Cult Fanatic Lord

Dark Devotion: The Fanatic has advantage on saving throws against being charmed or frightened.

Corrupted Light: Whenever the Fanatic would deal radiant damage, it instead deals necrotic damage.

Spellcasting: The Fanatic is a 5th-level spellcaster. Its spellcasting ability is Wisdom (spell save DC 12, +4 to hit with spell attacks). The Fanatic has the following cleric spells prepared:
Cantrips (at will): guidance, sacred flame, thaumaturgy
1st level (4 slots): command, inflict wounds, shield of faith
2nd level (3 slots): hold person, spiritual weapon
3rd level (2 slots): bestow curse, spirit guardians

Multiattack. The Fanatic makes two attacks: one with its scimitar and one with its dagger or a cantrip.

Scimitar. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 2) slashing damage.

Dagger. Melee or Ranged Weapon Attack: +4 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 4 (1d4 + 2) piercing damage.

Fanatical Command (One Time Use): 
The Fanatic targets one creature it can see within 30 ft. The target must succeed on a DC 13 Wisdom saving throw or be charmed by the Fanatic for 1 minute or until it takes damage. A charmed target must use its action on its next turn to attack a creature of the Fanatic’s choice other than itself.

Fanatical Zeal (Recharge 5-6)
As a bonus action when the Fanatic is reduced to half its hit points or fewer for the first time, it enters a zealous phase. During this phase:

• Its speed increases to 40 ft.
• It regains 11 (2d6 + 4) hit points.
• Its spiritual weapon and spirit guardians deal an extra 1d8 necrotic damage on a hit or in the area.

At the end of this phase, it can repeat the effect if it recharges.

Aura of Fear (1/round):  Each creature within 10 ft. must succeed on a DC 13 Wisdom saving throw or be frightened until the end of its next turn. On a success, the creature is immune to this aura for 24 hours.

Blessing of Tyranny
When the Fanatic is reduced to 15 hit points or fewer, a malevolent deity grants it this blessing as a reaction (lasts until the Fanatic is defeated or 3 rounds pass). During this phase:

• The Fanatic gains 10 temporary hit points.
• Its melee attacks deal an extra 2 necrotic damage.
• Gain the bonus action Aura of Fear