Krsnik/Kresnik

The Krsnik is a monster hunting creature from Croatia. They are thought to be the only creature powerful enough to oppose the Kudlak. They are born with a caul, which would either result in Krsnik or a Kudlak. Krsnik quickly become aware of their own nature and seeks out evil to combat. It is often believed every community would have one Krsnik and one Kudlak. They are thought to have the ability to shapeshift and often takes the form of pigs, oxen, or horses, typically with a white coloration.

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.