This is just a brief look at Slavic mythology and just the different names that were once believed in and the myths of some of the creatures. It's interesting and this article may want to lead someone to read more about this kind of mythology.
Belboy was known as the god of light, Dilwica was the Serbian goddess of the chase and Chalkychi was known as a flying demon. Lore has it that these creatures were huge purple beasts and had 12 wings and a head like a crocodile. For bread makers, Dugnai were household spirits that would help the dough rise.
The Dvorovoi was depicted as an old man with a grey beard and he was said to have been covered with hair. He was the spirit of the farm. Dzewana was the goddess of the moon and Khors was god of hunting and health. He was always depicted as a stallion. Lyada was known as the war god and Siva was the goddess of love.
Lesini Zenka, was known as a female woodland spirit and Ludki was a Serbian benevolent dwarf. Peklo was known as the underworld and Srat was a creepy flying demon. Upir was the name for vampire in Slavic myths and the son of a vampire was called, vampirovitch. Morana she was the goddess both of winter and death, which makes since because most trees and other natural things withered during winter.
So that's a brief look into some Slavic myths. To read more about them just click on this link: S. Myth and also check out at your local bookstore and library to find more on mythology books.