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.

Fao of Blue is an abnormally large Water Dragon. He is permanently settled in a cave underwater near the cave where his master's other dragons reside. His fins are taller and longer than most other Water Dragons' fins, and are also less transparent and darker. He seems to care and take more notice of Keyoshii, but is torn because Keyoshii's heart belongs in the skies while his is settled at the lake floor.