Baldur's Gate 3 Act 3 Complete Walkthrough: All Quests, Endings, and Boss Strategy Guide

TL;DR

• Act 3 of Baldur's Gate 3 wraps your 100+ hour campaign with 27 total quests (17 main, 10 side) and 5 distinct main endings + dozens of variations based on your choices
• We break down step-by-step progression, key decision consequences, and min-maxed boss strategies for the final three encounters (Orin the Red, Gortash, Netherbrain)
• We include a full checklist of everything you need to do before starting the final assault to avoid missing unique loot and companion endings
• All ending variations are laid out clearly so you can pick the outcome that fits your playthrough without spoiling yourself unnecessarily

Act 3 Overview: What You're Walking Into

Act 3 opens the second you step through the Lower City gate of Baldur's Gate, and it's the largest, most dense chapter in the entire game. If you're coming off Act 2, expect roughly 30-40 hours of content for a full completionist run, 15-20 for a straight main story push. This Baldur's Gate 3 chapter guide covers every main quest, optional side content, key decision points, and all endings so you don't miss a thing.

The entire act is structured in three clear progression phases:

1. Lower City Exploration: Unlock the Lower City, Wyrm's Rock Fortress, and Rivington, gather allies, take out Orin or Gortash
2. Upper City Access: Storm Wyrm's Rock, unlock the Upper City, confront the Absolute's inner circle
3. Final Assault: Attack the Netherbrain, make your final choice, get your ending

You've got full freedom to do content in almost any order, but following this step-by-step walkthrough ensures you don't lock yourself out of any quests or unique loot.

Step-by-Step Act 3 Progression

Phase 1: Lower City Initial Progression (Start to Getting Ketheric's Netherstone)

When you first enter the Lower City, your first main quest is Find the Entertainer (also called Get Gortash's Netherstone). Follow these steps to stay on track:

1. Speak with the Flaming Fist at the gate → pass the DC 20 Persuasion/Deception check to enter without fighting, or kill them for an easy 400 XP total.
2. Head to Sharess' Caress to meet with Gortash (he'll send you an invite via messenger if you rest after entering). This conversation unlocks the Get Orin's Netherstone and Get Gortash's Netherstone main quests, and reveals Orin has kidnapped Yenna and your companion Lae'zel or Gale depending on your choices.
3. Complete the Search the Cellars side quest in the Lower City to unlock the Undercity and Bhaal's temple entrance. You need a DC 20 Perception check to spot the hidden door in the Lower City Crypt, this is non-negotiable to get to Orin.
4. Gather all allies in the Lower City first before fighting either boss: Recruit the Harpers, the Flaming Fist, Arron Gortash's former associate, and unlock the Steel Watch Foundry to disable the Steel Watch automatons before fighting Gortash. Pro Tip: Disabling the Steel Watch Foundry early removes 6 level 10 Steel Watchers from the Gortash fight, cutting his total HP by 40% (1200 extra HP to burn otherwise).
5. Clear Bhaal's Temple, kill Orin the Red to get her Netherstone. She hits for 2d10+5 slashing damage per attack and has 180 HP total at level 12, so bring piercing damage and keep healers topped off.
6. Clear Wyrm's Rock Fortress, kill Enver Gortash to get his Netherstone. He has 220 HP at level 12 and calls in 2 Steel Watchers if you didn't blow the foundry, so do that first.

Phase 2: Upper City Progression (Netherstones to Final Assault)

Once you have all three Netherstones (Ketheric, Orin, Gortash), you unlock access to the Upper City. Follow this sequence to avoid locking out side content:

1. Complete all Lower City and Rivington side quests before entering the Upper City. A lot of content locks once you start the final assault, we'll give you a full checklist later.
2. Enter the Upper City via the gate behind Wyrm's Rock, head to the Temple of Torm (the Absolute's base) to confront the Emperor and learn the truth about the Netherbrain.
3. Complete all companion personal quests here: Astarion's Ascension, Shadowheart's choice about Shar/Sharran parents, Lae'zel's choice to join the Emperor or fight Vlaakith, Gale's crown choice. All of these directly impact your ending.
4. Gather all Upper City allies: The Knights of the Shield, the Zhentarim, and the remaining Gondians from the Steel Watch Foundry.
5. When you're ready, head to the docks to start the Final Assault main quest. This is the point of no return, so save before you go.

Phase 3: Final Assault and Ending Progression

1. Fight your way up the Netherbrain's mind flayer colony, defeat the final wave of Mind Flayers and illithid parasites.
2. Reach the crown room, use the three Netherstones to subdue the Netherbrain.
3. Make your final choice (more on that in the decision points section below) to get your ending.

Key Decision Points & Consequences

Every major choice in Act 3 changes your ending, companion outcomes, and even rewards. Here's the full breakdown of the most impactful decisions:

Full Ending Tier Ranking

Here's how I rank all 5 main endings based on lore, rewards, and overall satisfaction for a playthrough:

Boss Encounter Strategy Guide

All three major Act 3 bosses have specific breakpoints and strategies that make them trivial if you prepare correctly. Here's the hardcore min-max strategy for each:

Orin the Red (Bhaal's Temple)

• Base Stats (Level 12 Party): 180 HP, 18 AC, 2d10+5 slashing damage per multi-attack, can shapeshift into Bhaal's avatar at 30% HP (adds 60 extra HP, +2 damage per attack)
• Weakness: Piercing damage takes 1.5x, she's vulnerable to radiant damage if you bring the Holy Spear of Dawn you get from Act 2
• Strategy: Send one tank to handle the Bhaal cultist adds, focus all DPS on Orin immediately. Use counterspell on her Fear spell that she casts at 60% HP. When she drops below 30% HP, pop a battle rage or action surge to burn her before she can finish the transformation animation (it takes 2 full turns, you can kill her before it procs if you do 60+ damage in that window).
• Pro Tip: Pass the DC 25 Persuasion check before the fight to force her to fight you 1v1 without adds. That cuts total fight HP from 320 to 180, it's worth the ability slot if you have a high CHA character.

Enver Gortash (Wyrm's Rock Throne Room)

• Base Stats (Level 12 Party): 220 HP, 19 AC, 2d8+3 bludgeoning damage per attack with his mace, can call 2 Steel Watchers (200 HP each) if you didn't blow the foundry
• Weakness: Lightning damage stuns him for 1 turn on a failed DC 18 Con save, he's got no magic resistance so raw burst damage from spells works great
• Strategy: If you didn't blow the foundry, pull the Steel Watchers into the hallway outside the throne room to fight them one at a time, then focus Gortash. Use grease on the stairs to split his adds up. Gortash always uses his first turn to cast Haste on himself, so counterspell that turn 1 to cut his action economy in half.

Netherbrain (Final Boss)

• Base Stats (Level 12 Party): 600 HP core, 3 tentacles (120 HP each), 16 AC, 2d12+4 bludgeoning damage per tentacle attack
• Weakness: Psychic damage does 2x damage to the core, tentacles take extra damage from slashing
• Strategy: Focus one tentacle at a time on turn 1-2, burn them down to get access to the core. When the tentacles are dead, unload all your daily abilities, action surges, and smites on the core. At 20% HP, the Netherbrain will try to mind control one of your party members, so have a counterspell ready to shut that down. Total time limit is 8 turns before he destroys Baldur's Gate, so you need roughly 75 DPS per turn to beat the DPS check, which is trivial at level 12 if you've geared properly.

Notable Loot Locations

Here's all the unique, missable loot in Act 3 that's worth grabbing, sorted by location: