Dragons, General

The Dragons are the most magically connected species across the multiverse. They may be killed but their deaths can change the world. When dragons are killed, especially old or particularly powerful ones, they may release waves of magic that can affect the world in wildly different ways. Some may warp the area around their death, some may affect their killers or the dragon may revert to an egg laying amongst its hoard. Whatever the case the death of a dragon can cause problems or solve them. 
In the modern day Metallic Dragons are generally accepted among the people of the world, with the exception of the Empire. The Metallic descendants of Bahamut are benevolent or at the least indifferent to the presence of mortals who are not attacking them. These dragons generally use their power to aid mortals in various ways in exchange for relatively small or meager rewards. 
Chromatic Dragons however have generally fallen from grace. Where they once ruled over lands they have since been driven out of civilized areas or even from entire planes. Most chromatics have devolved into feral beasts or given themselves to subservience as a means of protection. The few Chromatic Ancients that remain are incredibly powerful and lament the fate of their kind.
Gemstone dragons are an oddity, they formed from the mixing of Bahamut and Tiamat's spilled blood. They followed neither Dragon God and make their own decisions on the world, whether being of aid to mortals or a hinderance. The Gemstone Dragons are few in number and most of those who have survived to become Ancients are the originals of their kind. These Ancients generally dwell in their own demiplanes, content to care for their descendants and little else.
There are other less known dragon types but they deserve their own mentions. For now on the Life Cycle of Dragons:
Hatchling 0-5 years: Hatchlings are generally range from the size of a small dog to standing the height of a man depending on their age. They are almost harmless with their claws being to soft and short to be unable to harm most creatures and their breath weapon not being developed yet. They are ravenous and will devour any food placed within range of their mouth. Dragons of this age do not demonstrate intelligence until they reach their next stage of life.
Wyrmling 5-50 years: Wyrmlings are juvenile dragons, comparable to children that have not reached any form of maturity. They stand larger than a man and are fully capable of defending themselves from most common threats. A dragon of this stage may raid a town or village for food or shiny objects. Wyrmlings are capable of taking on humanoid form, with mixed results.
Young Dragon 50-500 years: Young Dragons are comparable to teenagers and young adults, they have emotionally matured and are intelligent enough to function completely on their own but lack the full maturity that comes with time. It is during this time that dragons begin showing the more unique traits of their scale, unique interest in objects for their hoard and unique approaches to problems. A young Dragon may claim a city and the surrounding area as its domain.
Adult Dragons 500-1500 years: Adult Dragons are the true dragons, Powerful and Majestic with the power that makes them legendary. Adult Dragons generally have established territory and will fight mercilessly to defend it as this is also the time in which a dragon may take a mate and raise young. These Dragons may be capable of magic or even be comfortable fighting in a humanoid form. Some have been known to secure their hoard and travel as adventurers. An Adult Dragon is powerful enough to claim an entire Kingdom as under its protection or even declare itself lord of a region. 
Ancient 1500+ years: The final Stage for most dragons, Ancients are among the most powerful dragons and can manipulate the world around them, even unintentionally. Ancient Dragons cease growing at this stage of their life and no longer require food or drink though they may still indulge. These Dragons will often be Legendary creatures though they may not be very active, as for most Ancients sleep among the treasures of their life or recounting the objects of their hoard may provide contentment. Ancient Dragons may act as protectors or the Sovereign Lords of regions, demanding payment for their service but rarely being seen. Though for some this may not be enough...
Great Wyrm 1500+ years and magic: Great Wyrms are the largest dragons, with the smallest on record being Saalima Khan and she stands nearly twice as large as an Ancient in her full size. Dartak the Hatred was thousands of feet from the tip of his nose to his tail, rivaling Tiamat in size. Great Wyrms are also among the most powerful creatures within the multiverse. Saalima Khan's breath causes storms to generate around her while it is said that Dartak's breath could raze entire kingdoms. While the exact requirements for becoming a Great Wyrm are not known, All Great Wyrm's besides Saalima were blessed by either Bahamut or Tiamat to achieve their transformation. The final notable Quality of Great Wyrms is that their scales are all Crystalline, not gemstone but true crystalike, hardened and thick they can shrug off most attempts to harm them with little thought.