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.

Bacico likes spending time where there are many swallows as he likes comparing himself to them, but doesn't feel the need to be the animal he resembles, not like his owner's other dragon, named Galloping Violy, who is a horse dragon. But Bacico mostly likes swallow company because he is the biggest and most colorful of them all, so he almost declares himself the king of swallows. Well, he would do it if swallows were intelligent and understood what having a ruler does mean. But because they are just birds following their instincts, Bacico forgets about his dream of being a king and simply has fun flying in the air and catching insects together with them.