Waterhorse Dragons received their name due to their horse-like physique and endearing behavior. They are capable of surviving out of water, and when on land their skin secretes a gelatinous goo to retain moisture. However, their large paddle feet are better suited for swimming, and waterhorse dragons tend to move very awkwardly when on land. Waterhorses are very friendly dragons and enjoy playing with humans.

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.

Haillii's mom was a wanderer, so her dad, Piesys and Moss raised her, and they were wonderful role models, well, most of the time anyway. Piesys swam with her whenever her dad was busy. She introduced her to a pod of dolphins which she quickly bonded with. They would even go on adventures, fishing tuna and fighting off sharks (much to her father's horror). When she was tired, Haillii would pull herself ashore and talk with Moss. He knew a lot about the wildlife and plants, both aquatic and land-ridden, and she was all to eager to learn.

When she grew up she decided to move, because she wanted to meet other dragons and decided to start off with the cave her dad had grew up in. There she meet another Horse dragon nicknamed Q. When she learned Q had never seen water she knew it was her duty to show it. She flew Q and it's friends to the beach she had been born on. After that they grew closer, and she began to regard Q as the treasured little sibling she had always wanted.