Unhallowed Apostle

Deathsong Aura. All living creatures within 30 feet of the apostle take 9 (2d8) necrotic damage at the start of each of their turns. Undead within that aura gain a +2 bonus to their damage rolls and saving throws. Additionally, allied undead within the aura gain advantage on effects that turn undead. 

The Deathsong. The Unhallowed Apostle can use its action to sing the Deathsong, a haunting melody imbued with the essence of Nihil. All creatures within a 60-foot radius that can hear the song must make a DC 20 Wisdom saving throw or be frightened for 1 minute. While frightened by the Deathsong, creatures have disadvantage on saving throws against necrotic damage. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. 

When an undead creature the apostle controls deals damage, it can mark the target with a fragment of the Deathsong. Marked creatures have disadvantage on death saving throws and cannot regain hit points for 1 minute unless they succeed on a DC 20 Wisdom saving throw.

Unusual Nature. The apostle doesn’t require air, food, drink, or sleep.

Void Empowerment. Any necrotic damage dealt by the apostle ignores resistance. The prophet adds a +7 to damage rolls made with necromancy spells. 

Reaper. When the apostle casts a necromancy cantrip or spell of 1st through 5th level that targets only one creature. The spell instead targets two within range and within 5 feet of each other. 

Lich Resilience. The apostle has advantage on saving throws against any effect that turns Undead. As well as spells and another magical effects. 

Legendary Resistance (3/day). Whenever the apostle fails a saving throw, it can use one of its legendary resistances to succeed instead. 

Multiattack. The apostle makes two Corrupted Staff or Necrotic Bolt attacks.

Corrupted Staff. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 13 (3d6 + 6) bludgeoning damage, plus 18 (4d8) necrotic damage. 

Necrotic Bolt. Ranged Spell Attack: +12 to hit, range 120 ft., one target. Hit: 27 (6d8) 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.

Death's Grasp (Recharge 5-6). The Unhallowed Apostle can use its action to reach out and grasp a target within 30 feet. The target must make a DC 20 Strength saving throw or be pulled up to 20 feet closer to the Apostle taking 33 (6d10) necrotic damage and is restrained. The Apostle regains hit points equal to the amount of necrotic damage dealt.

Spellcasting. The apostle casts one of the following spells, using Wisdom as the spellcasting ability (spell save DC 20, +12 to hit with spell attacks):

At will: Detect Magic, Chill Touch, Shield of Faith, Inflict Wounds

2/day each: Silence, Animate Dead, Dispel Magic, Circle of Death

1/day each: Cloudkill, Hallow, Harm, Finger of Death

Touch of Death (3/day). When the apostle hits with a melee attack, it deals and extra 45 necrotic damage. 

Nihil's Embrace (1/day). As an action, the Unhallowed Apostle can call upon Nihil’s power, surrounding a creature of its choice within 60 feet in a swirling vortex of necrotic energy. The target must make a DC 19 Constitution saving throw or take 33 (6d10) necrotic damage and be paralyzed for 1 minute. On a successful save, the creature takes half damage and is not paralyzed. The paralysis can be ended early by a greater restoration spell or similar magic.

Voidstep. As a bonus action, the apostle can teleport to an unoccupied space it can see within 30 feet. This movement does not provoke opportunity attacks, creatures within 5 feet of the starting and ending point of the apostle's teleportation takes 6 necrotic damage. 

Prophet's Blessing. When a creature within 60 feet dies, the apostle can use its reaction to raise it as a spectral servant for 1 hour. The servant acts as a specter under its control, obeying its verbal commands.

Void's Embrace. When the apostle takes damage, it can use its reaction to absorb part of it into the void. The apostle takes half damage, and the attacker takes the remaining damage as necrotic energy, which cannot be reduced or negated.

Nihil's Grace. The Unhallowed Apostle is a powerful servant of Nihil, the Dragon of the Void. The Apostle has resistance to radiant damage and can use its reaction to absorb the energy from a radiant damage attack, reducing the damage by half and healing for an amount equal to the damage reduced.

The apostle can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The apostle regains spent legendary actions at the start of its turn.

Necrotic Wave. The Unhallowed Apostle sends out a wave of necrotic energy in a 15-foot cone. Each creature in that area must make a DC 19 Constitution saving throw or take 10 (3d6) necrotic damage, or half as much on a successful save.

Cast a Spell (Costs 2 Actions). The Unhallowed Apostle casts a spell from its list of prepared spells.

Channel the Deathsong (Costs 3 Actions). The Unhallowed Apostle intensifies its Deathsong, causing all creatures that are already frightened by it to make a DC 20 Constitution saving throw or take 14 (4d6) necrotic damage at the start of their turn. Or half that damage on a successful save.