Sorry, no more chain posts I swear.
Jürgen Hubert said:
It might be fun to consider alternate ideas about heredity and evolution other than the standard "genetic" explanations.
For example, what if changes to the body and mind during life could be inherited? Cripple a man, and the children he sires later on will be born with weak limbs. Put some curse on him, and the curse will be inherited. On the other hand, if you make a women beautiful through a spell or alchemy, her children will also inherit that beauty.
Such things could explain many "dark races" - they are descended from humans who were brutally tortured and stunted until their descendants reached their current appearance. Owlbears, gryphons, and other hybrid races could be the result of someone grafting animal parts on different animals. And so on...
This could be an interesting dynamic for one way in which magic works as an evolutionary force.
Perhaps this occurs as a component of adopting magic into your process of sexual selection. Intelligence thus becomes a means of manipulating this process.
Dragons could thus be super sexual selectors within the limits of sex-magic. This has a four fold effect:
1.) They can breed with anything as long as they get the ritualized aspects right.
2.) They can preserve, edit, and transmit an astonishing number of magic traits. Draconic reproduction is amazingly difficult but also incredibly successful on levels our primitive idea of sexual reproduction and selection can't even envision.
3.) When they get it really right they can produce tailor made children. Thus Bahumut and Tiamat aren't gods, they are actual progenitors of whole lines of draconic awesomeness. Sexual craftsmen par-excellence.
4.) Insane things: Maybe dragons are able to pick up traits from children. Swallow memories and magical capability. Meditate their way into advantageous traits. And so on and so forth.
Go mad with this:
Make Dragons the most succesful plants in history. Things which were around at the initial emergence of animals, and which have been selecting the very best traits from the animals around them and the things that happened to them ever since.
Dragons aren't a dying species, they're a rare and deliberate, at this point, meta species. Theoretically a dragon that went to another world and found even a bit of life and the right material to frame the magic could reproduce whole ecologies.
Possibly - you could kill the last dragon and under the right magical circumstances their genes would reformat themselves from the Bacterial and viral layers and just start making dragons out of the best local wombs or forests.
Possibly - Your setting doesn't have gods, but given enough time Dragons would actually get there.
Possibly - It's not going to be trans-humanism, it has always and already been trans-dragonism.