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.

Hydrogius is a handsome Water dragon, and at first appears to be the carefree king of his lake domain. But one might wonder if he is truly happy, for he has a quiet sadness about him. He was reluctant to talk about it, at first, but later confessed that, while he will mate with the Den's females when required, he has fallen deeply in love with a wild female Skywing who comes to visit his lake regularly. Unfortunately, Hydrogius cannot fly nor walk on land, and while the Skywing could enter the water, she will not, for fear that she will drown. The Skywing is also wild and shy of humans and other dragons, and no amount of pleading has yet convinced her to allow him to seek help from Magi dragons or the Keeper, who would like nothing better than to see him truly happy.

Hydrogius has a slightly malicious sense of humor, and enjoys playfully tipping small boats with unwary human occupants when they fish in his lake, or brushing against the legs of swimmers.