[Kris on a Stick]

So let me explain. Back in the olden days of yore, when ACRONYM was still in its infancy, it was afflicted with a plague. And that plague was... DUNGEONS AND DRAGONS! Indeed, references to the damn thing were basically ubiquitous - exact spell names were used, links to the SRD were mandatory, and often used in place of actual description (gods forbid a roleplayer show any genuine creativity or writing prowess!), monsters followed their Monster Manual entries to a T, and any sort of deviation from the word of that spoooooooky Wizard who lives by the Coast would be met with disbelief, 'corrections' or even derision!
"Kris, you idiot! Kal can't be a devil, because he's part-Succubus, and in the Monster Manual, all Succubi are demons, and it is therefore entirely reasonable for my Pit Fiend to call him such and attack him for it! Also, it is wrong for Kal, the grandson of an Archdevil and the ruler of two Circles of Hell, to call my Pit Fiend a 'low-level flunky' because the Monster Manual specifically states that Pit Fiends are the generals of Hell's armies and the highest ranking demons around, and so I assume Kal is actually ignorant of Hell's hierarchy and/or lying."
No lie, this actually happened. So was it wrong for me, when confronted with the fact that there was no way I was going to play my Gold Dragon character the way they were written in the Monster Manual, I had a minor hissy fit and laid down the law of how I was going to play my dragon whether you guys liked it or not?
...
Probably, yeah. But for some reason, people (that is, people other than me, surprisingly enough) decided they liked my ideas, and so without further ado, I present you with...

OMG DRAGONS!

Yes, dragons! Flying, fire-breathing (except when they aren't), lizardy things. They're big, they're badass, and they have a really, really unhealthy obsession with treasure. Seriously, it's kinda creepy.
Here is a reference for all things dragon-y, at least as I will be playing them, along with the people shamelessly stealing my ideas (which of course, everyone is free to do, in part or in whole).
First off...

Types of Dragons

Spoiler

True Dragons

The real deal. True dragons are distinguished by their sapience, high intelligence, and their strong ties to the arcane. All true dragons are immortal, immune to both the effects of time and microbial disease (though magical diseases, inflicted cancers, radiation damage, toxins, poisons and the like all have their usual effects).
True Dragons are unique in their possession of Mysterious Dragon Powers^TM, their ability to convert Spirit into Mana, and use it to fuel a large variety of magical abilities. True Dragons tend to be large, with lizard like bodies. Most True Dragons have wings.

Terrestrial Dragons

The most common type of True Dragon, Terrestrial dragons tend to make their home in the material plane, hence the name. There are two main types of terrestrial dragon - Metallic dragons and Chromatic dragons.
Metallic dragons are highly social creatures. They often form large colonies of dragons, or else seek out other intelligent creatures, living in their cities and settlements, openly or in secret.
Chromatic dragons, on the other hand, are highly territorial and solitary. Though they often live in proximity to, and enjoy the company of other creatures, they are generally aggressive and mistrustful of other dragons, and will guard their homes zealously against perceived invasion.
Other than this, there are not many differences in between the two, especially not in terms of morality or ethics. Any one dragon, whether metallic or chromatic, is equally capable of cruelty or kindness as any other dragon.

Faerie Dragons

Fae Dragons. Pretty simple.
Faerie Dragons are often smaller than most other true dragons - some can be the size of a cat! They tend to be social and playful, at least with other fey, though like most fae creatures, they shun non-fey. Faerie dragons are highly in tune with nature, and often possess spiritual power similar to that possessed by druids, however, like all true dragons, they are still primarily arcane in nature.

Planar Dragons

Sometime you'll see a dragon... elsewhere. These dragons tend to be among the more powerful servants of their respective planes, assuming they are indeed servants and not free agents or environmental hazards, as many Infernal and Abyssal dragons are. Though they closely resemble terrestrial dragons, their bodies have often been warped to adapt themselves to their plane. Some dragons may be appear to be made entirely out of divine winds, sunlight, degenerate matter, Abyssal darkness, shadow, even pure Chaos. They also often have divine or spiritual abilities, occasionally granted to them by their gods, and their breath weapons tend to be tied to their plane in some way, whether in its substance, or by harming beings of an opposing alignment or orientation. However, like all true dragons, they will be primarily arcane in nature.

Elemental Dragons

Elemental Dragons are no less than the pure draconic manifestations of a given element. Earth, Air, Fire, Lightning, Water, Ice... yes, even Heart, though the other Elemental Dragons tend to laugh at them. Elemental dragons, much like ordinary elementals, are made entirely out of their element (Heart dragons are especially grotesque), and their breath weapons are tied to said element as well (how this works for Earth dragons have no idea.) Similarly their personalities can often be influenced by their Element as well, Mercury dragons are a pretty fluid bunch, Cesium dragons can be quite explosive at times, Chlorine dragons are particularly noxious, and Helium dragons tend to just sit there and do nothing.

Dracolich

Not a true species on their own, but significant enough to gain their own entry, dracoliches are merely dragons who have gained enough Necromantic power to turn themselves into one of the undead, usually after having been slain, though sometimes in order to pursue higher secrets. Terrestrial dragons most commonly become dracoliches, though occasionally Planar and Faerie dragons become dracoliches as well. Dracoliches typically retain all of the arcane power they had in life, though they lose their secondary breath weapon and often the ability to polymorph as well (though some dracoliches are able to turn into human liches). More often than not, their primary breath weapon becomes a caustic spray of shadow, instead of whatever element it was in life.

False Dragons

Pseudo-Dragons
A catch-all term for the many types of 'dragon' that aren't really dragons. Though they may physically resemble dragons in form, and often share traits with true dragons, including a fondness for treasure (some are even able to breath fire!), pseudo-dragons are differentiated from true dragons by their lack of sapience and arcane might. That's not to say they aren't intelligent, though. Many pseudo-dragons are canny opponents, the same way a cat or a crow could be, and many are the bane of smaller villages and towns. Pseudo-dragons range in size from smaller than a cat, to about the size of a small hill. They are not immortal, the way true dragons are, but most types are certainly long lived, with some living up to a thousand years or so.

Wyverns
Similar to Pseudo-Dragons, Wyverns are further distinguished from dragons by their unique physiology. Wyverns typically stand upright on two legs, though some crawl on four, similar to pterosaurs. Their main distinction is that the two forelimbs are extended and covered in a membrane to form large wings, instead of the wings being a separate appendage as in true dragons and pseudo-dragons. Wyverns, like dragons, are incredibly diverse creaturs. Some wyverns have a similar appearance to large birds, including beaks and feathers. Others live in large rivers and lakes (very few adapt to salt-water, unlike dragons). Wyverns typically are not able to breath fire, though some have chemical breath weapons, and most have venomous spines, fangs or stingers of some sort. Wyverns tend to have much shorter lifespans than pseudo-dragons, with few species living for more than a hundred years, and most with lifespans closer to 10 or 20 years.

Lóng
Commonly called 'Eastern Dragons', lóng, much like true dragons, are sapient, highly intelligent, immortal and capable of great feats of magical power. The primary difference lies in that while true dragons draw their might from the arcane, lóng are instead spiritual beings. Most lóng are manifestations or guardians of some natural phenomena, while others act as spirit guides, or servants of various gods. Lóng are typically serpentine in form, with fishlike overlapping scales and lion-like heads and manes. Lóng do not usually have wings, and can have either four, two, or no legs.

Mysterious Dragon Powers^TM

Spoiler

Much like Wizards and Sorcerers, true dragons are able to perform great feats of arcane power by channeling mana to fuel magical abilities. Unlike Wizards and Sorcerers however, who channel mana from the surroundings or leylines, whether through ritualized 'spells' or by sheer charisma, true dragons maintain their own inner reserves of mana, which they can draw upon at will. This reserve of mana enables true dragons to weave magic far more powerful than that of most wizards, though typically with less finesse, as they are drawing on a natural talent, rather than learned skill. Some dragons do study magic, however, becoming skilled wizards in their own right. Their inner reserve of mana also allows a dragon to activate his abilities and use magic in otherwise magically dead zones, and certain types of anti-magic field or other magic blockers, though this is quite rare. The downside of this method of casting is that dragons burn through their reserves rather quickly, and must replenish this mana store constantly (see diet). Also, certain spells, like Mage's Disjunction or specially enchanted weapons can destroy a dragon's mana store, rendering it 'helpless'.
Besides fueling arcane magic, a dragon's mana store also fuels two other important abilities - their primary breath weapon, and their natural ability to polymorph. All true dragons are capable of polymorphing into other creatures smaller than themselves, including some forms of complex protists, such as oozes or slime molds. Additionally, all true dragons are capable of reproducing with any species they are capable of polymorphing into naturally, producing half-dragon offspring (half-dragon oozes, why not!). Dragons are also, of course, able to use conventional magic to polymorph themselves into a wider variety of living things, including plants and bacteria, however they are not capable of reproducing in this state. So no half-dragon palm trees, sorry.
When polymorphed, a dragon retains all of its mental faculties, but is limited to the physical capabilities of the form it inhabits, including the loss of its breath weapons. However, they are also able to temporarily override this limitation, accessing their full strength no matter what size they're in, at the cost of mana. You have not lived until you have seen a jellyfish lift a boat out of the water and then reduce it to ashes with its flaming breath.
Speaking of breath weapons, all dragons have an elemental breath weapon, that is primarily magical in nature. In the case of terrestrial and faerie dragons, the element of any individual dragon's breath depends largely on their temperament. It is true for example, that Red Dragons, by nature, tend to have temperaments leading to fire breath, thus leading to the common belief that all Red Dragons have fire breath, however this is not necessarily the case. In planar and elemental dragons, their breath weapon will relate to their home plane or element.

Dragon Biology

Spoiler

You know it. Large, lizard-lizard like, big wings coming out of their back. Most dragons have ribbed, vaguely bat-like wings, however some dragons have irregular wing structures, including some aquatic dragons even having sail-like or fin-like wings in order to swim better. Faerie dragons may have normal dragon wings, or in some cases butterfly or dragonfly wings. True Dragons, unlike their close cousins the wyverns, do not usually possess venomous spines or fangs. However, many terrestrial dragons, including faerie dragons, have a secondary breath weapon, usually chemical based, such as anesthetics, sedatives, paralytics, or even narcotics and hallucinogens. Unlike a dragon's primary breath weapon, which is a Mysterious Dragon Power^TM and varies from individual to individual, secondary breath weapons follow the rules of inheritance and are passed down through families, with especially unique or potent chemicals becoming strongly associated with certain families, such as the Deime family and their potent fear-inducing hallucinogenic breath.
Most true dragons start off life as a hatchling, about the size of a large cat. Among terrestrial dragons, metallics are more likely to raise their young, alone, in pairs, or as a colony, as opposed to chromatics, who often leave their young to fend for themselves. Hatchlings grow relatively quickly until about the size of a draft horse (tail not included). At this point, they undergo a brief growth spurt until sexual maturity when they are usually about the same length as a whale shark. They continue growing at a decelerating rate throughout adulthood, until their growth rate reaches about a centimeter per year. Despite this, dragons never stop growing. Very rarely, dragons can grow to become as large as a mountain or more, and there are legends of dragons billions of years old (who have inevitably left the material world for the outer planes, where it is more spacious) with sizes rivaling that of whole continents, or even planets.

Diet

Spoiler

But now, what do dragons eat? Well, it's kind of complicated, actually. A polymorphed dragon will only need to eat as much as his form needs to eat. As for dragons in their true form? Oh damn. An adolescent dragon is the bane of farmers everywhere - many are not above stealing vulnerable livestock to feed themselves through this turbulent phase. And it just gets worse from there. As dragons age though, their bodies slowly become more and more infused with magic, slowly destroying their need to eat as they sustain themselves on arcane energy alone. Paradoxically, a mountain sized dragon eats even less than a shark sized dragon... and the continent sized ones seem to be able to sustain themselves on thought alone...
Or not quite. Because there's a second reason dragons eat, and it's this reason that gives so many of them their poor reputation. Spirit. Life force. Dragons feed off it, and convert it into mana. It sustains them and satisfies them, beyond the simple proteins and fats their prey made of. It is the reason even the most benevolent of dragons must eventually kill living prey, or leave itself at a permanent disadvantage. And it's also the reason why, more often than not, dragons like to prey on man more than any other creature. All Life force is not equal after all, and it's pretty safe to say that any sapient creature is more Spirited than a cow or a sheep. Oh, and it gets worse. Because after all, what can be more Spirited than a regular human?
...
Virgins, of course!
...
And you get double mana if they're a princess.