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.

His egg was found under the light of the full moon, having been kicked out of the den of a wild dragon, hence why he was named after the moon (tsuki is Japanese for moon). On top of that, when he hatched and his scales started turning colors, his underbelly was paler than most male vampire dragons, making him nearly glow when the light hit him. Tsuki is very shy, well aware that he was abandoned as an egg, and it has affected the way he saw other dragons. He always wanted to be accepted by other dragons, but due to how skittish he was, he constantly followed the one dragon he knew would accept him. He practically became Monstrum's (a fellow vampire dragon and head of the clan he had been brought into) shadow.