Wendigo

Freya pressed her palm against the fort's doors. Her fingers skimmed past the scars--deep gashes in that old wood, as the fort door creaked open. The broken door bar slid against the dirt stopping the door just before it hit the stone archway, opening up then upon a dusty courtyard, the cold fog here unmoving, clinging to the earth.
The courtyard itself was devoid of motion. A smoking campfire and it's cooking pot lay still, A smithy and its furnace brooded darkly in a corner, and the door to the main hall and barracks ahead--slightly ajar. From the door, the mists seemed to pour out.
"They're gone." But as she looked down past that milky fog, vicera and oily stains sat just below her armored feet. Freya put her hand on the pommel of her sword, looking back at Ozdemir as he walked further in, past the stone archway.

A proper Wendigo, one fully transformed and without semblances of its prior sentience, is a deadly predator. Known most intimately in stories among villages that have suffered famines, a Wendigo is created when a person feeds on the flesh on its ilk--cannibalism. The transformation is first mental and slow; it starts as simple curiosity, formulates into a desire, and finally... the act, which when done once becomes much easier.
It is a common fact that cannibals, even when eating their kin, do not last long. Problems with the body develop--odd spasms and ticks, seizures even. Most who turn to cannibalism are killed by their own body. Those who die this way become proper Wendigos, as they rise from death with an insatiable hunger.

Predatory Behaviors and Hunting Patterns

He looked about slowly, eyes tracing the ground for footprints. He nodded finally, looking back to her. Freya walked forward, steps tentative and muffled in the clinging mists. Subconsciously, her arms pressed tightly to her sides for warmth. Her mouth opened, she inhaled as though to speak, but Ozdemir held up a hand, jolting his index fingers to his lips as his eyes looked toward the door of the main hall. The clatter of plate and cutlery resounded out from beyond the door. Using the moment's masking sound, Freya placed her free hand on her scabbard and slowly drew her sword, Ozdemir following in suit and he drew his spear.
They crept toward the door, Ozdemir ready at the door as Freya shifted back and forth while peering through the open sliver of the door. She swayed slowly, serpentine, until stopping suddenly, her lips pressed together, grip tense on the hilt of her sword, eyes wide but fierce. Slowly, without looking away, she shook her head--once. Ozdemir inhaled long and heavy, putting his palm against the door, lightly drawing it back and tapping it noiselessly.
Freya nodded, shoulders bunching up, a knee beginning to shake. She readied a free hand, and counted down.

Wendigos are clever hunters, able to use the ability to mimic any voice it has ever heard. Those who specialize in hunting Wendigos never speak during a hunt. This is due to the fact that many of those old hunting companies would venture out into those wild places after hearing the voice of one of their friends who went missing during the trip cry out. Recue missions now, are also forbidden for this same reason.
Wendigos have also been known to take the shapes of other creatures, most often appearing as a normal version of the animal, but without pupils, leaving a milky sclera staring out into the world. Most villages know of this form but do not associate this form with its true Wendigo form and instead most often refer to the form itself as a "Not" animal. The "Not Deer" and "Not Wolf" are its most common forms it takes.
Finally, Wendigos are said to leave no tracks. This is in part due to magical abilities this creature gains upon death as part of its Corruption into its accursed state. It is theorized that a Wendigo is actually unable to walk on the face of the world due to its unholy nature--even the wild mother herself rejects this beast. For this reason, perhaps, the Wendigo brings with it a cold fog that runs along the ground. The fog instead, it is said to walk on, and can use it to teleport anywhere within that cold mist.

Infamous Accounts of the Wendigo

They forced the door shut, a scream coming beyond the door as a force much greater than they rammed against the door. The frame buckled, the hinges cried out, the wood shrieked, all as if to warn them away. Another hit... and another, but Ozdemir and Freya dug their heels into the ground. For a moment, then finally, it stopped.
"Freya, the mist!"
Ozdemir's wide eyes pointed at their feet, then traced along behind them, Freya turning to watch as from that mist, it swirled and lifted up, into the form of tapered fingers with long pointed claws, spindled arms--its bone and sinew plain to see under that thin skin, blood-velvet antlers that crowned glowing and pupilless eyes, and howling icy hunger.

The Palewood Wendigo was a fearsome creature that stalked and marauded the outskirts of Cenodoxia. When that city fell and was refounded as Ievlen, the city's militia no longer had the ability to patrol the city's border and enforce it against the monsters that lived there. That Wendigo, skin blue and eyes a sapphire glow, as said to be the First Wendigo as there were no accounts of its death since it was first sighted, just accounts of survivors who later disappeared.
For months, it grew bolder and began to invade the city, taking unlucky victims back to its lair. As the government tried to piece itself back together, Edrin Theoril, founder of what would become the Blackguard, set out with his divine weapon, The Twelve Arms of Death, to slay the beast.
This proved to be the first account of this beast being slain.