Hamrammr

The Hamrammr are Norse warriors with supernatural abilities. They wear animal skins to gain the animals power or form while in battle. The power of these creatures grows the more they kill and eat, and they can potentially get to the point that they are completely unkillable. Sometimes their very presence scared enemies off the battlefield. Often a Hamrammr attempting this would end up dying due to their overconfidence.

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.