The Netherbrain

The Unbreakable Will of the Netherbrain
The Netherbrain
Stats
Level 20
STR 14 (+2) DEX 10 CON 22 (+6) INT 28 (+9) WIS 21 (+5) CHA 24 (+7)
Race	Aberration
Type	Aberration
HP	300
AC	15
Movement Speed	0
Size	Huge
Weight	10000 kg / 20000 lbs
Initiative	-15
Passive features
Psionic Retribution
Character information
Faction	Absolute
Allies	Absolute
Enemies	The Emperor (dependent), Orpheus
Model

The Netherbrain is the final boss of Baldur's Gate 3. It is an Aberration.

Conditions

•  Chains of Karsus - After using Karsus' Compulsion on the Netherbrain
•  Against All Odds - If a natural 20 was rolled while trying to dominate the Netherbrain at the Morphic Pool it will have this condition, which will give it reduced HP for the encounter.

Attacks and Abilities

 Retributive Brainquake

• As a reaction to taking damage, do 10d6Psychic damage to all enemies within 30m and  Mindbreak them.
• Intelligence saving throw to halve damage.

 Orb of Negation

• Summon several floating orbs which deal 20~200Force damage to everything within range at the end of the next round.

Tactics

Accessing the Netherbrain

• Dimension Door, Arcane Gate and Misty Step are all useful spells to have assigned or distributed as scrolls for moving from the entrance to "Atop the Netherbrain", over to the Crown of Karsus.
• Stepping anywhere on the brainy surface will summon tentacles, so it may be easier to approach from the two platforms on either side. Otherwise, if intending to sprint across, using a character who can avoid Opportunity Attacks, such as one with the Mobile feat.
• Globe of Invulnerability is also useful for protecting the caster of Karsus' Compulsion. However, the nearby Mind Flayers will still be able to  stun creatures inside the globe, which ends the spell prematurely.
  • Tossing Mind Flayers over the edge with moves like Telekinesis will not kill them, as they will just reappear atop the Netherbrain.
• Only party members can enter the Netherbrain's Psych (or The Unbreakable Will of the Netherbrain), so once the portal is open it is no longer necessary to continue fighting other enemies.

Fighting the Netherbrain

• With Tactician, the Netherbrain will have 450 hit points.
• The Netherbrain's hit point total can be reduced initially from rolling a natural 20 for the final skill check in the Morphic Pool
• For each round, the first attack against the Brain will cause it to use Retributive Brainquake which will damage everything in range
• The Brain will use Orb of Negation to summon several orbs which cause damage at the end of the next round. These orbs will destroy the platforms beneath them, so it is important to move characters off of any marked platforms. Further, the brain should be quickly killed before all platforms are destroyed.

Related quests

• Confront the Elder Brain
  • Destroy the Elder Brain
  • Control the Elder Brain

Achievements

Hero of the Forgotten Realms
Save the day: kill the Netherbrain and destroy the Absolute tadpoles.

Absolute Power Corrupts
Reign with terror: take control of the Netherbrain and bend the world to your will.

Sins of the Father
Claim your Throne of Blood: take control of the Netherbrain for Bhaal and break the world.

External Links

The Netherbrain on the Forgotten Realms Wiki

Gallery

• 

  Concept art

• 

  Illusion

• 

  Crown of Karsus close-up