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.

Vague grew up under the fog of her father's reputation. She heard stories, but never believed them. Kagerou was a wonderful, caring father, so she never minded the stories. Her mother, Grigio Ciel, she only sees every now and then, as she and her father are those of the sea, while her mother is that of the sky.

Her mother being half French, half Italian, Vague was named in French. Vague is French for 'Wave.'