Wendigoes are monsters or spirits Willow had heard about back when she was still a teenager. One of her friends was a gaming nerd and came across this horror game on these creatures. Creatures that evolved from humans into monsters.
From what she knows, they are cannibals that feast on human flesh and anything else that moves during the winter when food is the most scarce to come across many years ago. Then, every few years or so, they would come out and hunt in the forest where there is hardly any game to be caught.
According to legends, they began as humans that were either lost in the woods or lived in the woods where they would have to rely on game meat to survive. However, when desperate, those people become vulnerable to desires and may even kill their own kind just to survive. This cannibalistic behaviour over the years would slowly morph their body structure into a monster-like form.