Inviolate Presence.

The veiled presence can't be targeted by divination magic or by features that would read its mind or determine its creature type.

Legendary Resistance (3/Day).

If the veiled presence fails a saving throw, it can choose to succeed instead.

Actions

Multiattack.

The veiled presence makes two Blade of Judgment attacks and can use Revelation.

Blade of Judgment.

Melee or Ranged Weapon Attack: +14 to hit, reach 5 ft. or range 60 ft., one target. Hit: 10 (1d6 + 7) piercing damage plus 27 (6d8) radiant damage. If the target is a creature, it must succeed on a DC 22 Charisma saving throw, or on its next turn, it can either move or take an action, but not both.

Revelation.

The veiled presence reveals a glimpse of its otherworldly nature to a creature it can see within 30 feet of itself. The target must succeed on a DC 22 Wisdom saving throw or have the paralyzed condition until the end of its next turn, after which the target is immune to this Revelation for 24 hours.

Reactions

Uncanny Dodge.

When an attacker the veiled presence can see hits the veiled presence with an attack, the veiled presence halves the attack's damage against it.

Legendary Actions

The veiled presence 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 veiled presence regains spent legendary actions at the start of its turn.

Flash Step. The veiled presence magically teleports, along with any equipment it is wearing or carrying, up to 40 feet to an unoccupied space that it can see.
Stab (Costs 2 Actions). The veiled presence makes one Blade of Judgment attack.
Searing Radiance (Costs 3 Actions). The veiled presence magically emanates dazzling light in a 10-foot-radius sphere centered on itself until the end of its next turn, during which time attack rolls against it have disadvantage and it has advantage on attack rolls. The sphere moves with the veiled presence. When another creature starts its turn in the light or enters the light for the first time on its turn, that creature must make a DC 22 Constitution saving throw, taking 18 (4d8) radiant damage on a failed save, or half as much damage on a successful one.

Lair Actions

On initiative count 20 (losing initiative ties) while in its lair, the villain can take one of the following lair actions; the villain can't take the same lair action two rounds in a row:

Distraction. A shrill sound fills the lair. Creatures that can hear it must succeed on a DC 15 Constitution saving throw or lose concentration.
Snares. Hidden snares target up to three creatures the villain can see in the lair. Each creature must succeed on a DC 15 Strength saving throw or have the grappled condition (escape DC 15) and the restrained condition until it escapes or the snare holding it is destroyed. Each snare has AC 11, 10 hit points, and immunity to poison and psychic damage.
Traps. Traps target up to two creatures the villain can see in the lair. Each target must succeed on a DC 15 Dexterity saving throw or be struck by a trap. The villain rolls a number of d6s equal to its proficiency bonus, and struck targets take damage equal to the total. The damage is bludgeoning, piercing, slashing, fire, or poison, chosen by the villain when the villain uses this action.

Regional Effects

The region containing a villain's lair is warped by their presence, creating one or more of the following effects:

Corruption Abounds. While within 3 miles of the lair, creatures that aren't members of the villain's organization have disadvantage on ability checks that rely on the Insight, Perception, and Persuasion skills.
Potent Toxins. When members of the villain's organization deal poison damage while within 3 miles of the lair, they ignore the target's resistance to poison damage.

If the villain dies, these effects fade over the course of 1d10 days.

Veiled Presence