Dumbest thing ever is trying to classify historical dragons (as in dragons found in real life myth) by D&D terms. You have no idea about dragons, none.
The thing about D&D is that it uses a 19th century anthropologist/'natural historian' register to talk about a fantastic world on its manuals, and it's something that when it's well done can be really creative and unique and also can spark some really interesting conversations.
But since D&D has become, by far, the most influential and popular expression of fantasy in current times (perhaps not literature, but most fantasy people interact in videogames, etc. is directly influenced by it), the register and tone it uses (classifying everything in game terms and in a 'scientific' way) has become widespread, which means that some of the magic of fantasy, including supernatural things that cannot be defined in gaming or 'scientific' terms, falls through the cracks.
Like dragons.
You CAN classify dragons in your fantasy setting. I would be delighted to help you. I got a 10 in Vertebrate Biology. I can tell you all about how dragons might have evolved.
But a dragon is a symbol, it's something supernatural. If you're including dragons as part of your fantasy ecosystem, you have to think about what role they occupy in your setting. Are they just some kind of really big megafauna, or divine beings?
Spec-evo proposal: "really big megafauna" & "divine beings" are inextricably entwined categories, because the only way for a species to get Really Big without running up against hard physical constraints* or implausibly high resource requirements is by developing specialized organs that magnify the Spark of the Divine that exists within every living thing. The aforesaid Spark is here an objective biological fact, because during the Titanomachy at the beginning of the world, the rains of divine ichor & corpses of dead gods that fell into the primordial seas were the source of the organic compounds from which mortal life developed. Sparks of the Divine became endosymbionts, like mitochondria, living inside every cell.
* Something something square cube law, I'm not a scientist and I'm just going stream-of-consciousness here, sorry.
In most cases, the Spark organelle just smooths things over a little bit, providing the scientific justification for anything that might have to be explained as "well it's just magic i guess" or "maybe a wizard did it".** Species that evolve a way to magnify the Spark are liable to develop other implausible abilities over time in order to leverage the excess of divine energy they now have available to them. It is possible that they will then develop more effective ways to magnify the Spark in order to fuel those abilities, in a kind of positive feedback loop that, on long evolutionary timescales, bootstraps them from "animal" to "animal with some weird tricks" to "creature of magic" to "semi-divine being" to "actual god".*** This is why dragons can not only be implausibly large flying lizards, but also breathe fire, develop advanced intellects, &c. &c.
** This is how, e.g., something as heavy & non-aerodynamic as a pegasus can fly, or a twenty-foot-tall giant can walk bipedally, or unlikely hybrids like manticores can come into being.
*** There may be a point in this process where the organism in question has the power & intellect to start steering or accelerating their gradual apotheosis -- either on an individual or species-wide basis -- or there may not be. It is possible to reach full godhood without actually developing sapience or an understanding of what godhood is.****
**** Put this in your D&D setting to allow a Cleric of Giant Slug. Giant Slug has no commandments or doctrine; it's just a species of really big slugs. One worships them by attuning one's own Spark to theirs, which mostly involves studying them, interacting with them, & engaging in Slug Behaviors when practicable. Giant Slug does grant spells, but as, like, a reflex -- the slugs have no understanding of what they're doing, but autonomic processes leverage divine energy to benefit Giant Slug, & due to the nature of divinity this includes the empowering of worshippers.
The biological existence of the Spark is the explanation for all supernatural abilities observed in fantasy organisms -- including humans, because all magic is either consciously or unconsciously manipulating... wait hang on this is just midi-chlorians post cancelled






















