Actions

Multiattack. Fraz-Urb'luu makes four attacks using Claw or Trickter's Touch or a combination of the two. He can replace one of the attacks with Phantasmal Terror or Scam Sense.

Claw. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 9) force damage.

Phantasmal Terror. Fraz-Urb'luu targets one creature he can see within 120 feet of him. The target must succeed on a DC 23 Wisdom saving throw, or it takes 16 (3d10) psychic damage and is frightened of Fraz-Urb'luu until the end of its next turn.

Possession. Fraz-Urb'luu attempts to possess a creature or object within 30 feet of himself, though he does not need line of sight to it. The target must succeed on a DC 23 Charisma saving throw or be possessed by the Fraz-Urb'luu; his animus then disappears, and the target is incapacitated and loses control of its physical form. Fraz-Urb'luu controls the body but doesn't deprive the target of any awareness. Fraz-Urb'luu can't be targeted by any attack, spell, or other effect. Fraz-Urb'luu uses the possessed target's statistics, but doesn't gain access to the target's knowledge, class features, or proficiencies. He retains his alignment, Intelligence, Wisdom, Charisma, and immunity to being charmed and frightened.
The possession lasts until the vessel drops to 0 hit points, Fraz-Urb'luu ends it as a bonus action, or Fraz-Urb'luu is forced out by an effect like the dispel evil and good spell. When the possession ends, Fraz-Urb'luu reappears in an unoccupied space within 5 feet of the vessel. The target is immune to Fraz-Urbluu's Possession for 24 hours after succeeding on the saving throw or after the possession ends. Fraz-Urb'luu can possess the Argent Prince as a bonus action, the Argent Prince automatically fails its saving throw against possession, and the Argent Prince never gains immunity to this possession.

Scam Sense. Fraz-Urb'luu observes a creature and magically knows its current emotional state. If the target fails a DC 23 Charisma saving throw, he also knows the creature's alignment and creature type.

Trickster's Touch. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 18 (2d8 + 9) necrotic or radiant damage. The target must roll on the Wild Magic Surge Table (PHB'14, p 103), treating itself as the referent. If the effect causes is a spell, the target casts the spell even if it is not normally capable of doing so, using Charisma as the ability score. If that effect is a spell that would normally requires concentration, it doesn't require concentration; the spell lasts for its full duration.

Bonus Actions

Altered Aegis. Fraz-Urb'luu changes the color of the Argent Prince to match the color and texture of its surroundings, gaining advantage on Dexterity (Stealth) checks it makes to hide in those surroundings.

Extract Truth. Fraz-Urb'luu targets one creature it can see within 30 feet of it. The target must contest its Charisma (Deception) check against the Fraz-Urb'luu's Wisdom (Insight) check. If Fraz-Urb'luu wins, he magically discovers a hidden secret or fact about the target. This information need not be one known to the target. The target automatically wins if it is immune the charmed condition.

Legendary Actions

Legendary Action Uses: 3. Immediately after another creature's turn, Fraz-Urb'luu can expend a use to take one of the following actions. Fraz-Urb'luu regains all expended uses at the start of each of his turns.

I'm Not Hitting You, You're Hitting You. Fraz-Urb'luu forces a creature he can see within 30 feet of him to make a DC 23 Wisdom saving throw. On a failure, the creature immediately uses its reaction to target itself with a melee weapon attack or an unarmed strike if it is not holding a melee weapon.

Babble. Fraz-Urb'luu utters a fragment of beguiling speech in a language of his choice. Each creature within 60 ft of Fraz-Urb'luu that can hear him must make a Wisdom (Insight) check contested by Fraz-Urb'luu's Charisma (Deception). If Fraz-Urb'luu wins a contest, that target can only speak in the language used by Fraz-Urb'luu until the end of its next turn. This does not confer any ability to understand the language if it is not one that a target understands. A target automatically wins a contest if it is immune the charmed condition.

Terror (Costs 2 Actions). Fraz-Urb'luu uses Phantasmal Terror.

Spell (Costs 2 Actions). Fraz-Urb'luu casts a spell with a casting time of one action, one bonus action, or one reaction.

Lair Actions

On initiative count 20 (losing initiative ties), Fraz-Urb'luu can take one of the following lair actions when in his lair; he can't take the same lair action two rounds in a row:

Conjure Walls and Doors. Fraz-Urb'luu causes up to five doors within the lair to become walls and an equal number of doors to appear on walls where there previously were none.

Psychic Anguish. Fraz-Urb'luu creates a wave of anguish. Each creature of his choice that he can see within the lair must succeed on a DC 23 Wisdom saving throw or take 33 (6d10) psychic damage.

Simulacrum. Fraz-Urb'luu chooses one Humanoid within the lair and instantly creates a simulacrum of that creature (as if created with the simulacrum spell). This simulacrum obeys Fraz-Urb'luu's commands and is destroyed on the next initiative count 20.

Regional Effects

The region containing Fraz-Urb'luu's lair is warped by his magic, creating one or more of the following effects:

Beguiling Realm. Within 6 miles of the lair, all Charisma (Persuasion) and Wisdom (Insight) checks have disadvantage, and all Charisma (Deception) and Charisma (Performance) checks have advantage.

Nostalgic Pangs. Sapient creatures within 1 mile of the lair frequently see hallucinations of long-dead friends and comrades that vanish after only a brief glimpse.

Twisted Paths. Roads and paths within 6 miles of the lair twist and turn back on themselves, making navigation in the area exceedingly difficult.