Cultist CR 12 (Paladin)

Spellcasting. The blackguard is a 10th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 16, +8 to hit with spell attacks). It has the following paladin spells prepared:

1st level (4 slots): command, protection from evil and good, thunderous smite

2nd level (3 slots): branding smite, crown of madness

3rd level (2 slots): blinding smite, bestow curse

4th level (1 slot): blight

Multiattack. The blackguard makes three attacks with its glaive or its shortbow.

Longsword. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 11 (2d8 + 7) slashing damage +1d8 necrotic damage 

Shortbow. Ranged Weapon Attack: +8 to hit, range 80/320 ft., one target. Hit: 5 (1d6 + 2) piercing damage.

Dreadful Aspect (Recharges after a Short or Long Rest). The blackguard exudes magical menace. Each enemy within 30 feet of the blackguard must succeed on a DC 16 Wisdom saving throw or be frightened for 1 minute. If a frightened target ends its turn more than 30 feet away from the blackguard, the target can repeat the saving throw, ending the effect on itself on a success.

Aura of Hate: the paladin, as well any fiends and undead within 10 feet of the paladin, gains a bonus to melee weapon damage rolls equal to the paladin’s Charisma modifier (minimum of +1). A creature can benefit from this feature from only one paladin at a time.