Count Tugarin
A Dark Dragon said to be the progeny of Tyr and Gorinych. He was born fully-formed, with the ability to assume a number of dragonforms. His horse Iglometcz was said to be able to take the form of a giant serpent, or a writhing mass of asps.
Tugarin was invincible in battle, but met his end in a celebrated old Scandish story that tells of how he was tricked and murdered by Brother Alexey, one of Vashilov's companions.