Wendigo

Aura of Starvation. A creature that starts its turn within 10 feet of the Wendigo must succeed on a DC 15 Constitution saving throw or be consumed by a gnawing hunger for 30 seconds, resulting in Disadvantage on attack rolls and saving throws. A creature can repeat the saving throw at the conclusion of their next turn, ending the effect on a success. On a successful save, the creature fights off the hunger and is immune to the Wendigo's Aura of Starvation for 24 hours.

Aura of Fear. At first sight of the Wendigo, its massive, twisted presence generates an overpowering aura of terror. Each creature must make a DC 12 Wisdom saving throw. On a failure, the creature becomes frightened for up to 1 minute. The creature may re-roll the save at the end of its turn. On a save, the creature is immune to being Frightened by the Wendigo for 1 minute.

Magic Resistance. The Wendigo has advantage on saving throws against spells and other magical effects.

Mimicry. The Wendigo can mimic any sound it has heard, including voices. A creature that hears the sounds can tell they are imitations with a successful DC 12 Wisdom (Insight) check.

Mimicry. If the Wendigo can moves at least 20 feet straight toward a creature and then hits with a Claw Attack on the same turn, the target must make a DC 13 Strength saving throw  or be knocked prone. If the target is prone, the Wendigo may make one Bite Attack against it as a Bonus Action.

Mask of the Wild. The Wendigo can attempt to hide as a Bonus Action even when it only lightly obscured by foliage, heavy rain, falling snow, mist, or other natural phenomena. 

Spellcasting. The Wendigo is a 4th-level spellcaster. Its spellcasting ability is 20. The Wendigo has the following Necromantic spells prepared:

Cantrips (at will): Hunger. On a successful Bite Attack, the Wendigo can cast Hunger as a Bonus Action passing a curse to the target on a successful hit. While cursed, the target suffers from overpowering hunger, and must consume at least one quarter of a pound of animal-based food every minute as an Action or take psychic damage equal to its proficiency score. When the target begins their turn, if they can sense food nearby, they must make a Wisdom saving throw (DC 16) to resist compulsively seeking it out and consuming it as their turn. Any substance that is even barely edible is counted as food for this effect, including things like soft leather, intestine rope, or other things not typically considered food. Creatures that don't need food to survive (including creatures for whom eating is physically impossible) automatically succeed. On a success, the target is immune to this effect for the next 30 minutes.

1st level (4 slots): Hunger of the Damned. [Range 60 ft.] On a successful Bite attack, the Wendigo can cast Hunger of the Damned as a Bonus Action. The Wendigo locks eyes with the creature, and the deep black in the eye holes in the Wendigo's skull flicker momentarily red. The target hears a horrifying cacophony of slurping, chewing, crunching, swallowing, and all manner of grotesque eating noises that wrack it with psychic pain. The target must make a Wisdom saving throw (DC 16). On a failed save, it takes 3d6 + 4 psychic damage and is incapacitated for 30 seconds and can only communicate in unintelligible screams of horror and disgust. The target can re-roll at the end of their turn in combat. On a success, the target is immune to this effect for the next 30 minutes. 

Inflict Wounds. Melee Attack. Make a melee spell attack against a creature you can reach. On a hit, the target takes (3d10) Necrotic damage.

False Life. Bolstering yourself with a necromantic facsimile of life, you gain (1d4 + 4) temporary hit points for the duration.

2nd level (2 slots): Inflict Wounds. Melee Attack. Make a melee spell attack against a creature you can reach. On a hit, the target takes (4d10) Necrotic damage.

False Life. Bolstering yourself with a necromantic facsimile of life, you gain (1d4 + 9) temporary hit points for the duration.

Blindness/Deafness. You can blind or deafen a foe. Choose one creature that you can see within range to make a Constitution saving throw. If it fails, the target is either blinded or deafened (your choice) for the 1 minute. At the end of each of its turns, the target can make a Constitution saving throw. On a success, the spell ends.

Aura of Death. You invoke both death and life upon a 10-foot-radius sphere centered on a point within range. Each creature of your choice in that area must make a Constitution saving throw, taking 2d6 necrotic damage on a failed save, or half as much damage on a successful one. Nonmagical vegetation in that area withers.

In addition, one creature of your choice in that area can spend and roll one of its unspent Hit Dice and regain a number of hit points equal to the roll plus your spellcasting ability modifier.

Multiattack. The Wendigo makes two or three melee or ranged attacks: One Icy Claw Attack and one Bite Attack. On a successful Bite attack, the Wendigo can add a third attack as a Bonus Action, casting Hunger of the Damned, Hunger, or using the Pounce ability. If the Wendigo uses a Ranged Attack instead, it can attack twice with Bone Shard.

Icy Claw. Unarmed Attack: +9 to hit, reach 10 ft., one target. Hit: (4d6 + 5) slashing damage and (1d6 +5) cold damage. 

Bite Attack. Unarmed Attack: +9 to hit, reach 10 ft., one target. Hit: (2d8 + 5) Piercing damage and (1d6 +5) Necrotic damage. 

Bone Shard. Ranged Attack: +7 to hit, range 30/60 ft., two targets. Hit: (1d6 + 4) piercing damage and (1d4 + 5) Necrotic Damage. The Wendigo's form twists and cracks, revealing broken shards of bone. The bone shoots out from its place on the Wendigo's body at high speed directly at a creature within range. 

Bonus Action: Consume. At the end of its turn, as a Bonus Action, the Wendigo can supernaturally consume the rations of any creature within Melee range, gaining back 1d4 + 3 HP per day of rations available.

Bonus Action: Mask of the Wild. At the end of its turn, as a Bonus Action, The Wendigo can attempt to hide even if it only lightly obscured by foliage, heavy rain, falling snow, mist, or other natural phenomena 

Shower of Splinters. After being hit by a melee attack, the Wendigo, once per day, can use its reaction to send out a shower of antler and bone splinters in a 30 foot radius. All creatures within range must make a Dexterity saving throw (DC 18) or take (1d4 + 4) piercing damage and (1d4 + 4) Necrotic damage, embedding splinters of putrid bone into the skin. At the end of each turn, the creature must make a Constitution saving throw (DC 16) to remove the splinters or take an additional (1d4 + 4) Necrotic damage until the splinters are removed.

Retribution of the Starved. After being hit by a successful spell attack, once per day the Wendigo can respond with a wave of Necrotic energy directed toward the spellcaster. The target must make a Constitution saving throw (DC 16) or be struck with a deep, wasting hunger, taking (1d6 +4) Necrotic damage at the end of each turn until a successful save. 

The Wendigo invokes its Aura of Fear, targeting a specific creature that it can see.

Legendary Dread (1 Action). Three times per day, as a Legendary Action, the Wendigo targets a creature that it can see. Its eyes flicker momentarily red, and for a flash the creature sees a vision of the Wendigo ripping their body open and feeding on them while they are still alive. The creature must make a Wisdom saving throw (DC 15) or become Frightened for 1 minute. Previous saves against being Frightened do not protect a creature from the Wendigo's Legendary Dread.  The creature can re-roll the save at the end of each turn, ending the effect on a success.

Legendary Resistance (1 Reaction). Three times per day, if the Wendigo fails a Saving Throw, it can choose to succeed instead. 

When the Wendigo falls below half its HP, its bones become even more broken and twisted, jutting out from its corpse and through its shrink-wrapped fur at odd angles, making melee attacks more dangerous. 

Savaged Remains (1 Reaction). When the Wendigo falls below half its HP, as a Reaction, its bones become even more broken and twisted, jutting out from its corpse and through its shrink-wrapped fur at odd angles, creating a pincushion of piercing bone shards around its body. The Wendigo is now immune to being grappled by a creature of any size, and any attempts to grapple it automatically fail and deal (2d8 + 5) piercing damage. Melee or unarmed attacks against the Wendigo become treacherous. On a failed melee attack, the attacker must roll a Dexterity saving throw (DC 18), taking 1d4 +5 piercing damage on a failure. On an unarmed strike, this damage is doubled.