Dark Feast. A Wendigo can consume enough of a dead or unconscious Humanoid in 18 seconds (3 rounds) to fully heal itself.

Improved Critical: The Wendigo's attack does a critical hit on the rolls of 19 and 20.

Mimicry. The Wendigo can perfectly imitate any animal sound  or humanoid voices it hears, as loudly as it wants. Wendigo can emit a call for help or sounds of wild game to bait it's prey away from the group or settlement. If possible, Wendigo tries to stalk a group to learn voices of it's members before luring them to their doom. Though, in desperation, wendigo can confront a group head-on. In such case it tries to stun as many enemies it can with it's roar, snatch most defenseless member of a group and retreat to a safer place to murder and devour it's victim.

A creature that hears the sounds can tell they are imitations with a successful DC 20 Wisdom (Insight) check.

Natural Disturbance. A Wendigo can cause intrusive thoughts, hallucinations, or force creatures within 200 feet to look through it’s eyes at will, often viewing themselves or their group from a distance. If the creature can physically see the Wendigo, it can no longer influence them in this way.

Territorial Pursuit. The wendigo can sense any creature that is within 1 mile of it as long as that creature is on the same plane of existence.

Ancient Resistance. If the wendigo is targeted by a spell of natural magic, the spell instead fails and the wendigo succeeds any saving throw, taking no damage.

Abyssal Invisibility. The Wendigo is invisible when obscured by foliage, heavy rain, falling snow, mist, or other natural phenomena.

Ambusher. In the first round of a combat, the wendigo has advantage on attack rolls against any creature it surprised.

Elusive. If a creature opportunity attacks the wendigo they have disadvantage on the attack made against it.

Regeneration. The wendigo regains 30 hit points at the start of its turn if it has at least 1 hit point. If the wendigo takes fire damage , this trait doesn't function at the start of the wendigo's next turn.

Abyssal Echoes. The Wendigo Releases a horrid Scream. forcing all creatures in a 60 ft. radius must make a Wisdom Saving Throw DC 17. Any Creature that succeeds this is immune to this effect for 24 hours.

Multiattack: The wendigo makes three attacks: one with its bite and two with its claws. If it can it will use a Gore attack instead of a Claw attack.

(Bite) Devouring Flesh: Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 16 (3d6 + 6) piercing damage and 10 (3d6) necrotic damage. The wendigo bites a chunk off its prey and swallows. It regains hit points equal to necrotic damage dealt.

(Bite) Feed The Hunger: Melee Weapon Attack: +14 to hit, reach 5 ft., one grappled humanoid. Hit: 16 (2d10+6) piercing damage, plus an additional 16 (4d8) cold damage. The wendigo gains temporary hit points equal to the damage done. While the wendigo has temporary hit points, it cannot use this attack again.

Claw: Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 25 (3d6 + 6) slashing damage. If the target is a Large or smaller creature that the wendigo already hit with two claw attack this turn, the target is grappled (escape DC 16). Until this grapple ends, the creature is restrained and the wendigo can't use its claws against another target.

Gore: Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 19 (2d12 + 6) piercing damage. The Wendigo must have some form advantage in order to use its gore attack. If the Wendigo succeeds on two Gore attacks in the same round it will attempt to slice the target in two. The target must succeed on an opposed Athletics vs. Acrobatics check or take 64 (8d12+12) Hit Points damage.

Abyssal Creature. The Wendigo is an abyssal being that does not exist in the real world fully. Because of this they can enter the ethereal plane at will. Or force another creature into the ethereal plane.

The Abyssal Wendigo has 3 Legendary actions that it regains on the end of it's turn.

Abyssal Echoes. (1 Action) The Wendigo Releases a horrid Scream.

Claw attack. (1 Action) The Wendigo Attacks with a claw attack.