Afarit, Lord of Beasts, God of the Flesh, the Great Devourer

• Shapechanger. Afarit can use his action to polymorph into any Beast or Monstrosity up to CR 20, or back into his true form (a tall man with a fiery goat skull). His statistics, other than his size, are the same in each form. Any equipment he is wearing or carrying isn't transformed. He reverts to his true form if he dies.
• Innate Spellcasting. Afarit’s innate spellcasting ability is Charisma (spell save DC 22, +14 to hit with spell attacks). He can innately cast the following spells, requiring no material components:
  • Constant: Detect Magic, Speak with Animals
  • At will: Alter Self, Command, Fire Bolt (17th level), Hellish Rebuke
  • 3/day each: Dominate Beast, Fire Shield, Wall of Fire
  • 1/day each: Animal Shapes, Fire Storm, Power Word Stun
• Lord of the Flesh. Afarit has total mastery over organic matter. He is immune to any effect that would alter his form against his will. Additionally, whenever Afarit deals bludgeoning, piercing, or slashing damage, he regains hit points equal to half the damage dealt.
• Legendary Resistance (4/Day). If Afarit fails a saving throw, he can choose to succeed instead.
• Magic Resistance. Afarit has advantage on saving throws against spells and other magical effects.
• Master of Flesh. Afarit's attacks bypass all damage resistances and immunities of living creatures. He deals double damage to objects and structures.
• Aura of the Ravenous Dread. Mortals are nothing but prey to the Lord of Hungers. Any creature of Afarit’s choice that starts its turn within 60 feet of him must succeed on a DC 23 Wisdom saving throw. On a failure, the creature is Frightened until the start of its next turn.
  While Frightened by this aura, the creature suffers from an overwhelming, gnawing hunger; it cannot gain temporary hit points, and any healing it receives from spells or items is halved as its own biology rapidly consumes itself.

Multiattack. Afarit makes three attacks: one with his Fiery Horns and two with his Flesh-Rending Claws.

Fiery Horns (Beast/Humanoid Form Only). Melee Weapon Attack: +17 to hit, reach 15 ft., one target.

Hit: 27 (4d8 + 9) piercing damage plus 18 (4d8) fire damage. If the target is a creature, it must succeed on a DC 25 Strength saving throw or be knocked prone.

Flesh-Rending Claws. Melee Weapon Attack: +17 to hit, reach 20 ft., one target.

Hit: 23 (4d6 + 9) slashing damage. The target must succeed on a DC 24 Constitution saving throw or its hit point maximum is reduced by an amount equal to the slashing damage taken. 

Lord of the Hunt (Recharge 5–6). Afarit unleashes a primal roar. Every creature of Afarit's choice within 120 feet must make a DC 23 Wisdom saving throw. On a failure, a creature takes 45 (10d8) psychic damage and is Frightened for 1 minute. On a success, it takes half damage and isn't Frightened.

• Typhoon & Flood: A massive deluge sweeps a 60-foot radius centered on a point Afarit can see within 120 feet. Each creature in that area must make a DC 24 Strength saving throw. On a failure, a creature takes 44 (8d10) bludgeoning damage, is knocked prone, and is pushed 30 feet away from the center. On a success, it takes half damage and isn't prone or pushed.
• Fire Storm: Rain of fire falls in a 40-foot-high, 30-foot-radius cylinder centered on a point Afarit can see within 150 feet. Each creature in the area must make a DC 24 Dexterity saving throw, taking 52 (15d6) fire damage on a failed save, or half as much on a successful one.
• Earth-Cracking Quake: Afarit strikes the ground. The earth fractures in a 90-foot cone. Each creature on the ground in that area must make a DC 24 Dexterity saving throw. On a failure, a creature takes 45 (10d8) bludgeoning damage and falls into a fissure, becoming Restrained (escape DC 24). The ground in the cone becomes difficult terrain.

• Shift Form. Afarit uses his Shapechanger trait to transform into a different physical shape or revert to his humanoid form.
• Ignite the Blood. Afarit targets one creature within 60 feet that has taken damage from his Flesh-Rending Claws this turn. The target's wounds erupt in white-hot flames, dealing 14 (4d6) fire damage.
• Flesh Over Mind. Afarit asserts absolute control over his own biology. He ends one condition currently affecting him: Blinded, Deafened, or Stunned.

• Flesh Armor. When a creature hits Afarit with a melee weapon attack, his flesh hardens like iron. He gains a +5 bonus to his AC against that attack, potentially causing it to miss. If the attack still hits, the attacker takes 10 (3d6) fire damage from the heat radiating from his skin.
• Reactive Mutation. When Afarit takes acid, cold, lightning, or thunder damage, his body instantly mutates to adapt. He gains resistance to that damage type until the end of his next turn.
• Spiteful Rebuke. When a creature within 60 feet forces Afarit to make a saving throw, he casts Hellish Rebuke (5th level) at that creature as a reaction, using his innate spellcasting.

• Afarit 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. Afarit regains spent legendary actions at the start of his turn.
• 
  Move. Afarit moves up to his speed without provoking opportunity attacks.
• Claw. Afarit makes one Flesh-Rending Claws attack.
• Channelling Wildfire (Costs 2 Actions). Afarit casts Fireball or Wall of Fire from his innate spell list.
• Arrière-Ban (Costs 3 Actions). Afarit exerts his divine right as the Lord of Flesh over one of his ancient signets (such as the Red Ring). He targets one creature he can see within 120 feet that is currently carrying or wearing one of these signets. The target must succeed on a DC 24 Constitution saving throw or its physical form violently mutates, transforming into a weaker, flesh-warped version of the boss monster associated with that signet (e.g., a lesser Dullahan).While transformed, the target's game statistics are replaced by the monster's stat block, it is under Afarit's telepathic control, and it acts immediately after Afarit in the initiative order. The transformation lasts for 1 minute, until Afarit dies, or until the transformed creature drops to 0 hit points, at which point the target reverts to its normal form and any excess damage carries over.

• Flames of Creation (Costs 2 Actions). Afarit emits a wave of biological fire. Each creature within 30 feet must make a DC 24 Constitution saving throw. On a failure, a creature takes 36 (8d8) fire damage and its flesh begins to mutate, giving it disadvantage on all attack rolls and ability checks until the end of its next turn. On a success, it takes half damage and suffers no mutation.
• Command the Cellular Structure (Costs 3 Actions). Afarit targets one creature he can see within 60 feet. The target must succeed on a DC 23 Constitution saving throw or immediately expend half of its remaining Hit Dice, taking necrotic damage equal to the total rolled.
• The Grand Arrière-Ban (Costs 3 Actions). Afarit activates his Arrière-Ban feature, but the target makes the saving throw with disadvantage. Furthermore, if a player has already reverted from a transformation earlier in the fight, the signet rings violently heat up, dealing 28 (8d6) fire damage to the bearer automatically, bypassing fire resistance as Afarit reasserts his dominion over "all that is physical."