Baldur's Gate 3: Walkthrough & Boss Guide
0% complete
🗺️ Main Story Walkthrough
Tick off each step as you go — your progress saves locally, no account needed.
This is a condensed overview of the three acts and five major boss fights, not a full walkthrough. It follows the BG3 Wiki act overviews and boss pages. Baldur's Gate 3 has many branching choices, so only the broad flow and verified boss mechanics are covered here.
Act One begins right after the Nautiloid crashes: you wake on the Ravaged Beach looking for allies and a cure for the mind flayer tadpole in your head. Six companions can be recruited in this act: Astarion, Gale, Karlach, Shadowheart, Lae'zel and Wyll. The Emerald Grove is in turmoil: First Druid Halsin is missing, and Kagha has begun the Rite of Thorns, which would seal the Grove and expel the tiefling refugees. Goblins fighting under the banner of the Absolute, including their leader Minthara, are searching for the Grove, and you can help them or defend it. Entering Rosymorn Monastery concludes the Rite of Thorns.
The Underdark is an optional Act One region. Its areas include the Arcane Tower, the Ebonlake Grotto (the main Myconid colony) and the Dread Hollow, where the Sussur Tree grows; its bark is needed for the Finish the Masterwork Weapon quest. Grymforge is a separate map reached by skiff across the Ebonlake from the Underdark beach; it holds the Adamantine Forge and the boss Grym (see below). Auntie Ethel's lair, reached through the Overgrown Tunnel, is another optional Act One fight. The Blood of Lathander is found on a locked altar in a secret chamber in Crèche Y'llek.
In Act Two the party crosses the Shadow-Cursed Lands to reach Moonrise Towers and the Cult of the Absolute. You can enter the region through the Mountain Pass or the Underdark. The Last Light Inn is a refuge run by the Selunite cleric Isobel, who shields it from the curse. Reithwin Town holds the Grand Mausoleum, the only entrance to the Gauntlet of Shar, the act's major dungeon. Entering the Shadowfell from the Gauntlet is a point of no return: Act One locations become inaccessible and unfinished quests there end automatically. If Shadowheart is in the party, the Spear of Night is obtained from the Silent Library in the Gauntlet of Shar.
Ketheric Thorm, the immortal leader of the Absolute at Moonrise Towers, is fought three times in Act Two. The main fight is on the Moonrise Towers rooftop, after you deal with Aylin (saving or killing her). With Melodia's letter, a DC 10 Persuasion check can make him stand down; without it, the alternative is a DC 30 Intimidation check. Otherwise, when his health falls below 40% he flees into the Mind Flayer Colony beneath the Moonrise Towers prison, and after he falls there the last part of the fight is against the Apostle of Myrkul. Act Two ends once the Absolute leaves the Shadow-Cursed Lands and the party heads toward Baldur's Gate.
Act Three begins when you reach Baldur's Gate, entering through Rivington and then Wyrm's Crossing, with Wyrm's Rock Fortress, where Enver Gortash is being inaugurated, beyond it. The main quests are Gather Your Allies, Get Gortash's Netherstone, Get Orin's Netherstone and Confront the Elder Brain. The Steel Watch are automatons built in the Steel Watch Foundry on the western edge of the Grey Harbour Docks; the prototype was developed by Gondian artificers, who were forced to build them. The Foundry is described as a single point of failure for Gortash's plans, and Disable the Steel Watch can be completed by placing a Runepowder Bomb in the Neurocitor, entering a codeword, or having Zanner Toobin trigger a self-destruct. Every companion has an Act Three quest, and Minsc can join only if Jaheira was recruited in Act Two.
The House of Hope floats above Avernus and is reached through a portal at Helsik's shop, the Devil's Fee. The Orphic Hammer sits in the Archive under a shield that only a codeword removes; the password is in Raphael's Notes in the Boudoir safe. Taking the Hammer raises the alarm, and using the portal afterwards forces the fight with Raphael. Hope, a level 10 Cleric, is chained in Hope's Prison and only the Orphic Hammer can free her; the Gauntlets of Hill Giant Strength are on a pedestal in the Archive, and taking them without permission also raises the alarm. The Boudoir's restoration faucets work like a rest for party members standing in the water but do not work during the Raphael fight.
The finale is the confrontation with the Netherbrain (an Elder Brain), which uses a fleet of Nautiloids during its assault on Baldur's Gate. Phase one is fought atop the brain; phase two takes place inside the Crown. Details are in the boss entry below.
⚔️ Boss Guides
Auntie Ethel (The Hag)
Attack Patterns
The lair fight is in the Overgrown Tunnel, where Mayrina is caged. On her first turn Ethel throws a flammable slime bomb at Mayrina's cage. If her Mask servants are alive she summons them; if they are gone she casts Auntie's Trickery to create illusory clones. Her clones can cast Hold Person, which can paralyze the whole party. She also uses Ray of Sickness, poisonous slime bombs, melee attacks and Vicious Mockery, and can cast A Coven of Hags. In Act Three she poses as Captain Grisly at the Blushing Mermaid, and her copies are invisible.
Strategy
The BG3 Wiki says throwing water onto the cage from range before combat neutralizes the fire at no cost. Any damage dispels a clone, and clones cannot summon more, so remove them fast with Magic Missile, area-of-effect attacks or Void or Spiked Bulbs. To find the real Ethel, examine each one (only she has the Fey Life feature), look at clothing (red for the hag, blue for clones), or note that she always occupies the same turn-order spot.
Grym (Adamantine Forge)
Attack Patterns
Grym guards the Adamantine Forge in Grymforge and activates when someone uses the forge. It has 210 HP on Explorer, 300 on Balanced and 450 on Tactician and Honour. Its Adamantine Skin makes it immune to physical damage and most other damage until it is Superheated by standing in lava. Superheated gives resistance to several damage types, immunity to necrotic, fire, lightning, psychic, poison and radiant, and vulnerability to bludgeoning. Its Slam deals 4d8+7 bludgeoning, and its Quake (3d4 bludgeoning, 12 m radius) knocks targets prone with no height restriction, so high ledges are not safe from it. It has no ranged attacks.
Strategy
Grym attacks whoever hit it last, who is marked as Prime Target, so you can lure it into the lava or under the forge hammer by moving that character. The lava valve creates lava that recedes after two turns. While Superheated and standing on the central anvil, the forge hammer deals 12d8 bludgeoning (doubled by vulnerability) and knocks it prone, which also ends Superheated. Ranged bombardment from safe positions also works because it cannot shoot back, but ledges within Quake range are still at risk. The loot is the Grymskull Helm.
Ketheric Thorm
Attack Patterns
The BG3 Wiki says Ketheric fights like an Oathbreaker paladin, using smite-like attacks, aura spells and undead minions, and issues Deadly Orders to focus fire on targets he considers dangerous. The first rooftop fight takes place after you deal with Aylin. When his health drops below 40% he flees into the Mind Flayer Colony, taking Aylin with him if she is alive. The Colony fight leads into the Apostle of Myrkul.
Strategy
If you have Melodia's letter, a DC 10 Persuasion check can make him stand down; without it the alternative is a DC 30 Intimidation check. Passing several Persuasion or Intimidation checks on the rooftop and in the Colony skips the first half of the Colony fight, after which he gives himself to Myrkul and dies when the Apostle is defeated. The wiki does not recommend specific spells or classes for this fight, so none are given here.
Raphael
Attack Patterns
Raphael is fought in the House of Hope after you take the Orphic Hammer instead of his deal. Four Soul Pillars each give him +1d12 fire damage, +3 Dexterity and a Soul Charge. Breaking a pillar can trigger Fiendish Ascension, and when all four are destroyed he permanently becomes the Ascended Fiend. He is immune to fire, resistant to non-magical slashing, piercing and bludgeoning, and to lightning, cold and poison, and has Magic Resistance. His Punish Divinity reaction stuns anyone who deals radiant damage to him and drains their HP. He is fought alongside Vengeful Cambions, Korrilla and possibly Yurgir.
Strategy
The wiki notes that Consume Souls heals him 3d6 per standing pillar, so destroying the pillars early limits his healing, and that if a party member is downed they gain Severed Soul (disadvantage on attacks and checks) until Restore Soul is used or Raphael is defeated. Hope can join the fight if you completed Save Hope first. Avoid radiant damage because of Punish Divinity.
The Netherbrain
Attack Patterns
In phase one you fight on top of the brain, aiming to reach the Crown of Karsus and channel Karsus' Compulsion. Stepping directly onto the brain's surface summons up to 16 hidden tentacles, so approaching from the side platforms may be safer. Four Illithid Arcanists with long-range Magic Missile, Counterspell and stuns are dangerous, and a Nautiloid arrives after a four-turn countdown and summons Mind Flayers and Intellect Devourers. Phase two takes place inside the Crown: the Netherbrain has 210 HP on Explorer, 300 on Balanced and 450 on Tactician. Orbs of Negation deal damage at the end of the next round and destroy the platform beneath them, and its first attack each round triggers Retributive Brainquake (psychic damage that can slow targets).
Strategy
Channeling Karsus' Compulsion ends the caster's turn and must last until their next turn; if it succeeds, a portal opens. Get the whole party near the portal first, because the final fight starts as soon as it opens, and move off any platform marked by an orb. Only party members, their summons and either Orpheus or the Emperor can enter. Mobility spells such as Dimension Door, Misty Step or Fly help reach the Crown.
Sources & fact-check
Release facts, mechanics and boss details on this page were checked against these sources on 12 October 2026. Spotted an error? Tell us.