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…