The most popular and most often thought of version of the dragon is that depicted in medieval Europe. This creature was described with the tail of a serpent, scaly bat-like wings, the claws of a lion, and the ability to breathe fire. Medieval Christianity used the dragon as a metaphor to describe evil, destruction, and Satan. The dragon was also a popular figure in tales: it was known to garner treasures and horde them in its subterranean lair. It would also kidnap fair maidens, who would have to be saved by a heroing knight that would normally slay the dragon, take the treasure, and live happily ever after.

Eastern dragons are often distinguished by the number of toes they have. In Chinese legends, the dragon is represented by the Lung, one of the Ssu Ling or elementals. Unlike its fire-breathing and malevolent cousin of Western tradition, the Lung represents the element of air and is described as a wingless serpent that can nevertheless fly; they are often represented as such and surrounded by water or clouds. Lungs represent the power of the emperor, were the bringer of good fortune, and brought on rains and floods. They were also said to be filled with immense wisdom, having the ability to foretell the future. In Taoism, they are the representations of the yang principle.

The early Greeks described dragons in several of their legends. For example, Ladon, who guarded the tree of the Hesperides and who was later resurrected to become the constellation Draco (the Dragon), is generally regarded as a dragon. The Assyrians' goddess of evil, Tiamat, was described as a three-headed dragon. Norse mythology also includes a repertoire of dragons; there, they were referred to as wyrms and were described as legless serpentine creatures that dwelt beneath the earth; a popular example of this is Fafnir, whom Siegfried fought to attain the wealth of the Nibelungs. Other examples of dragons include the Tatsu of Japanese mythology, the Apalala of Buddhist tradition, and the drake of Teutonic legends.

In modern fantasy, dragons are usually modeled after the medieval European version. Here, they are extremely varied in their characteristics: they can be knee high or larger than a building, and they can be human-loving or hero-eating. Their breath, while still often fire, can also be extended to a multitude of things depending upon the dragon's race; other breaths include ice, lightning, and poison.