Dragons are not born; they grow from humans. When a human being is consumed by greed to the point that they wish for nothing else but to lie upon their hoard and possess it, then they will be transformed into a dragon.
Dragons hold no malice towards the human race, only fear and jealousy. When they terrorize the countryside they do so in order to strike fear into their enemies and secure the defenses of their hoard. Above all else they are afraid that a hero will come to take their gold away from them, yet this is the doom they bring upon themselves. They are compulsive; they cannot help themselves from committing violence even when they know it serves no purpose.
Some dragons are grown from dwarves, like Fafnir. Others are transformed not by their greed but their cowardice, becoming dragons after they flee into the distant wilderness. This was the fate of Val, Kott and Kisi, the princes of Gestrekaland who escaped from the wrath of Halfdan Eysteinsson. It is said that many dragons live in the far uncharted lands where men never go. Because there are no humans, they have nothing to fear, and so sleep soundly.
Dragons are pitiful creatures. They spend their time fretting, weeping, hating and counting their gold. If a single coin is lost after it has rolled under a rock, the dragon will fall into a black mood that lasts a year.
Dragons do not accumulate treasure after their transformation. They have forgotten the pleasures that gold can buy and care only for the gold itself. If anything is stolen from their hoard, however, they will pursue the thief to the ends of the earth.
There is one dragon with neither hoard nor lair; a monster called Nidhogg who gnaws at the roots of the World Tree. It is said that the world will come to an end when the tree dies. None can say who it was that became the Nidhogg, but to become such a beast he must have been guilty of the most terrible sin that the world has ever seen.
The axolotl is a neotenous creature, meaning that it reaches sexual maturity without metamorphosing into its adult form, the salamander. Millions of years ago, the axolotl was only the juvenile form of the salamander, but in time evolutionary pressures meant that the species stopped undergoing metamorphosis altogether. Nevertheless, the genetic material of the salamander remained hidden inside the axolotl. Under certain unusual conditions, or when treated with hormones in the laboratory, the axolotl can still undergo metamorphosis to become a new species that is functionally extinct.
Some scientists speculate that man is also a neotenous creature. He no longer has any need of his adult form, but under certain circumstances it is still possible for him to undergo metamorphosis and become a dragon. The nature of the dragon race, and why they became extinct, remains unexplained. However, the theory is supported by recent findings that show human and dragon genomes to be identical.