There are many legends of shapeshifters and lycanthropes in Celtic Mythology. Some of the oldest are based on the same concept as the 'bear'serkers of nordic/teutonic myth. Ancient Celts and Druids would don wolf skins to take on the attributes, and sometimes the form of the wolf. This picture is based on that practice. I call it Faol-Laoich. 'Wolf - Warrior'. Notice the wolf shaped woad painting on his face.