Horse Dragons have equine-shaped bodies and hooves instead of claws, which allow them to be fast runners. They specialize in running takeoffs, which are quicker than taking off from a stand-still. Horse dragons are able to stalk their prey from the ground then quickly execute an aerial attack for the kill.

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.

As a little egg, Thrill laid abandoned in the Cave. Then a curious horse dragon called Thestrala sniffed this little egg. Much to the older dragon's surprise, the egg smelled familiar. Thestrala took the egg home. One warm day in the summer, Thrill hatched and soon nuzzled her grandmother.

As a grown dragon, Thrill is normally cheerful, probably due to her Yule lineage. She likes to prance around which reminds her grandmother of a certain Yulebuck. She also likes to eat berries and fruits as well as meat. Sometimes, she has even gone as far as to hover for a far off apple. Once, she had accidentally caused an apple to fall and hit a man who was sleeping underneath the tree.