Nightwalker

(From Mordenkainen's Tome of Foes - 2018):

The Negative Plane is a place of darkness and death, anathema to all living things. Yet there are those who would tap into its fell power, to use its energy for sinister ends. Most often, when such individuals approach the midnight realm, they find they are unequal to the task. Those not destroyed outright are sometimes drawn inside the plane and replaced by nightwalkers, terrifying undead creatures that devour all life they encounter.

Mighty Spawn. One can reach the Negative Plane from the Shadowfell, much in the same way that it is possible to step from the Material Plane into the Shadowfell in a place where the barrier between the planes is thin.

Stepping into the Negative Plane is tantamount to suicide, since the plane sucks the life and soul from such audacious creatures and annihilates them at once. Those few who survive the effort do so by sheer luck or by harnessing some rare form of magic that protects them against the hostile atmosphere. They soon discover, however, that they can’t leave as easily as they arrived. For each creature that enters the plane, a nightwalker is released to take its place. In order for a trapped creature to escape, the released nightwalker must be lured back to the Negative Plane by offerings of life for it to devour. If the nightwalker is destroyed, the trapped creature has no hope of escape.

Beings of Anti-Life. One can discern the nature of creatures trapped in the Negative Plane from the sites that nightwalkers frequent. Generally, a nightwalker on the Material Plane is attracted to elements of the world associated with the creature responsible for its creation. Such interest doesn’t indicate a willingness to engage with the world; nightwalkers exist to make life extinct and never to serve living things.

Undead Nature. A nightwalker doesn’t require air, food, drink, or sleep.

(From v3.5 Monster Manual I - 2003):

The creature looks like a humanoid giant, taller than a house and composed of pure darkness. It wears no clothing and has smooth, hairless skin and a genderless body. 

Nightwalkers are human-shaped horrors that haunt the darkness. A nightwalker is about 20 feet tall and weighs about 12,000 pounds.

Nightwalkers lurk in dark areas where they can almost always surprise the unwary. 

A nightwalker’s natural weapons are treated as magic weapons for the purpose of overcoming damage reduction. 

Crush Item (Su): A nightwalker can destroy any weapon or item of Large size or smaller (even magic ones, but not artifacts) by picking it up and crushing it between its hands. The nightwalker must make a successful disarm attempt to grab an item held by an opponent. The item is entitled to a DC 34 Fortitude save to resist destruction. The save DC is Strength-based. 

Evil Gaze (Su): Fear, 30 feet. A creature that meets the nightwalker’s gaze must succeed on a DC 24 Will save or be paralyzed with fear for 1d8 rounds. Whether or not the save is successful, that creature cannot be affected again by the same nightshade’s gaze for 24 hours. This is a mind-affecting fear effect. The save DC is Charisma-based. 

Spell-Like Abilities: At will—contagion (DC 18), deeper darkness, detect magic, greater dispel magic, haste, see invisibility, and unholy blight (DC 18); 3/day—confusion (DC 18), hold monster (DC 19), invisibility; 1/day—cone of cold (DC 19), finger of death (DC 21), plane shift (DC 21). Caster level 21st. The save DCs are Charisma-based. 

Summon Undead (Su): A nightwalker can summon undead creatures once per night: 7–12 shadows, 2–5 greater shadows, or 1–2 dread wraiths. The undead arrive in 1d10 rounds and serve for 1 hour or until released. 

Skills: *When hiding in a dark area, a nightwalker gains a +8 racial bonus on Hide checks.