Quick Links
The final battle ofBaldur’s Gate 3puts you up against some of the most iconic Dungeons & Dragons enemies under the control of the Netherbrain and the true enemy of any tactical strategy game: a timer. Racing against the swarming masses of enemies and the falling platforms beneath your feet, you’ll have work cut out for you.
Thankfully, you’re not alone in this fight. With the help of your friends, your summoned allies, and your greatest partner - this guide, you’ll have everything you need to destroy the Netherbrain once and for all. Just…maybe consider bringing Gale along if all goes awry.
How To Reach The Netherbrain
Reaching the Netherbrain, you will need to havecompleted these previous steps:
During all of these steps, there will bea branching path where you’ll determine who your illithid companion isas you cannot progress the final portion of the game without one:
If you choose anyone except the Emperor,you will have to fight himin the final battle against the Netherbrain.
How To Reach The Crown Of Karsus: Defeating The Forces Atop The Netherbrain
Atop the Netherbrain, there will be asmall legion of enemiesstanding between you and the Crown of Karsus. Theseenemies include:
1
4
If you sided with the Emperor
-
16
As you appear, thefirst four on the above list will be on the brain itselfwhile theArcanists will be on the upper back platformand thetentacles are hidden out of viewand only appear when walking in their range.
Tentacles are not affected by area attack spells if they are not already visible. You cannot use spells to reveal the locations of the tentacles.
You’ll notice as you enter this area that there is additionally a timer. This will be atimer to the emergence of a supporting Nautiloid ship.
After the timer’s countdown ends (or on the fifth turn in Tactician), the ship will appear andbegin firing magic artilleryon the brain.Additional reinforcements of illithids and intellect devourerswill come with this ship. However, since this isn’t much of a setback,we recommend not focusing too much on this timer.
Above all else, you should:
Although you should be sparing with your strongest spells, youmay wish to use lower-level spellssuch as:
orany other large area effect spellto take care of any large masses of enemies.
Alternatively, you can bypass the top of the brain entirely withArcane GateorDimension Door. We don’t generally recommend this, however, as this puts you right in the line of fire of the illithid arcanists and doesn’t solve the dragon problem.
Thebest and most consistently effective strategywe’ve used for the opening of this encounter is to:
With the top of the brain mostly cleared near the center, you canstart using low level spells and ranged attacks to draw the aggression of the illithidsup top.
Each Illithid has high-level Magic Missilewhich can kill your party-members as it continues hitting even if your character is Knocked Out. This is highly dangerous, so wewarn extreme caution in your approach.
Black Hole Nebula is a huge asset in drawing the illithid off the crown and away from where you’ll be summoning the portal to the Netherbrain’s domain. Additionally, you can Gather Your Allies up on the platform next to them as the arcanists tend to prioritize these targets more than your party.
How To Defeat The Emperor (Side With Orpheus)
If you sided with Orpheus, you will have to face the Emperor atop the Netherbrain. Although this may seem terrifying at first,there is nothing special about the Emperor’s stats or feats.
If you’re scared of the Emperor, don’t be. He’snothing you haven’t faced before plus some extra spellssuch as Chain Lightning in higher levels of difficulty.
When fighting him, you havemore to fear about the additional possibility of being stunnednext to a dragon and his accompanying dream enemies than you have from a 1v1 encounter with him.
We recommend targeting the Emperor firstwith your strongest ranged attacks to get him off the field on Turn One. You don’t want to be mass-stunned for the first half of the fight.
He does have a Fire Shield (Ice), but sticking to a strong ranged attack on Turn One will negate any issues this would cause.
How To Use The Crown Of Karsus
When you reach the Crown of Karsus on the far side of the brain’s dome, you willneed your illithid in the partytouse the special “Crown of Karsus” action. This can be found on thefar right of your hotbar.
If you take damage during your usage of the Crown of Karsus,you will lose concentrationand have to retry next round.One round is all that will be requiredto open the last half of the final battle.
Using this actionwill cancel out the rest of your turn, so use any second actions or bonus actions before using this feature. Additionally,make sure you aren’t standing on any possible incoming blastsfrom the illithid ship.
15
Huge/10,000kg (Aberration)
14 (+2)
10 (0)
22 (+6)
28 (+9)
21 (+5)
24 (+7)
Use a reaction to release a Brainquake.
Against All Odds (Conditional)
If succeeding the DC100 against the Netherbrain during the last encounter, the Netherbrain begins its fight with 20 percent less HP.
Aegis of the Absolute (Honour Mode Only)
The Netherbrain becomes immune to any type of damage taken until the start of its next turn. Upon such time, the Netherbrain will lose all immunities and begin anew.
Attacks
Retributive Brainquake
After being struck, Netherbrain uses Reaction to cause a Brainquake for 10d6 Psychic damage (or half as much on a successful Intelligence save) on all creatures within 30m. On a failed save, creatures are also Mindbroken and suffer from the banes of Slow.
Orb of Negation
Netherbrain summons an orb that explodes on its next turn for 20d10 Force damage to all within 30m. Platforms under the orb received the condition: “Marked for Negation” and will be removed from the battlefield upon the orb’s detonation.
Orb Of Negation Attack
Before rushing in, it is important to understand the mechanics of the floor of the Netherbain’s inner domain.On the Netherbrain’s turn, it will always use Orb of Negation.
Orb of Negation will highlight a portion of platforms within the Netherbrain’s domain. You will see a new object added to the Turn Order.When the turn of the Orb detonates on its next turn, the highlighted platforms will fall.
Any creatures standing on the platforms when they are destroyed will be automatically killed. Sometimes, characters will still be “Marked for Negation” even if they are no longer standing on a marked platform. This is a rare bug, and we caught an example of it in the video above. You can tell if your character is Marked for Negation if they have a reddish hue glowing around them.
As Orb of Negation will select three (or more) of the platforms each round, you will have limited rounds until the fight is physically impossible to win. The higher your difficulty, the more platforms will be selected and the less rounds you will have.
We recommendwaiting until your party is gathered around the portal and ready to enter immediately.The portal will open the turn after your mind flayer uses the Netherstones on the Crown of Karsus.
If you don’t send all of your party in at once, the platform on the other side might be negated, making it impossible to enter the portal.
Brainquake Attack
Beyond Orb of Negation, theonly other attack the brain has is Brainquake.
This may cause melee attackers to act as if the spell Slow had been cast on them on failed Intelligence Saving Throws. So, you’ll have tobe frugal with your action economyif your characters have suffered a Mindbreak.
Strategy And Methods
Beyond these two warnings, you’ll want toput everything you have into killing the brainas quickly as possible.
It hasno resistances, and it only has immunities in Honour Mode. Therefore, you should be able to do decent damage quickly. However, if you’re struggling,these methods may help:
While attacking, you’ll likely need to move around a lot. Make sure tokeep an eye on your available bonus actions and Movementto ensure you’re not caught in an Orb of Negation and accidentally kill a party-member during the final battle.
Eventually, you’ll put the Netherbrain in its place. But what you do from here will be up to you.
Will youdominate the brainand become the new ruler of Faerun, or will youliberate the citizensbelow of their oppressors and put an end to this elaborate plot once and for all?
