Cult Prophet

Key of Prophecy. The Cult Prophet can always act in a surprise round, but if he fails to notice a foe, he is still considered surprised until he takes an action. He receives a +8 bonus on initiative checks.

Innate Spellcasting. The Cult Prophet innate spellcasting ability is Wisdom (spell save DC 17). He can innately cast the following spells, requiring no material components:

3/day each: detect thoughts, dimension door, haste, slow

2/day each: suggestion, teleport

1/day each: scrying

Spellcasting: The Cult Prophet is a 19th-level spellcaster. His spellcasting ability is Wisdom (spell save DC 20, +12 to hit with spell attacks). The Cult Prophet has the following cleric spells prepared:

Cantrips (at will): guidance, light, sacred flame, spare the dying, thaumaturgy
1st level (4 slots): cure wounds, inflict wounds, guiding bolt

2nd level (3 slots): silence, spiritual weapon, hold person

3rd level (3 slots): dispel magic, mass healing word, spirit guardians

4th level (3 slots): banishment, Freedom of Movement, guardian of faith

5th level (3 slots): flame strike, summon celestial, Mass Cure Wounds

6th level (2 slot): harm, Blade Barrier

7th level (1 slot): Fire Storm

8th level (1 slot): Holy Aura

9th level (1 slot) Mass Heal

Legendary Resistance (3/Day). If the Cult Prophet fails a saving throw, it can choose to succeed instead.

Multiattack. The Cult Prophet can either make two melee attacks and cast a cantrip or use a spell and a cantrip.

Mace. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 5 (1d6)+3 bludgeoning damage. 

Esoteric Vengence. As a reaction when struck by a melee attack, the Cult Prophet can expend a spell slot to do 21 (6d6) necrotic damage to the attacker. If the Cult Prophet expends a spell slot of 2nd level or higher, the damage increases by 1d6 for each level above 1st.

The cult prophet 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 cult prophet regains spent legendary actions at the start of its turn.

Mace Attack (Costs 1 Action). The cult prophet makes a mace attack.

Darkness (Costs 2 Actions). The cult prophet is enshrouded by a 20ft sphere of magical darkness until the end of their next turn

Cast a Spell (Costs 3 Actions). The cult prophet cases a spell from its list of prepared spells, using a spell slot as normal