Black Capped Teimarr are a small and sociable breed of dragon with an appetite for seafood. They can commonly be seen flitting around sand dunes and tidal marshes, searching for crabs and other aquatic invertebrates, or cavorting in tidal pools in hopes of finding landlocked fish. Because of their large wing-to-body size, they are excellent long distance fliers and are known to migrate hundreds of miles along coastlines, or even across open sea to outlying islands in search of seasonal delicacies such as bird eggs, fledglings and schooling bait fish. The males are easily distinguished by their large jousting horns and their extendable neck frill, which they show off to the females through enthusiastic head bobbing.

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.

Found in the Mountains of Elgar, Siaro's egg was discovered side by side with two others by the girl named Flight. Together with the other hatchlings, whose names were Crael and Swie, Siaro grew under Flight's care. When her wings first grew in, Siaro took the title "of the Guard" alongside her sisters (Crael and Swie). Together they felt it their destiny to protect those who could not protect themselves. As the High Family (a group of dragons whose goal is to take over Elgar) and their servants, the Posluga, became increasingly violent, Crael (the fighter of the three) urged the Guard to act. Under Siaro's orders, they followed the dark actions of the members of the High Family in secret until one fateful night when their spying was discovered. In the ensuing violence, Siaro witnessed the fall of her sisters before falling prey to her own doom. She is remembered as the leader of the Guard for her wisdom and understanding.