Vampire Dragons are members of the undead. They sustain themselves by drinking the blood of others. It is said that they are only “alive” at night, and seem dead or asleep during the day, as they cannot endure sunlight for long periods of time. Vampire Dragons can only reproduce by changing the eggs of other dragons, puncturing the shell with their fangs and injecting venom that kills the baby inside.

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.

There's nothing particularly strange about a vampire dragon choosing to live near the ocean, as there are plenty of coastal weyrs, after all. Even a vampire who likes to swim from time to time isn't especially odd. It's good exercise and a way to keep prey from escaping by taking to the water. Bykui, though, spends almost more time in the water than out of it, only returning to shore to sleep or to escape a bad storm. He preys on aquatic mammals—usually seals or dolphins, but he's one of the few vampire dragons ever to bite a whale. Bykui has always been more at home at sea than on land, perhaps because he started life as a deep sea dragon egg (and how his egg got bitten is a tale in itself).