Baldur's Gate Wiki

Mind Flayers, also known as Illithids, are monsters with innate Psionic Ability and their dreaded multi-tentacled melee attack that can "devour brain" (temporarily drain intelligence) or kill if the target's intellect is reduced to zero. They are initially encountered during the Shadows of Amn campaign.

Some are found in the Athkatla sewers in the Mind Flayer's Lair, in the mind flayer dungeon in the Underdark main caverns and specifically the Eastern Tunnels, in Watcher's Keep Illithid Encampment and in Sendai's Enclave and the Sendai's Lair Mithykyl area. More are encountered in the Enhanced Edition during the Hexxat's request questline within the Crypt of Durkon.

Some other types include the highly magic-resistant and spell-casting Ulitharids, vampiric illithids and the Alhoon.

An Umber Hulk group is often found in areas with Mind Flayers and they carry no gold nor drop any treasure.


While entering or joining a battle, Illithids typically use their innate psionic abilities to attack the party from a distance, potentially charming one or stunning several teammates. They tend to engage stunned victims in melee to devour their brains. Their melee attacks do negligible damage but drain 5 points of Intelligence on hit. Because creatures die when one of their Ability Scores drops below 1, a Mind Flayer may kill a low-intelligence companion such as Minsc in just two melee hits. The intelligence drain wears off on its own after 30 seconds. Mind Flayers are often accompanied and protected by Umber Hulks, who always use their Confusion ability while joining a battle and will use it again during combat. On rare occasions, Mind Flayers may also attempt to cast Maze on the closest party member if they happen to be critically wounded.

A bit of detail about the Mind Flayer Psionic attacks: The psionic attacks are ranged, cannot be interrupted and have a casting time of 1. As they are not spells, but psionics, a Spell protection such as Globe of Invulnerability or Spell Deflection has no effect on them. These attacks also ignore magic resistance. Both the Psionic Blast and Psionic Domination abilities can be negated by a saving throw. Once targeted and attacked by a Mind Flayer, there is a brief period of time for the innate psionic ability's projectile to travel to the target.

Note: It may seem that a player under haste or otherwise having fast movement could "outrun" this projectile, but that is not the case. Once targeted and launched, the projectile will track and hit the target. Even closing a door quickly in front of the projectile will not stop it. This is a game engine implementation mechanic and can't be changed.


Protection against mind-affecting status effects[]

Mind Flayers' ranged psionic attacks inflict Stun, Charm, Maze, on targets who fail their saving throws. In addition, their pet Umber Hulks can inflict Confusion.
These status effects make party members easy pickings for the Mind Flayers' melee attacks (see the next section), so take precautions.

Here are some ways to protect against all these status effects:

Various other measures protect against only some of these status effects:

Surviving Intelligence Drain Attacks[]

  • Use ranged weapons to pelt Illithids from afar.
  • Boost intelligence of party members likely to engage in melee, perhaps with a Potion of Genius or Potion of Mind Focusing, or both. Refrain from exposing party members with 10 or less intelligence, as only two Devour Brain hits in a 30 second span could kill that character.
  • Use summoned creatures to distract the Mind Flayers and then attack the monsters at range while the summons "keep them busy". Mordenkainen's Sword creatures are particularly effective and impervious to normal Mind Flayer attacks.
  • Mirror Image and Reflected Image image spells will help reduce the chance of being hit in melee combat, at least for a short period.
  • Increase your Armor Class rating, since Mind Flayers have a mediocre THAC0 and will miss more often than not. If a party member can get their adjusted AC rating to -5 or greater, the Mind Flayer will most likely need to roll a 20 in order to connect with a melee strike.
  • Greater Restoration can heal intelligence drain. Or move an affected character to the back row until it has worn off (30 seconds).
  • Concentrate on killing one Mind Flayer as rapidly as possible. Speedy kills are better for the party's survival than spreading damage around to multiple opponents.

Become Practically Invincible against Mind Flayers[]

  • Protection From Magical Weapons (level 6 Mage spell) + Chaotic Commands (level 5 Priest spell) => Become practically invincible against Illithids and their Umber Hulk pets for a short time. The mage spell can only last 4 rounds per cast, but it will completely block melee attacks from Illithids and Umber Hulks, thereby also protecting its caster from Devour Brain. The priest spell last 1 turn per caster level, protecting its receiver from Psionic Blast, Confusion and Domination.

General observations[]

  • Mind Flayers are vulnerable to the same mind-affecting effects that they can inflict on others. They may be stunned or dominated either via weapon effects or by using disabling spells. Charm and Stun effects that bypass magic resistance can be used.
  • Regular Mind flayers cannot target an invisible or unseen player. They also cannot target a player with their single target ranged psionics under Improved Invisibility even after the effect has been changed to "weak" invisibility by some kind of action by the party member.
  • Additionally, as Mind Flayers are 90% or more resistant to magic, spells that do not bypass magic resistance are probably not going to work. The Mind Flayers are also completely protected from Elemental Damage with 100% resistance. Both of those defensive realities mean that many spells are not good or reliable attack options.
  • Mind Flayers are not protected from poisoning or poison damage.
  • Mainly, mind flayers can be swiftly destroyed with melee or missile attacks, to which they have no special defense.
  • One of the greatest risks for a player is to be swarmed and engage two or more Mind Flayers at once in melee combat. As the creatures have at least 4 attacks per round, the probability of several critical hits (and thus automatically connecting regardless of the target's Armor Class rating) upon the player is a real issue. This means that all of the player's intelligence could be drained quite rapidly. It is entirely plausible that if you are "tanking" with a party member, that four Illithids could engage the player at once.
  • Should a party member be affected by a status effect that makes them Helpless, such as being stunned, they are at extreme vulnerability to being killed by the Mind Flayer's Devour Brain attacks. All melee attacks will hit the party member.
  • The Mind Flayer AI scripts are not flexible or particularly "smart". For example, they will attempt to Psionically Stun players under Chaotic Command, or melee attack a player with PFMW on. They may not be able to figure out how to get out of a Cloud based attack, and just remain in it. A party can take advantage of this rigid AI by employing a patient and cautious approach. The party can methodically take down Mind Flayers without undue risk. Be advised that new and other tactics are necessary if playing with SCS, as the Mind Flayers have advanced AI scripts and Dimension door powers.
  • Plan ahead and use your party and specific members wisely. Ensure you have the correct and adequate number of buffing spells necessary before entering a Mind Flayer area. Have a plan to utilize traps and snares - as setting an ambush and leading the enemies into these traps is very possible.
  • There seems to be a misconception on the internet forums that the Skeleton Warrior is immune to the Mind Flayer's Devour Brain attack. Although this creature is a good summon against the Illithid, because it isn't affected by Confusion, Stun or Domination status effects, the creature can be destroyed by intelligence drain effects. It would however take 4 hits by a Mind Flayer to destroy this creature with the Devour Brain attack.

Notable Illithids[]


Mod content[]

Mods icon This section is about unofficial content that is only available via fan-made mods.

Installation of the Sword Coast Stratagems Mod has a specific component you can select that is focused on the Illithid, listed as "Smarter Mind Flayers" (BG2, BG2EE, BGT, EET). From the Mod's Readme:

This component improves the intelligence of the mind-flayers and their kin (specifically, it upgrades flayers, ulitharids, vampiric illithids, and the Master Brain). It allows the illithids to use a somewhat wider range of abilities than before (notably, they have access to a few physical psionic attacks, like Ballistic Attack, and they can astrally travel to more convenient bits of the battlefield); it significantly improves their targeting; it allows them to use each power every 2-4 rounds and choose the most appropriate available power; it lets them avoid attacking targets who are immune to their abilities or to their physical attacks. The component also makes a few changes in how psionic powers work. It mildly increases the damage done by physical psionic attacks (though not to anything like the extent that Tactics does) and it changes "anti-psionic" items so that they do not protect from physical psionic attacks. (On my interpretation, "Ballistic attack" involves using psionics on a rock, not on a PC). This gives illithids a few more options when facing enemies who are shielded from mental attack. The component also systematizes illithid magic resistance and level, so that all of them are 90% magic resistant (previously there were a few exceptions) and the same level. As of version 16, it allows illithids' detonation power to destroy skeletons automatically (in accordance with the 2nd edition rules, as it happens).

The Mind Flayers described on this wiki page now have the following innate Psionic Ability powers, all of which can be used every 2-4 rounds:

With this mod and the "Smarter Mind Flayers" component installed, the differences between the original and EE game experience are noticeable during gameplay. The AI is significantly better. Mind Flayers will Astrally travel (Dimension door) adjacent to party members, especially unprotected ones in the rear, or left alone in a rear area. The illithids will use an Improved Invisibility power, often being invisible from the outset, and attacking from that state. Other changes include making the illithid a 12-HD creature, and their base THAC0 is improved to 12 for their melee attack. Also, the 100% elemental resistances are removed (again, to match up with the D&D 2nd edition ruleset).

Mod gallery[]


External links[]