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.

The Vampire Handbook: Book 4, page 95.

"Why Vampires do not go out in the sun."

"Vampires do not go out in the sun because they will burn and die. Also, the sun is bright. It could hurt their eyes, and then they wouldn't be able to see."

-Contribution by Wrench.

Let's make this simple: This Vampire is dumber than dirt (if dirt had brains, that is). He's currently mated to Totalitarian, who takes advantage of him in every possible way because of his complete lack of cunning. He never gets mad at Totalitarian; because despite being ruthlessly exploited, he's actually hopelessly infatuated with that cold-hearted vamp.

Also, the sun is bright.