Humans

Despite how large and arguably much more powerful dragons and their society are, the human is something they fear very much. Humans are seen as violent lawless creatures. With their age, the dragons have seen war after war, extinction after extinction from their vantage point in the clouds. They are doing anything they can to protect their world from the same fate.

The magical force that surrounds the dragons realm plays a huge roll in this. Humans flying above the clouds, or going through a low hanging cloud will not see the dragons. There is a barrier at the bottom of the clouds, where humans would not remember flying through. To dragons, they lose vision for a few moments as they go through this layer of magic. Even outside their realm, this magic shields them. Fog gathers around them, the low atmosphere form of clouds. All humans would see would be a large deer with antlers. Or waving leaves on a bush. Nothing to indicate anything out of the ordinary. This is why many human folklore have been created in the fog, the presence of dragons.

The average human is as tall as an average dragons front shoulder. Dragons being slightly bigger than horses, not including wingspan.

Despite their unwillingness to interact humans have had a fascination with the concept of dragons despite the fact that no evidence has been found to prove dragons exist. Dragons are the themes of many stories, both good and bad. Because of this fascination, several dragons, form morphed into humans, spend a year in the human world monitoring what is being said. If any human has seen a dragon in any capacity, this is reported back to their kingdom as a "fracture event". That kingdom has the responsibility of communication such to all other kingdoms regardless of politics, as human awareness is something that effects every dragon. Fracture events are then handled by the founder kingdom, who can request assistance from surrounding kingdoms if needed. The kingdom can be put under internebular investigation if they fail to remove or otherwise deal with the fracture event. This is the one thing all dragons, all kingdoms, all realms agree on. No humans.

So keep an eye out in the fog. If you're lucky, you might just catch a glimpse of the end of a dragons tail, or a wing.