The solar system initially formed naturally like most galaxies, except that it was closer to the edge of the Milky Way, and inevitably became a binary system after many trips through the spiral arms. Binary or multiple star systems are actually very unstable in their main sequence star phase, which is not conducive to the formation and development of life, and it wasn't until one of the suns became a dwarf, and the gravitational pull of the magnetic field tended to be milder, that planets within the solar system actually began to have the biological conditions for survival and evolution.
By about 550 million years ago, the fifth planet of the solar system (the one between Mars and Jupiter) had been settled by human immigrants, when both suns were still in place, so Planet Five was the most habitable, when Earth was uninhabited because it was too hot.
It wasn't long before the reptilian intelligent beings that originated in the Celestial Dragon constellation (which cannot be called intelligent beings because they were created artificially, the same as humans at the current stage) came to the solar system during its expansion process, and after destroying the Fifth Planet without any effort, brought the entire solar system into the Celestial Dragon Empire's sphere of influence.
As cold-blooded animals, the Celestial Dragons like hot and highly radioactive environments, so the Earth, which the human race could not look at, became a habitable planet in their eyes instead, but at that time, the Earth was still in the barbaric period, and the survival conditions were not ideal, so the Celestial Dragons transferred a large amount of water ice formed after the shattering of Planet Five to the Earth, which made the Earth's environment greatly improved, and a part of the organisms on Planet Five was also brought to the Earth.
The Celestial Dragons soon left, leaving only a handful of the lowest-ranking ‘Green Dragons’ as administrators to watch over the Earth and the solar system, and then they introduced some creatures to the Earth one after another, mainly insects and reptiles, as these were the main food of the Celestial Dragons, and the Earth became a ‘ranch’ for the empire.
In the hundreds of millions of years that followed, although the creatures on Earth experienced several cycles of extinction due to some irresistible natural factors, such as the solar system travelling through the spiral arms, cosmic ray bursts, etc., this didn't prevent the Green Dragons from actually controlling the Earth as well as the entire solar system, and since their masters seldom interfered with the affairs of the remote solar system, the Green Dragons had in fact been the earthly emperors of the solar system, as long as they regularly paid the Earth Ranch produced materials to the Heavenly Dragon Empire on a regular basis, then they could always live comfortably in the solar system.
So theoretically, the Green Dragons were the first higher civilisation to land on Earth, but it was undoubtedly the Human Race that first discovered and landed in the Solar System, which would lead to even more controversy and conflict surrounding the Earth's affiliation in the long years to come.
Some of the lucky low-ranking Green Dragons stayed on Earth, and have been herding dragons since then, living a free and comfortable life, but the good times will come to an end, with the decline of the Tianlong Empire, the stable and affluent life supported by strong force will also be gone.
Time came to 65 million years ago, when was driven out of the solar system of the human race relying on today's technology is not the same as in the past and killed back, in fact, according to the rules of the human race, they will never invade any planet that already has a civilisation exists, but it is not coincidental that the human race has always believed that the solar system since ancient times is its inherent territory (this sounds a little familiar), you do not care whether I was settled on Earth, as long as it is me! discovered it first and surveyed the planet on the ground then I own it.
The human race sent ambassadors to Earth to negotiate with the Green Dragons, who, of course, thought that the human race's reasons were nonsense, when the Earth was too hot for them to bear, and they could only hide in underground caves during the daytime, and it was only after a number of environmental modifications and natural changes that the present vibrant Earth came into being, and you want to snatch all the fruits of our labours without doing anything, and it is impossible to agree to this kind of thing.
Both sides argued, no one could convince anyone, the patience of the Human Race was nowhere near that of the Reptile Race, so the Human Race came up with a trick, don't you guys like hot places? Well then, I'll get rid of one of the suns and see what you cold-blooded creatures do.
Sure enough after there was only one sun left in the sky, the temperature of the Earth began to plummet, which made it difficult for the Green Dragons and the dinosaurs to adapt, the Green Dragons were forced to ask for help from the Imperial HQ, but the reinforcements still couldn't beat the human fleet when they arrived, so the Empire decided to destroy the Earth, and what you can't get you destroy, which is the usual style of the Celestial Dragons.
Originally, the Green Dragons should have retreated with the army, but on the one hand, they did not want to leave their home, where they had lived for generations, and on the other hand, they were not too willing to return to the Empire as hard labourers, so they proposed to the headquarters that as long as they destroyed the ecological environment of the Earth, the human race would naturally not want it anymore, and beneath the surface of the Earth, they have dug, in order to cope with the natural environment as well as the cosmic environment, a series of large scale for hundreds of millions of years Huge underground tunnels as well as underground cities, they have no problem holding on there for thousands of years, and can return to the surface to rebuild after everything has passed.
The Empire took the Green Dragons' advice and attacked Earth using only asteroids, and the Human race, in shock and dismay, had no choice but to withdraw from the solar system, followed by the departure of the Imperial army, leaving only the green-skinned lizards hiding underground, waiting to see the light of day again.
unfinished business to be continued