I tend to mess around with dragons quite a bit compared to vanilla 3.5. First, they’re truly ageless and usually ridiculously old. Old as in J.R.R. Tolkien old. Old like sitting on the porch with Galadriel and talking about how fast mountain chains get worn down by erosion old. Well, maybe not so many are as old as her, but at least a few are.
I also use vastly fewer than vanilla 3.5. In the whole of my world, there are maybe a total of 50 dragons. Of those only 10 are particularly big. Those from 40 pounds up to 150 pounds, are typically not "real" dragons but rather "drakes". A dragon’s egg would be about the size of a pygmy and the beast would grow larger than a horse in about two years. If that sounds fast, consider that great white sharks are born at about 4 inches long and reach 6 to 10 feet by the end of the first year. Whales grow at similar rates, especially the big ones. Humans and other primates are freaks who spend a bizarrely long time as children.
I do tend to stick to the powers and abilities of the dragons from vanilla3.5, but don’t expect the personalities to stay. So if you bump into a dragon with black scales, your well-educated character has every reason to assume it lives in a swamp, can spit acid and breathe underwater. On the other hand, assuming it is evil or cruel is a big mistake. So is assuming that it is weaker than a dragon with blue or silver scales of the same age.
That’s the general, let’s look at some specifics.
Dragons tend to think that they own the world. Humans disagree, but if you add up the land that humans live on, and then add up the land that reptiles live on, the dragons are in charge of about 35 times as much land as humanity and have a population that is tens of thousands of times larger. The core of humanity’s argument is that those are mostly animals, and the dragons themselves don’t really exert any authority over their spawn or the land the spawn occupy. The reality is that both species share much of the same land without really interacting with each other, so a human experiences humanity dominant, and a dragon experiences dragons as dominant. An outside scholar would almost certainly say that humans control a small chunk of the world very securely, dragons rule nearly the whole thing very securely.
Draconic history really falls into three phases broken by two major conflicts. First, they showed up spread through the world, established lairs and enjoyed hunting the giant dinosaurs. Then the first dragon war began when one of them, Jet, killed another dragon and animated its corpse, then decided that it would be a great idea to eradicate all life in the multiverse. The other dragons didn’t share her enthusiasm and lead by the great red dragon Maurgin proceeded to have a very long and nasty series of battles. Jet was backed by legions of her spawn, and the others had to duplicate the technique just to survive. Eventually she and the greatest of her offspring were locked away deep underground. Then came the second age where the dragon spawn spread through the world. The vast majority were mere animals and didn’t have any significant effect on the world. But a few were sentient and built cities and fought their own wars. In general the dragons ignored them. Eventually, Maurgin fell to pride and declared himself the lord of all the world and all the dragons in the world. He and three allies fought for quite a while, but one was slain, one fled the material world altogether (went into hiding in the demiplane of shadow), and one fled across the ocean. Maurgin was dangerous enough that the others couldn’t drive him off or even successfully invade his lands, but he eventually realized that he couldn’t take everyone at once either. So a cold war ensued. the third era is marked by the sentient dragon spawn being much closer to the dragons. Nearly all of the truly independent tribes were eradicated in Maurgin’s war, and the rest tend to look to the dragons as leaders. The sentient spawn populations are dramatically smaller than in the past, though they are simultaneously much more advanced culturally and magically. Into the void they left behind, humans have slipped. In the few thousand years since Maurgin’s war, the spawn slowly recovered and have finally begun to reassert themselves. Humans have already risen and fallen in that time, and the resurgent dragon spawn are embroiled in a conflict with them. It would have been completely one-sided except that the ancients "returned" and have caused quite a stalemate. The dragons themselves are largely sitting this one out, however Maurgin has recruited at least one new ally among the younger dragons, and has gone missing altogether. Because the others all fear him, they are watching much more closely since he dropped out of sight.
Dinosaurs and other reptiles are not at all related to dragons. Dragons were originally extraplanar. Dinosaurs and reptiles are native. That said, dragons have been very prolific at creating spawn and they now represent a decent 30% of the total number of animals in existence. Of those spawn, only a very few are humanoid. Most dragons have never created any spawn, and a few dragons have created dozens of species. Jet, one of the oldest and most evil of all beings, invented the technique and is the most prolific creator of spawn. In general, her spawn are custom creations of mine that use the "Shadow Spawn" title. Her twin sister is also fairly prolific and thus there are many Black Spawn species as well. The most common is the Black Spawn Sea Devil. Kasha’a Ree, is another prolific creator of spawn, and she is best known for the Green Spawn Hunters. Humans call those "lizardmen". Traditionally, there were two species of lizardmen: The hunters and another smaller tribe. In preparation for the invasion of the human lands, a new species of Black Spawn was created, named rather Brutes, but usually they are refered to as blackscales, because the other tribes all have greenscales. These are very large and very brutish. Unfortunately, they seem a bit tainted, and many of them are in fact evil. This causes great friction between them and the Green Spawn. Maurgin has a few tribes of Red Spawn who live in his mountains, but they are not participating in this war. What few Shadow Spawn live above ground are remaining in Jet’s old mountains. Humans have domesticated quite a number of unintelligent green and blue spawn used much like hunting dogs.
More specifics to come in the racial description of the Lizardmen and the Sea Devils as well as in specific entries for the different dragons who are known to the humans and lizardmen.