Horse Dragons have equine-shaped bodies and hooves instead of claws, which allow them to be fast runners. They specialize in running takeoffs, which are quicker than taking off from a stand-still. Horse dragons are able to stalk their prey from the ground then quickly execute an aerial attack for the kill.

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.

"Shadowmere may seem like just a Horse dragon but she is a member of my family. She is one of us. Shadowmere is skilled greatly in the arts of murder and stealth and is a wonderful addition to our shady little clan." This is what TheNightMother said upon bringing young Shadowmere to the Sanctuary of the Dark Brotherhood, a group of assassin dragons. Shadowmere is a skilled assassin and enjoys nothing more than catching her prey unaware; she floats down from the skies, a herald of death on silent wings. Her target never suspects a thing.