Wendigo

A Wendigo is a mythical creature appearing in the mythology of the Algonquian people. Wendigo's were former mortals, which is why they can transform into a mortal.It is a malevolent cannibalistic spirit which can transform into humans, or which could possess humans.

In Algonquian Mythology
The Wendigo is part of the traditional belief systems of various Algonquian-speaking tribes in the northern United States and Canada, most notably the Ojibwa/Saulteaux, the Cree, and the Innu/Naskapi/Montagnais. Though descriptions varied somewhat, common to all these cultures was the conception of Wendigos as malevolent, cannibalistic, supernatural beings of great spiritual power.

Wendigos were embodiments of gluttony, greed, and excess; never satisfied after killing and consuming one person, they were constantly searching for new victims. In some traditions, humans who became overpowered by greed could turn into Wendigos; the Wendigo myth thus served as a method of encouraging cooperation and moderation.

Wendigos were said to be giants, many times larger than human beings

Human Wendigos
All cultures in which the Wendigo myth appeared shared the belief that human beings could turn into Wendigos if they ever resorted to cannibalism or, alternatively, become possessed by the demonic spirit of a Wendigo, often in a dream. Once transformed, a person would become violent and obsessed with eating human flesh. The most frequent cause of transformation into a Wendigo was if a person had resorted to cannibalism, consuming the body of another human in order to keep from starving to death during a time of extreme hardship or famine.On one level, the Wendigo myth thus worked as a deterrent and a warning against resorting to cannibalism; those who did would become Wendigo monsters themselves.

Shape-shifters
Wendigos originally lived in the Northern part of Canada and the Uniited States but after being exposed they ran to United States to a new land. When they arrived back to Forks they had discovered that another tribe had already claimed the land. The Wendigos tried to force the Quileute tribe to leave or be eaten but the tribe refused. When the Quiluete men changed into Shape-shifters the Wendigos recruited and left. The Wendigos stayed hidden, stalking the tribe's people until they were ready to attack. Until one day they ambushed the tribe and ate the heart of most of the tribe members. In the end of the war the Shape-shifters managed to recaim the land. The Wendigos vowed to keep fighting to retrieve their land.

When Zachary was born he took the lead of his kind to fight for the reclamation of their land.