When Water Dragons mature, they lose 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.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons 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. In Galsreim, dragons and humans coexist peacefully.

The close friend and rival of Dekai Hebi, Aguaryuu is a humble sea dragon of moderate power. He dwells in a large lake and enjoys swimming around on the surface, only diving deeper to meet with Dekai Hebi or to sleep in a cave near his friend's. He is kind and accepting of human life and is fiercely protective of human and dragon friends alike if the need arises. However, he is not easily riled as he has a calm spirit.