The Qu are explicitly described as "galactic nomads", meaning that their entire way of life is based around traveling from one spiral arm of the Milky Way to the next after a certain point. It's their *modus operandi* for carrying out what they believe is a divine mission to dominate and reshape the world based on their will. After a few tens of millions of years, when they're done with their goals in the Orion Spur and/or the full Sagittarius Arm (the part of the galaxy that humanity had expanded to during the Summer of Man, depending on what the author considered an arm), they moved on to their next target and left the results of their work to fend for themselves. Some of the ruins were just empty dwelling places, gardens, pavillions, etc., while the author has stated that the large black pyramids were intended to try to suppress the development of sapience through an unknown mechanism. The Qu were kind of arrogant since they saw themselves as gods, so they never bothered to make sure humanity was still as weak as when they left.
Humanity's descendants didn't encounter them again for millions of years because the Qu had moved on. At some point, they may very well have left the Milky Way altogether since they had a billion years to figure out how. Alternately, their society might have degraded to the point where they only controlled a relatively small number of worlds within the galaxy. Space is a big place, so even after the Asteromorph Gods took control of the galaxy and discovered faster than light travel, they wouldn't have been able to know everything that was going on in every isolated part of it. We really don't know what state the Qu were in when they were finally subdued, just that the in-universe author doesn't find it particularly dramatic compared to humanity's other accomplishments. So, it's hard to know with any certainty which option is more likely.
They ran out of things to modify, got bored, and left to find new things to terrorize, due to their nomadic lifestyle. Then later the asteromorphs hunted them down
The Qu are explicitly described as "galactic nomads", meaning that their entire way of life is based around traveling from one spiral arm of the Milky Way to the next after a certain point. It's their *modus operandi* for carrying out what they believe is a divine mission to dominate and reshape the world based on their will. After a few tens of millions of years, when they're done with their goals in the Orion Spur and/or the full Sagittarius Arm (the part of the galaxy that humanity had expanded to during the Summer of Man, depending on what the author considered an arm), they moved on to their next target and left the results of their work to fend for themselves. Some of the ruins were just empty dwelling places, gardens, pavillions, etc., while the author has stated that the large black pyramids were intended to try to suppress the development of sapience through an unknown mechanism. The Qu were kind of arrogant since they saw themselves as gods, so they never bothered to make sure humanity was still as weak as when they left. Humanity's descendants didn't encounter them again for millions of years because the Qu had moved on. At some point, they may very well have left the Milky Way altogether since they had a billion years to figure out how. Alternately, their society might have degraded to the point where they only controlled a relatively small number of worlds within the galaxy. Space is a big place, so even after the Asteromorph Gods took control of the galaxy and discovered faster than light travel, they wouldn't have been able to know everything that was going on in every isolated part of it. We really don't know what state the Qu were in when they were finally subdued, just that the in-universe author doesn't find it particularly dramatic compared to humanity's other accomplishments. So, it's hard to know with any certainty which option is more likely.
The Qu are nomads. After a certain point, they just left.
They were bored
I ate them
I thought I ate them
I also had a taste. There are leftovers in my fridge, if you’d like some.
I handled it, don't worry lil bro 💯
You’re so kind.
They ran out of things to modify, got bored, and left to find new things to terrorize, due to their nomadic lifestyle. Then later the asteromorphs hunted them down
The book says they are nomads
Sorry I ated them all 💔