Erestun/Xloptuny

The Erestun is a form of spirit from Russian myth. They possess someone who is on the brink of death, often causing accidents, illnesses, or violence. They are thought to be the spirits of evil sorcerers formed when the sorcerer splits its soul, or when they somehow lose their physical body. They enter the body in an invisible astral form and cause what appears to be a miraculous recovery. They need to feed on human blood to maintain control of the body they possess and prey on the friends and family of their host. Sometimes they take only a small amount of blood, but in desperate situations, they will drain all the blood from their victims. They can be removed from a body through exorcism, though it must be altered as the Erestun isn’t a demonic entity. They can also be stopped by cutting off the person’s head, staking them, and burning them. This kills the host, but both options often do.

Citations:

Maberry, Jonathan. Vampire Universe: The Dark World of Supernatural Beings That Haunt Us, Hunt Us, and Hunger for Us. United States, Kensington Publishing Corporation, 2006.