Sunset Dragons are closely related to sunrise dragons. However, their behaviors differ greatly. Sunset Dragons generally live alone or in small packs. They are more active in the evening, hunting and performing all of their daily tasks as the sun sets.

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.

Miss Tsuki San is a sunset dragon. While she and Miss Iriai san are cousins and like sistersbest friends, she doesn't get along with sunrise dragons like Miss Dawn San. Miss Tsuki San prefers her last name to be just the suffix san, the one not meaning sun, because that would contradict her first name which means moon. It is not unusual to see Miss Tsuki and Miss Iriai telling each other scary stories to keep other dragons away. A lot of their stories involve gothic themes and gore, of course this is only done because they are a bit anti-social. Miss Tsuki though doesn't like sunlight because it hurts her eyes, so she usually sleeps through the whole day.