Dragons are creatures with nearly unlimited life spans. They can survive for long periods of time, and no one has found a dragon that has died of old age. Adolescence is usually marked by the growth of a hatchling's wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. Once they hit adolescence, hatchlings change quickly, maturing to their full forms in only 2 years.

Dragons don't communicate with each other verbally, but they will growl to scare off predators and frighten prey. Young dragons will emit an extremely high-pitched squeal when they are frightened. To communicate, they use telepathy with each other and to speak to other creatures.

When water dragons mature, they lose their legs and the ability to survive on land, entering the water permanently. They are adept swimmers and eat whatever fish are in the lake they live in. They tend to inhabit the same lake for their entire lives, although a few live in the ocean and swim all over the world.

Hiromi is the fourth oldest dragon of clan Chiyo and, by far, the largest and strongest of the clan's many water dragons. This vigilant female constantly patrols around her clan's massive territory through the calm waters of the circular Guardian Lake. She has all life in the lake as well as the surrounding animals and human villages looking for signs of trouble. This method has allowed the rescue of many hatchlings and eggs as well as stopped many a human from crossing the lake to steal dragon eggs which, if they had succeeded, would have probably gotten themselves killed by the resident vampire, Sangsue.