteors that had bombarded the planet years prior were actually the seeds for whatever this thing was.
2350 - Several attempts are made by the Pelarian militaries to stop the alien technology and the mysterious invaders respond. Hordes of mechanical creatures erupt enmass from the impact craters formed almost a century prior. The mechanized plague spreads across the planet devouring resources and decimating the Pelarian population.
2378 - Having lost their home world, and all but a fraction of their civilization remaining, the Pelarian desperately venture out into the galaxy, encounter another humanoid species with shockingly similar biologies. With few resources the Pelarian begin to scavenge, and eventually raid, the resources of these new aliens.
2387- After years of minor conflicts, with what is believed to be a small Pirate Clan group using alien tech, resulting in ship and resource loses. Brotherhood forces track a raiding party to discover that the culprits are in fact not the Clans, but a previously unknown alien race. After discovering the Pelarians and learning of their desperate plight, negotiations between the alien race and humans began. While some of the displaced Pelarians rejected the idea of trusting humans, the majority of them gave into offers of supplies and trade.
The Pelarians have strong political ties to the Lumus, although with very little to offer, the relationships is mostly that of accepting aid.
Their alliance with humans further split their already fractured culture resulting in a number of internal conflicts. The bulk of the Pelarian civilization supports the Human connections and work to rebuild their society. However several factions continue their history of raiding and scavenging. For the most part the behavior is tolerated by the Lumus and Brotherhood as it is a minor annoyance, allowing the Pelarians to work out their differences on their own.