Wendigo

The Wendigo is a spirit that devours, human flesh. The native Americans and other tribal people believed that eating human flesh granted powers, but eating too much of it made you become corrupted and something less then human. They have an ever lasting hunger, un-natural speed and strength. They are more than excellent hunters at night and in day time they're just a little worse. Their senses are stronger and they have claws and fangs. They can even mimic human voice. They are for the most part in-human and cannot be killed by weapons except maybe a flare gun. To kill it you must salt the body and burn it. The defense you have against it is probably protection or defensive magic like a magic circle.