Creature Sense. Voalsh is aware of the presence of creatures within 5 miles of her that have an Intelligence score of 4 or higher. She knows the distance and direction to each creature, as well as each one’s Intelligence score, but can’t sense anything else about it. A creature protected by a mind blank spell, a nondetection spell, or similar magic can’t be perceived in this manner.

Legendary Resistance (4/Day). If Voalsh fails a saving throw, she can choose to succeed instead.

Magic Resistance. Voalsh has advantage on saving throws against spells and other magical effects.

Mental Infiltrator. Creature's that have a psychic link with Voalsh make any saving throws imposed by mind flayers with a -5 penalty.

Psionic Crusher. Voalsh adds her Intelligence modifier to any psychic damage she inflicts (included in attacks)

Siege Monster. Voalsh deals double damage to objects and structures.

Telepathic Eavesdropping. Voalsh can overhear any telepathic conversation within 5 miles of her. The creature that initiated the telepathic conversation makes a DC 21 Wisdom saving throw when telepathic contact is first established. If the save is successful, the creature is aware that something is eavesdropping. The nature of the eavesdropper isn’t revealed.

Telepathic Hub. Voalsh can use her telepathy to initiate and maintain telepathic conversations with up to ten creatures at a time. She can let those creatures telepathically hear each other while connected in this way.

Multiattack. Voalsh makes one Bite attack, two Claw attacks, and one Tentacle attack. She can replace two attacks to cast a spell or use her Tadpole Brine Breath (if available) or Unleash Void (if available).

Bite. Melee Weapon Attack: +16 to hit, reach 15 ft., one target. Hit: 19 (2d10 + 8) piercing damage plus 16 (2d10 + 5) psychic damage. If the target is an incapacitated Humanoid or Giant grappled by Voalsh, it takes an additional 55 (10d10) piercing damage. If this damage reduces the target to 0 hit points, Voalsh kills it by extracting and devouring its brain.

Claw. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 17 (3d6 + 8) slashing damage.

Tentacle. Melee Weapon Attack: +16 to hit, reach 15 ft., one creature. Hit: 29 (3d10 + 13) psychic damage. If the target is Huge or smaller, it has the grappled condition (escape DC 19) and must succeed on a DC 21 Intelligence saving throw or have the incapacitated condition until the grapple ends. Voalsh can have up to four targets grappled at a time.

Spellcasting (Psionics). The mind flayer casts one of the following spells, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 21):

At will: detect magic, detect thoughts, mage hand (the hand is invisible), Telekinesis, Gravity Fissure, Gravity Sinkhole, Wall of Force

3/day each: clairvoyance (as an action), dispel magic, modify memory, Raulothim's Psychic Lance, Reality Break

1/day: plane shift (self only), dominate monster, Ravenous Void

Tadpole Brine Breath (Recharge 5–6). Voalsh exhales brine in a 120-foot line that is 15 feet wide. Each creature in that area must make a DC 23 Constitution saving throw, taking 60 (10d10 + 5) psychic damage on a failed save, or half as much damage on a successful one. On a success or failure, if the creature isn’t a Construct or an Undead, it becomes infested with illithid tadpoles.

While infested, the creature takes 21 (3d10 + 5) psychic damage at the start of each of its turns. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself after it succeeds on three of these saves. If the creature is targeted by magic that ends a curse or restores 40 hit points or more, the tadpoles infesting the creature are killed instantly, ending the effect on the creature.

If a Humanoid is reduced to 0 hit points while infested, the creature is stable but remains unconscious for 6d12 hours. When the period of unconsciousness ends, the creature transforms into a mind flayer (see the Monster Manual) with all its hit points. Casting a wish spell on the unconscious creature rids it of the infestation and prevents it from turning into a mind flayer.

Unleash Void (Recharge 5–6). The mind flayer opens a rift into the Far Realm, centered on a point the mind flayer can see within 60 feet of itself, and a tentacle lashes across creatures near the rift. Each creature other than mind flayers within 30 feet of the rift must make a DC 21 Intelligence saving throw, after which the tentacle disappears and the rift closes. On a failed save, a creature takes 24 (6d8) cold damage from the rift plus 29 (6d8 + 5) psychic damage from the tentacle and has the stunned condition for 1 minute. On a successful save, a creature takes half as much damage only. A stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Psychic Link. Voalsh targets one incapacitated creature she senses with her Creature Sense trait and establishes a psychic link with the target. Until the link ends, Voalsh can perceive everything the target senses. The target becomes aware that something is linked to its mind once it is no longer incapacitated, and Voalsh can terminate the link at any time (no action required). The target can use an action on its turn to attempt to break the link, doing so with a successful DC 21 Charisma saving throw. On a successful save, the target takes 15 (3d6 + 5) psychic damage. The link also ends if the target and Voalsh are more than 5 miles apart. She can form psychic links with up to ten creatures at a time.

Sense Thoughts. Voalsh targets a creature with which she has a psychic link with. Voalsh gains insight into the target’s emotional state and foremost thoughts (including worries, loves, and hates).

Warp Reality. When hit by an attack roll, Voalsh gains a +4 bonus to her AC against that attack roll, potentially causing it to miss. Then Voalsh, along with any equipment she is wearing or carrying, magically teleports up to 60 feet to an unoccupied space she can see.

Voalsh can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature’s turn. Voalsh regains spent legendary actions at the start of her turn.

Break Concentration. Voalsh targets one creature within 120 feet of her with which she has a psychic link. Voalsh breaks the creature’s concentration on a spell it has cast. The creature also takes 2 (1d4) psychic damage per level of the spell.

Psychic Inspiration. Voalsh targets one friendly creature she can sense within 120 feet of her. The target has a flash of inspiration and gains advantage on one attack roll, ability check, or saving throw it makes before the end of its next turn.

Psychic Pulse. Voalsh targets one creature within 120 feet of her with which she has a psychic link. The target and enemies of Voalsh within 30 feet of target take 15 (3d6 + 5) psychic damage.

Sever Psychic Link. Voalsh targets one creature within 120 feet of her with which she has a psychic link. Voalsh ends the link, causing the creature to have disadvantage on all ability checks, attack rolls, and saving throws until the end of the creature’s next turn.

Psionic Anchor (Costs 2 Actions). Voalsh targets one creature she can sense within 120 feet of her and anchors it by sheer force of will. The target must make a DC 21 Charisma saving throw. On a failed save, its speed is reduced to 0, and it can’t teleport. It can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Shatter Concentration (Costs 2 Actions). Voalsh targets a creature she is grappling. The target’s concentration on a spell it has cast or an ability it is maintaining ends, and the target takes 24 (3d12 + 5) psychic damage.

Tentacle Flurry (Costs 2 Actions). Voalsh makes 1d4 + 1 Tentacle attacks.

Dragon's Breath (Costs 3 Actions). Voalsh recharges her Tadpole Brine Breath and uses it.