From Dragon Eye Atlas
Often considered the most majestic of magical creatures, dragons are both intelligent and powerful.
Similar to elves, dragons do not appear to be subject to old age and death through time. However, unlike elves they keep growing throughout their life, and the size of a dragon is a good indicator for its years. In fact, dragons grow slowly. After hatching from an egg the size of somewhere between a watermelon and a large wine barrel, depending on the size of the dragon that laid the egg, it takes them almost ten years to double in size and another 20-30 years before they become adults, at which point they will measure 5 metres from snout to the end of the tail.
A dragon ten metres in length can be assumed to be around a century old. Twenty metres, two or three centuries. Beyond that, rough estimates and guesses are all that even the dwarven and elven scholars have, because dragons beyond that size are incredibly rare.
The largest dragon, according to legends, was Grauch (Glauchimil in elvish) and he was said to have been 150 metres long, and is widely assumed to have been at least three thousand years old, and maybe twice that.
Dragons are highly intelligent creatures, though their thoughts and thinking are alien to all humanoid races. They are known to have a keen understanding of the smaller races' strategy, tactics and traps and many older dragons are able to understand and comprehend languages and texts. Some dragons are believed to have literally studied humans.
While dragons appear to be as varied as lesser races in their characters and motivations, vengeance is one of the few constant attributes connected to all dragons. Stealing an egg or injuring a dragon or killing or capturing a baby dragon or many other hostile acts are guaranteed to bring about fire and death, as dragons do not make a difference between humans, elves, dwarves, adventurers, peasants, armies or towns. When attacked they will retaliate against anyone and anything nearby, often burning entire villages or towns to ashes and laying waste to vast areas.
Dragons are used to be the apex predator of the world, so far above and beyond any other creature that the thought of non-dragon being able to defeat them seems to be difficult for them to grasp. Several dragons have been slain by humans, elves or dwarves because they were careless and acted haughtily.
Communication with dragons is tricky, even with those who know the languages of the lesser races, as their biology (throat, vocal chords) does not allow for human speech. If they communicate, they often do so through magic.
Despite their obvious intelligence, no discernible dragon culture exists. There are no buildings or other artificial constructions that are known or suspected to be made by dragons, they do not wear clothes or decorations, and they do not appear to have an equivalent of art or music, though some rumours claim that dragons sometimes sing or hum.
In much of their behaviour, they are simply large animals. One of those items is that they do not seem to have a conception of death. While they appear to mourn or at least miss others of their kind, they hold no funerals or other death rites, and do not seem to be concerned about what happens to the dead. They specifically do not seem to care if lesser races harvest dragon corpses and take their scales, claws and fangs or even eyes.
Dragons are intensely magical creatures. They use magic constantly for fine manipulations that their claws and paws are too large for, and are able to create delicate items with these "magical hands" as well as being able to use lesser races' items and even magical artifacts.
Many aspects of a dragon's life appear to be fused with magic abilities. Many scholars believe that by sheer muscle power a dragon would not be able to fly, and is instead supporting this ability with magic.
One ability that make dragons dangerous foes to those hunting them or in their way of hunt or vengeance is their strong and intuitive countermagic. While powerful magic is the obvious weapon of choice against a creature of such impressive physical abilities, most spells fizzle out or bounce off harmlessly and it takes a barrage of powerful magic to overcome the instinctive countermagic of a dragon.
Dragon Weapons and Armour
All dragons are covered in scales that are as tough as the best steel, while being light and flexible enough to not burden the beast down. As they are flying beasts, the legends about vulnerable bellies have no truth to them, though many adventurers continue to believe them. In fact, the scales are weakest near the joints, where more flexibility is needed, and on the wings where every weight matters.
Dragons have sharp teeth and claws, can use their tails as mighty bludgeoning weapons, and have considerable magic at their disposal whenever sheer physical dominance is not sufficient.
In the Dragon Eye system, a dragon has 15-25 points of natural armour, depending on his age and breed. The claw attacks of an adult dragon do 2d12 of damage, while a bite can crush even a fully armoured knight at 2d20/4. For juvenile dragons, these values are 1d12 and 1d20, while for ancient dragons they are 3d12 and 3d20. The tail lash of a dragon does 2d8/4 (1d8 for juveniles, 3d8 for ancients) of damage, but always counts as a heavy strike, not just on critical hits.
Their most feared weapon, however, is their fire breath. A dragon can spit fire from its mouth, an ability they use in nature to roast meat before consuming it and for igniting wood as heat is needed for their eggs to hatch. The cone of fire can extend to 50 metres for large dragons and typically does 2d10/5 fire damage, penetrating non-magical armour and igniting anything flammable hit. Juvenile dragons do 1d10 damage, while ancient dragons do 3d10 damage.
Dragons' abilities vary as widely as those of humans, though most dragons have a Melee ability of +2 to +4 and an Archery ability (used for the breath weapon) of +1 to +3. Their Sorcery ability is typically in the same range, while they are famous for their Insight, which is rarely lower than +3. Older dragons have often gained heroic dice as well, in any or all of those abilities.