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 story of how Haku got from a lake to the ocean is somewhat of a humorous tale. Originally, he was sharing the lake with his elder sisters Serenity and Rose, and the three of them got along quite well. However, Ginji and Gliel were up to their old tricks again, and had the odd idea that it would be funny to move Haku to a bigger body of water while he was sleeping. The plan went well in the beginning stages, but it was when Ginji accidentally bumped part of Haku's body against a tree that things began to go wrong. Of course, Haku woke up and in his half-awake state, thought that he was being carried of by a large bird and struggled accordingly. Somehow, Ginji and Gliel managed to hang onto Haku long enough to get him to the ocean that was closest to their home. Haku is still angry at the two for this and takes great pleasure at dousing them with water during family visits.