Illithid Arcanist

Illithid Arcanist is a type of hostile mind flayer character encountered during Act Three of Baldur's Gate 3.

Involvement

Many Illthid Arcanists will appear during several combat encounters at the High Hall and Atop the Netherbrain. Illithid Arcanists have 2 variants: one with  Fire Shield: Chill and Fire resistance, and another with  Fire Shield: Warm and Cold resistance. Their version of  Magic Missile deals more damage, fires more missiles, and has a significantly longer range. This makes them dangerous if not dealt with quickly. If pushed or thrown off the top of the  Netherbrain during the final battle, Illithid Arcanists will simply teleport back to their former position.

Combat

Attacks and actions

 Counterspell ()

Try to stop a spell being cast.

If it is higher level than the spell slot you used to Counterspell, you must make a check using your spellcasting ability^{[See: Bugs]} to prevent it. The check's difficulty is equal to 10 plus the level of the spell you are trying to counter.

This spell can be cast while you are  Silenced.

 Recharge: Per combat

 Extract Brain ()

Damage: 11~101

10d10 + 1⁠Piercing

Healing: 6~36

6d6⁠Healing

Try to extract the brain of a Stunned or Unconscious creature.

 Melee: 1.5 m (5 ft)

 Recharge: Per turn

 Levitate ()

Float effortlessly to a destination.

 Range: 18 m (60 ft)

 Magic Missile ()

Damage: 36~54

6d4 + 30⁠Force

Create six darts of magical force, each dealing 1d4 + 5⁠⁠Force damage to its target.

The darts always hit their target, and can each be targeted individually.

 Range: 30 m (100 ft)

 Mind Blast ()

Damage: 4~32 + modifiers

4d8 + Spellcasting modifier⁠Psychic

Spew forth a conical wave of psychic energy and possibly  Stun targets within.

 INT Save

 Recharge: Long rest

 Mind Flayer Domination ()

Dominate a nearby humanoid. Allies are unaffected.

Each time the dominated creature takes damage, it may repeat the Saving throw against your domination.

 INT Save

 Range: 18 m (60 ft)

 Shield ()

When you are about to be hit by an enemy, use your Reaction to increase your  Armour Class by 5. You also take no damage from  Magic Missile. These effects last until the start of your next turn.

 Range: Self

 Recharge: Per combat

 Tentacle Whip ()

Damage: 6~24

2d10 + 4⁠Psychic

Lash out with your tentacles and possibly Stun your target.

 INT Save

 Melee: 1.5 m (5 ft)

Notable loot

• Random gemstone or alchemy ingredient

Bugs

• Due to an incomplete list of spell checks,  Shield will not reduce the damage of Illithid Arcanist's version of  Magic Missile for the rest of the turn after Shield is used as a reaction.