Doppelgänger
The Doppelgänger is an entity from German myth. The name translates to “double walker” or “double goer.” They appear as a shadowy double of the person who sees them, and it’s often believed everybody has one, most often invisible and without power or will. When they are seen, it is almost solely by their real counterpart and in a shadow or reflection moving in a weird way. They are sometimes evil, but more often are benign. In some rare cases they may be helpful. They sometimes manipulate the real person into doing evil and may separate from the body as the real one sleeps to go commit misdeeds. They may whisper into their counterpart’s ear to cause them to go insane. Sometimes the Doppelgänger appears as an omen of death or as a warning of upcoming danger.
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.