Wendigo

Turn Resistance . The Wendigo has advantage on saving throws against effects that turn undead.

Near Blindness. The Wendigo has incredibly poor vision, only very barely able to discern large, general shapes and bright lights. It relies almost exclusively on its tremorsense ability. Creatures who do not trigger its tremorsense ability are considered invisible to the Wendigo, unless something on their person glows. Creatures casting spells with verbal or somatic components trigger its tremorsense ability.

Wimpering Host. The Wendigo's spirit possesses the body of a humanoid turned cannibal, but the host is still able to speak, though it is blind and deaf. The host usually wimpers about hunger, justifies its actions ("But I was just so hungry", "I didn't mean for this to happen", etc), or just bumbles madly, frequently repeating itself. While the host spirit has no control over its body or senses, it is in tune with the emotions of the Wendigo, especially anger and fear. When the host can feel the Wendigo fear for its life, usually in the presence of fire or in the heat of battle, the host will frequently scream out the Wendigo's weaknesses in hopes that some traveller can end its misery.

Regeneration. The Wendigo recovers 20 hit points at the start of each of its turns as long as it has at least 1 hit point. If the Wendigo takes fire damage, this trait doesn't function until the end of the Wendigo's next turn.

Lurking Predator. The Wendigo's preferred tactic is a series of surprise attacks of visceral intensity. The Wendigo has advantage on Dexterity (Stealth) checks when taking the Hide action.

Fear of Fire. As long as the Wendigo's Feeding Frenzy ability hasn't activated, it will never willingly subject itself to fire damage.

Fire Evasion. The Wendigo's primal fear of fire is always near the front of its demonic, bestial mind. When the Wendigo is subjected to an effect that would deal fire damage to it and that allows it to make a Dexterity saving throw to take half damage, the Wendigo instead takes no damage if it succeeds on the saving throw.

Feeding Frenzy. After the first time an enemy is reduced to 0 hit points in a fight, the Wendigo cannot benefit from its Lurking Predator trait, but gains an extra attack with its Claws when using its Multiattack action.

Multiattack. The Wendigo makes 2 attacks with its Claws. It can then use its Frightening Presence.

Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 15 (3d6 + 5) slashing damage. 

Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 8 (2d6 + 1) piercing damage plus 12 (2d6 + 5) necrotic damage and 12 (2d6 + 5) cold damage. The Wendigo heals for an amount equal to the amount of necrotic damage dealt this way.

Gore: Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 18 (2d12 + 5) piercing damage. 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 a DC 13 Strength check or take 72 (8d12+20) slashing damage, taking half as much damage on a successful save. Creatures above half their maximum hit points have advantage on the saving throw.

Frightening Presence. Each creature within 60 ft of the Wendigo that can see it must succeed on a DC 13 Wisdom Saving throw or be frightened for 1 minute. A frightened creature can repeat the saving throw at the beginning of each of its turns, ending the effect on a success. A creature who has succeeded on the saving throw at any point is immune to the Wendigo's Frightening Presence ability for the next 24 hrs.

The Wendigo can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The Wendigo regains spent legendary actions at the start of its turn.

Claws. The Wendigo makes one attack with its claws attack.

Bite (Costs 2 Actions). The Wendigo makes one attack with its bite.

Lurk in the Shadows (Costs 2 Actions). The Wendigo may take a free Disengage action followed by a free Hide action, provided its Feeding Frenzy ability hasn't activated yet. The Wendigo gains 60ft of additional movement.

Frightening Presence (Costs 2 Actions). The Wendigo uses its Frightening Presence.

Gore (Costs 3 Actions). The Wendigo makes one attack with its gore.

Whispering Madness (Costs 3 Actions). Each creature within 100 feet of the Wendigo must succeed on a DC 13 Wisdom Saving throw or gain a random effect from the short-term madness table. If a creature already affected by any madness effect fails the saving throw, it is charmed by the Wendigo. If a charmed creature eats humanoid flesh before its madness effect subsides, it becomes itself a new Wendigo over the course of 1d4 hours. A creature who loses its madness effect for any reason is no longer charmed. A creature who has succeeded on the saving throw at any point is immune to the Wendigo's Whispering Madness ability for the next 24 hrs.