Unseelie Wendigo

Ambush Expert. The Wendigo gains advantage on attacks rolls it makes on a creature it has ambushed and surprised.

Mimicry. The wendigo can mimic any sounds it has heard, including voices. A creature that hears the sounds can tell they are imitations with a successful DC 16 Insight check.

Pounce. If the Wendigo moves at least 20 ft. straight toward a creature and then hits it with a claw Attack on the same turn, that target must succeed on a DC 13 Strength saving throw or be knocked prone. If the target is prone, the Wendigo can make one bite Attack against it as a Bonus Action.

Natural Sluther.  The Wendigo has advantage on Stealth checks when they are obscured by foliage.

Multiattack. The wendigo makes two attacks: one with its bite and one with its claws.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 4) piercing damage. On a hit, the target must succeed on a DC 13 Constitution saving throw or take an additional 9 (2d8) necrotic damage. 

Claws. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) slashing damage.

Frightening Appearance. As a reaction, the Wendigo can instil a deep, primal fear in a creature that sees it within 30 ft, and that creature becomes Frightened. This effect is only removed once the Wendigo has been slain, or if it passes the effect onto another creature.