Devil's Sight.

Magical darkness doesn't impede the deathlock's darkvision.

Turn Resistance.

The deathlock has advantage on saving throws against any effect that turns Undead.

Unusual Nature.

The deathlock doesn't require air, food, drink, or sleep.

Actions

Multiattack.

The deathlock makes two Deathly Claw or Grave Bolt attacks.

Deathly Claw.

Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (3d6 + 3 necrotic damage).

Grave Bolt.

Ranged Spell Attack: +6 to hit, range 120 ft., one target. Hit: 13 (3d8) necrotic damage. If the target is Large or smaller, it must succeed on a DC 16 Strength saving throw or become restrained as shadowy tendrils wrap around it for 1 minute. A restrained target can use its action to repeat the saving throw, ending the effect on itself on a success.

Spellcasting.

The deathlock casts one of the following spells, using Charisma as the spellcasting ability (spell save DC 14):

At will: detect magic, disguise self, mage armor, minor illusion
1/day each: darkness, dimension door, dispel magic, fly, invisibility

Environment: Urban

Deathlock Mastermind