In Russian vampire lore being born the son of a werewolf or witch is enough for a person to become a vampire upon death. Of this type of vampire, the myertovets, just about nothing is known of its abilities or hunting techniques. However, what is known about it is the very specific way in which it must be killed: a stake must be driven through its heart in a single blow. Should the stake miss or the strike was not powerful enough to penetrate all the way through, the vampire will immediately begin to kill its attacker.

Source: Bogatyrcv, Vampires in the Carpathians, 127, 171; Ronay, Truth about Dracula, 23; Summers, Werewolf in Lore and Legend, 15

The Kashubian people of north central Poland are quick to baptize their children, for if one should die before the sacrament can be given it will return as a demonic vampire known as a mwère (“slowly”). Girls are particularly susceptible to this curse. It drains the life- energy out of sleeping horses and people by choking them to death (see ENERGY VAMPIRE). Should the victim reach out and successfully grab it, the demon will turn into a ball of HAIR or wool. If in shock the person should let go, the mwère will capitalize on the moment and vanish into thin air. The Mwère is the giver of nightmares and nocturnal emissions. It has the ability to fly through the night sky on a spinning wheel and can pass through the opening in a keyhole.

Plugging keyholes and keeping one’s shoes next to the bed at night keep the mwère from attacking. If in the morning a person’s horse is wet with sweat, it has managed to survive an attack from a mwére. Some lore says that when this is the case, the animal will sweat apples. The mwère is similar to other vampires, such as the ALP, INCUBUS, MARA, and the SUCCUBUS.

Source: Jones, On the Nightmare; Keyworth, Troublesome Corpses, 103-104; Perkowski, Vampires of the Slavs, 197