Armor Class 17 (natural armor)
Hit Points 170 (20d10 + 60)
Speed 40 ft., fly 20 ft.
Saving Throws Dex +10, Con +8, Wis +9, Cha +11
Skills Arcana +10, Deception +11, Insight +9, Perception +9, Persuasion +11
Damage Immunities bludgeoning, fire, piercing, poison, slashing
Condition Immunities charmed, frightened, paralyzed, petrified, poisoned, prone, restrained, stunned
Senses blindsight 10 ft., darkvision 120 ft., passive Perception 19
Languages Common, Infernal, Primordial, telepathy 120 ft.
Challenge 15 (13,000 XP)
Collective Mind. Ia'Affrat's individual Fiends are connected via a hive mind. He can telepathically communicate with any of his individual Fiends within 50 miles of him, and he can't be surprised. If he is reduced to half his hp or lower, his Intelligence score is reduced to 10, he immediately changes into his shapeless form, and he can't take on a Humanoid form again until he regains hp to be above half his hp or he finishes a long rest.
Devil's Sight. Magical darkness doesn't impede Ia'Affrat's darkvision.
Grasping Limbs (Humanoid Form Only). Ia'Affrat can wield weapons and hold, grasp, push, pull, or interact with objects that might otherwise require a more Humanoid form to accomplish.
Legendary Resistance (3/Day). If Ia'Affrat fails a saving throw, he can choose to succeed instead.
Magic Resistance. Ia'Affrat has advantage on saving throws against spells and other magical effects.
Smoke Shroud. Ia'Affrat emits a cloud of dark smoke within 5 feet of himself. The area is lightly obscured to all except Ia'Affrat, and each non-devil creature that starts its turn in the smoke must succeed on a DC 18 Constitution saving throw or be blinded until the end of its turn. At the start of each of his turns, Ia'Affrat chooses whether this shroud is active.
Swarm (Shapeless Form Only). Ia'Affrat can occupy another creature's space and vice versa and can move through any opening large enough for a Tiny insect, but he can't grapple or be grappled.
Multiattack. Ia'Affrat makes three Bite or Burning Claw attacks, or he makes four Flaming Insect Bolt attacks.
Bite (Shapeless Form Only). Melee Weapon Attack: +10 to hit, reach 0 ft., one target in the swarm's space. Hit: 21 (6d6) piercing damage plus 14 (4d6) poison damage, or 10 (3d6) piercing damage plus 7 (2d6) poison damage if Ia'Affrat has half of its hp or fewer. If the target is a creature, it must succeed on a DC 18 Constitution saving throw or be poisoned until the end of its next turn.
Burning Claw (Humanoid Form Only). Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 23 (4d8 + 5) slashing damage plus 10 (3d6) fire damage.
Flaming Insect Bolt. Ranged Spell Attack: +11 to hit, range 120 ft., one target. Hit: 16 (3d6 + 6) fire damage plus 10 (3d6) poison damage.
Inhabit (Shapeless Form Only). Ia'Affrat crawls into the body of a Humanoid, or a Humanoid corpse that has been dead no more than 7 days, that he can see within 5 feet of him. If the target is unwilling, the target must succeed on a DC 18 Constitution saving throw or the target loses control of its body, and Ia'Affrat takes control of the body. Ia'Affrat controls the body but doesn't deprive the target of awareness. Ia'Affrat can't be targeted by any attack, spell, or other effect, and he retains his alignment, his Intelligence, Wisdom, and Charisma scores, his Hurl Flame action and Teleport and Consume Host legendary actions, and his condition immunities. He otherwise uses the target's statistics, but doesn't gain access to the target's knowledge, class features, or proficiencies. If the target was a Humanoid corpse, he uses the statistics it had before it died.
Ia’Affrat 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. Ia’Affrat regains spent legendary actions at the start of his turn.
Teleport. Ia'Affrat teleports, along with any equipment he is wearing or carrying, up to 120 feet to an unoccupied space he can see.
Vermin Breath (Costs 2 Actions; Humanoid Form Only). Ia'Affrat exhales 1d4 swarms of insects in spaces he can see within 30 feet. The swarms take their turns immediately after Ia'Affrat, and they are allies of Ia'Affrat, obeying his telepathic commands. They remain for 1 minute, until Ia'Affrat dies, or until Ia'Affrat dismisses them as a bonus action. Ia'Affrat can have no more than five swarms of insects under his control at a time.
Consume Host (Costs 3 Actions; Shapeless Form Only). While inhabiting a Humanoid, Ia'Affrat consumes the host from the inside. The host takes 18 (4d8) necrotic damage, and Ia'Affrat regains hp equal to that amount.