Star Person (All Tomorrows)

The Star People are a posthuman species that lived in a united solar system. They are the descendants of the Martians and the people of earth.

Biology
The Star People were genetically engineered humans with bigger brains and heightened talents, in every way superior to the humans of earth and the Martians.

Aftermath of the civil war
After the civil war between Earth and Mars, the humans of both planets agreed, that to overcome their differences, they had to become one species again. So they decided to create a new human subspecies which was able to adapt to the environment not only of Earth and Mars, but also of other, newly terraformed planets. They were also modified to have a bigger brain and heightened talents than their predecessors.

The people of both planets were given the choice between sterilization or giving birth to the new human subspecies. In the aftermath of the civil war, there were only small complaints to such a severe decision.

After only a few generations, the Star People united Earth and Mars and colonized Venus, the asteroids and the moons of Jupiter and Saturn. After that, they started to travel to planets beyond our solar system.

Colonialization
The first attempts to interstellar colonization were generation ships, but those succumbed to technical difficulties and anarchy after a few generations.

The next attempt was to send fast, semi-sentient ships to the stars. Those were programmed to terraform the planets they found and rebuild the Star people from genetic information stored on board.

But the first humans created by those machines viewed the machines as their parents and rejected other humans. Nearly half of the colonies founded by the machines perished because their humans only had eyes for the machines, not for each other. But the other half was enough to colonize one spiral arm of milky way with star people. Many colonized planets were devastated by humans and had their native ecosystems replaced by cities and small groups of earth-derived animals and plants, genetically modified to survive on those planets.

The Summer of Man
The surviving colonies prospered and some even surpassed the colonies of the solar system. Through ultra-fast communication methods, the star people of all those worlds stayed in contact, even though they never met each other.

Caused by this, technology rapidly grew and new inventions were shared with other colonies. Living standards rose to previously unimaginable levels.

Qu
On one of the worlds, the star people found fossils of a creature they called Panderavis and which turned out to be a highly derived dinosaur from earth. This was the only earth-descended creature on a planet of tripedal creatures with copper-based skeletons, and it served as an early warning that other civilizations were here before the star people.

Because nobody knew if the creators of this creature were still out there and if they were benevolent or not, humanity began stockpiling weapons again. These weapons were strong enough to nova entire stars and destroy solar systems.

But when they finally made first contact with another sapient species, called Qu, they were annihilated. Offended by that thought that another race than themselves tried to rebuild the universe, the Qu destroyed, depopulated or changed every human world within less than 1000 years. Many humans were genetically modified to mere animals who served as pets or slaves to the Qu or were left alone, unable to recreate their civilizations.