Swallowtail Dragons are graceful and quick flyers, much like their namesake bird. They are capable of precise aerial acrobatics, and can reach very high altitudes. Because of this, humans observing these dragons are often astonished at how large they are when confronted up close. A Swallowtail’s diet consists of insects and small mammals plentiful in temperate forests. These dragons are also made remarkable by their paper-thin wing membranes, which allow light to pass through, creating an astonishing effect on starry nights.

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.

Still little more than a hatchling and one of the youngest members of the Periodic Clan, Beryllium is often not taken seriously because of her age and fragile looks. Don't be fooled, however. She's tough and hardy, even a member of the Clan's army, and her flying skill rivals that of Titanium, the Guardian famous for her surprising speed and grace in the air. Hard on herself as well as others, Beryllium usually has little tolerance for delicate flowers such as Caesium, and she feels no need to sugarcoat her harsh criticism. Her overall impatience and alarming lack of empathy make Beryllium rather unpopular with most of the Clan's members, although she does have a rarely shown sweet side. Her brother Magnesium has discovered that it can be brought out using one of her weaknesses—green rock candy.