Mastering the Netherbrain Boss in Baldur's Gate 3: Proven Strategies and Tips

Quick Links

Phase Two

The entire narrative of Baldur's Gate 3 builds up to a pivotal moment: the ultimate showdown with the Netherbrain, also known as the Absolute. This formidable Elder Brain has undergone significant transformation from prolonged interaction with the Crown of Karsus, surpassing the danger level of any other Elder Brain within the illithid empire.

As the final boss in Baldur's Gate 3, this battle poses a formidable challenge even for a level 12 party equipped with endgame gear. The second phase of the confrontation is particularly brutal due to the Netherbrain's fighting techniques. However, with a bit of prior preparation, this fight can become significantly more manageable for parties of any composition.

Phase One

In order to give a better result, I need more context about the content fragment and what it is referring to. Could you please provide more information?

Four illithid arcanists thoroughly enjoy unleashing high-level Magic Missiles while also beginning the encounter with an active Fire Shield.

A collection of tentacles manifest when a party member or ally approaches too closely, actively attempting to ensnare anyone within proximity.

After four rounds, a nautiloid will appear. Similar to the previous nautiloid encounter, it will unleash Fire and Force damage on various areas of the battlefield and call for additional support.

In the event that the players declined the Emperor's offer in the Astral Prism, he will join the battle riding atop the red dragon, conjuring a Dream Guardian for every member of the party.

The objective of this battle is to guide the designated illithid party member to the Crown of Karsus located at the far end of the brain. The illithid must then utilize their action to influence the Netherbrain. Restarting becomes necessary if they are affected by Incapacitation, Stun, Polymorph, or Knock Out. Failure to restart triggers the opening of a portal to the psyche of the Netherbrain and initiates phase two. It is important to note that Karsus' Compulsion has a range of 20 feet, necessitating proximity for the caster.

Given the complexity of the situation, players may initially feel overwhelmed. Nevertheless, a well-planned strategy can assist the party in overcoming these challenges and advancing to the second phase.

Players can safely disregard the Dream Guardians as they primarily utilize their turns for teleportation and employing a modified version of the Command spell in an attempt to hinder or silence their designated party member. However, the success rate of this ability is relatively low due to its low save DC.

Conversely, it is crucial not to overlook the Emperor. Whenever feasible, prioritize targeting him initially and strive to swiftly defeat him within a single round.

The red dragon poses a significant threat with its high hit points of 400. It inflicts considerable damage and can target multiple individuals with its flame breath and multiattack. However, one advantage is that its size prevents it from fitting on the metal walkways surrounding the battlefield. Utilizing Hold Monster can immobilize the red dragon, while allies summoned through spells or Call Forth Allies can divert its attention.

Successfully defeating the red dragon rewards players with the achievement Interfectorem Draconis.

The tentacles have the ability to manifest in various areas of the brain, excluding the metal walkways. To access the Crown of Karsus, players must send certain party members onto the walkways.

Summoning reinforcements becomes even more crucial due to the illithid arcanists' tendency to target the individuals closest to them.

The tentacles have the ability to halt a character in the middle of a jump by materializing, however, they are ineffective against individuals who are teleporting, levitating, or flying.

Here's the key tip: it is crucial to assemble the party at the Crown of Karsus prior to utilizing Karsus' Compulsion. This approach will significantly simplify phase two.

Phase Two

Activate Karsus' Compulsion to access the Netherbrain's Psyche. Characters will materialize on a random platform situated approximately 60 to 70 feet from the Unbreakable Will of the Netherbrain. The objective of this phase is to inflict 200 damage to the UWN within five rounds. Failure to do so will result in the Netherbrain transforming the party into mind flayers, abruptly ending the game.

Although the UWN remains stationary, it possesses two methods to harm the party. One such method is its Psionic Retribution reaction, which deals Psychic damage to the attacker and any adjacent party member, along with inflicting the Mindbroken condition. Fortunately, the UWN can only utilize this reaction once per round.

Secondly, the UWN possesses the capability to generate Orbs of Negation during its turn. Activation of these orbs requires one turn and results in inflicting Psychic damage. However, their primary purpose is to demolish adjacent platforms. If any party member is present on these platforms when they vanish, death is imminent. Thankfully, the affected platforms emit a distinctive red glow, facilitating easy identification. It is crucial to ensure the safety of any Mindbroken characters before initiating attacks.

Due to the UWN's continuous destruction of platforms, the difficulty level of this battle escalates with each passing round. Hence, it is advisable for players to gather all party members in close proximity to the Crown of Karsus prior to opening the portal. By overwhelming the UWN with their full arsenal during the initial round of phase two, the party has the potential to vanquish it before it even has the chance to create a single Orb of Negation.

Content must be written in English:

Another aspect influencing the battle is the players' performance in their initial encounter with the Netherbrain. Although even a natural 20 on a DC 99 check won't result in an instant victory, it will trigger a special condition called "Against the Odds" that reduces the UWN's starting hit points.

After the Unbreakable Will of the Netherbrain is defeated, the party's illithid will attempt to either destroy or dominate the Netherbrain. If the illithid is not the main character, players have the option to betray them and choose the alternative. Regardless, the next step in the game is to have a discussion with the party about what comes next.

Baldur's Gate 3 is available now on macOS, PC, and PS5.