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.

Yuki Kuran is a vampire dragon, but she is not aware of this. Yuki was raised by Sophie Mouski and Shade Ark, who allowed her to drink their blood to survive. However, they never realized that Yuki didn't know that she needed the blood that they offered. She is convinced that she is not a vampire, but a normal red dragon. This causes others to either tease her or pity her. And so, Yuki hardly ever left Shade and Sophie's home. However, this changed when she met Zero Kirryu, a vampire who hates himself. She formed a friendship with him, and now they spend their endless nights and their sleepless days together in darkness. Yuki has fallen for him, but is unsure of how to tell him about her feelings.