Dorsal Dragons are so named because they have large fins along their backs that can be raised and lowered at will. They use these fins to regulate body temperature; they raise them to cool off when they become overheated. The bright colors on the fins double as a means of attracting mates.

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.

Herutsu is Japanese for "heart". Herutsu is a Dorsal dragon who reached full maturity on June 10th, 2010. Her egg was purple, black and gray striped and her adult body consists of all these colors as well as red eyes. Herutsu is sweet and playful but strong, fierce and protective when she needs to be. She is the daughter of dragons Aiicon and Herena and sister of Herona, all owned by Yuki-Chan.