Dark Power. Attacks the wraith makes against any target within an area of dim light or darkness critically hit on a roll of 19 or 20.

Incorporeal Movement. The wraith can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Smother Light. The radius of all light sources within 90 feet of the wraith are halved. Light sources within 5 feet of the wraith are extinguished if they were not created by a spell of 4th-level or higher.

Sunlight Sensitivity. While in sunlight, the wraith has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

Life Drain. Melee Spell Attack: +6 to hit, reach 5 ft., one creature. Hit: 21 (4d8 + 3) necrotic damage. The target must succeed on a DC 14 Constitution saving throw or it gains a level of exhaustion.

Shadow Grasp. Melee Spell Attack: +5 to hit, reach 60 ft., one creature in dim light or darkness. Hit: 9 (2d6 + 2) necrotic damage, and the target's Strength score is reduced by 2 (1d4). The target dies if this reduces its Strength score to 0. Otherwise, the reduction lasts until the target finishes a short or long rest. If this attack is a critical hit, a shadow under the wraith's control appears in a space within 5 feet of the target. 

Fade Away. After taking damage other than radiant while in dim light or darkness, the wraith can become invisible and fly up to 30 feet, becoming visible again at the start of its next turn or when it is in an area of bright light.

VILLAIN ACTIONS: 

1. Vivus Maledictum. The wraith curses a target creature it can see within 60 feet. The target creature must succeed a DC 14 Constitution saving throw or it takes 9 (2d8) necrotic damage at the end of each turn and must succeed a DC 14 Constitution saving throw each time or its maximum hit points are reduced by the total value of the dice until its next long rest. This effect lasts until the target receives magical healing or is the target of a remove curse spell. The creature that removes this effect from another creature must succeed a saving throw against the effect or become affected by it, the saving throw is made with disadvantage if it is ended using magical healing. A creature cannot remove this effect from itself.

2. Snuff them Out. All creatures within 90 feet of the wraith must make a DC 14 Strength saving throw taking 7 (2d6) force damage on a failure or half as much on a success. All light sources within the area are extinguished.

3. Soul Siphon. All creatures within 60 feet of the wraith must make a DC 14 Constitution saving throw or take 13 (3d8) necrotic damage and gain a level of exhaustion. A creature that succeeds this save takes half as much damage and no exhaustion. The wraith can choose to regain hit points equal to half of the damage dealt or give an allied undead within 90 feet temporary hit points equal to half of the damage dealt. Constructs and undead take no damage from this ability.