She escaped ten years in Avernus and her reward is a heart that burns her alive from the inside. Karlach might be the most heartbreaking companion in all of Baldur’s Gate 3.
Karlach is consistently ranked among the most beloved companions in BG3 and for good reason. She combines raw combat power, genuine emotional depth and one of the most consequential storylines in the game. Every choice you make around her quest has real stakes that carry through to the final moments of the campaign.
This guide covers everything you need for Karlach where to find her, the best Barbarian build, how to keep her alive through the infernal engine quest, how to romance her and all four of her endings explained without confusion.
Quick Answer
Karlach is a Tiefling Barbarian companion in Baldur’s Gate 3 with an infernal engine in her chest that is slowly killing her. The best build is Berserker Barbarian with Great Weapon Master feat. Her romance requires 20 plus approval in Act 1 and two Infernal Iron upgrades through Dammon. She has four unique endings depending on your choices.
How to Recruit Karlach and Avoid Missing Her?
Karlach is found on the Risen Road in Act 1 northeast of the Blighted Village. She is being hunted by a group of false paladins led by Anders who works for Zariel and is trying to drag her back to Avernus.
You must resolve the conflict between Wyll and Karlach carefully. Wyll has a warlock pact that drives him to kill her. Using Detect Thoughts on Anders to expose his deception or simply refusing to let Wyll kill her secures Karlach’s recruitment successfully.
Siding with the Tieflings and Druids at the Emerald Grove in Act 1 is critical because it keeps Dammon the Tiefling blacksmith alive. Without Dammon you cannot upgrade Karlach’s infernal engine and her questline becomes impossible to complete.
Best Karlach Barbarian Build
Building Karlach as a top tier Barbarian focuses on maximizing her melee damage output through strong stat distribution and subclass synergy. Choosing between the aggressive Berserker or utility focused Wildheart shapes her combat role, while prioritizing Strength ensures consistent heavy hits across every encounter.
Berserker vs Wildheart Subclass
The best Karlach build uses the Berserker Barbarian subclass because Frenzy and Mindless Rage make her the premier melee damage dealer in the game. Wildheart is a viable alternative for players who want more utility but Berserker consistently produces higher damage output.
Starting stats after respec should prioritize STR at 17 then use Hag’s Hair to push to 18 if possible. CON should be 16 as Barbarian HP scales with CON modifier every level. DEX at 14 meets the medium armor cap and should not exceed that number.
The core stat priority is STR over CON over DEX. Every level up decision should strengthen this priority rather than diversifying into other attributes that do not benefit her role.
Essential Feats, Weapons and Soul Coin Usage
The best feat at Level 4 is Great Weapon Master which enables a minus 5 to hit and plus 10 damage toggle alongside a Bonus Action attack on kill or critical hit. This feat transforms Karlach from a strong melee fighter into one of the most dangerous damage dealers in the entire party.
The best weapon in Act 1 is the Everburn Blade obtained from Commander Zhalk on the Nautiloid. In Act 3 the Balduran’s Giantslayer found in the Counting House vault doubles the STR modifier on damage against Large and Huge creatures.
Soul Coins fuel Karlach’s Infernal Fury ability, granting bonus fire damage during Rage. Much like the high-tech cybernetic enhancements in our Motoko Kusanagi guide, managing these mechanical boosts requires strategic timing. Collect every Soul Coin throughout the game and save them specifically for tough boss encounters.
The Hellion’s Heart Quest: Fixing the Infernal Engine
Karlach’s infernal engine quest is the most important companion questline in Act 1 and Act 2. Completing it correctly is required for her best ending and for the romance to fully progress.
Finding Infernal Iron in Act 1 and Act 2
Infernal Iron locations in Act 1:
- Blighted Village basement in a locked chest
- Shattered Sanctum goblin camp in Dror Ragzlin’s treasure room
- Underdark Grymforge in a crate near the Adamantine Forge area
You need at least two pieces of Infernal Iron total one for the first engine upgrade in Act 1 and one for the second upgrade in Act 2. Finding more than two gives you flexibility but two is the minimum required for the questline.
Keeping Dammon Alive Across All Three Acts
Dammon appears in three locations across the game the Emerald Grove in Act 1, the Last Light Inn in Act 2 and the Forge of the Nine in Baldur’s Gate in Act 3. He must survive each location to perform the engine upgrades.
The most common way to lose Dammon is by siding with the goblins or allowing the Emerald Grove to fall in Act 1. Always defend the Grove. In Act 2 keep the Last Light Inn from being overrun. In Act 3 Dammon is easier to protect but check his location before triggering major city events.
How to Romance Karlach Step by Step?
Romancing Karlach requires consistently building high approval through compassionate choices while progressing her personal questline across all three acts. Fixing her infernal engine with Dammon is the essential catalyst that allows physical touch and unlocks her romantic camp scenes.
Building Approval to 20 Plus in Act 1
The threshold that matters for romance is 20 plus approval by the end of Act 1. The romance does not actually begin in Act 1 it begins in Act 2 after the second engine upgrade.
The highest approval actions in Act 1 include defending the Emerald Grove, allowing Dammon to upgrade the engine, killing Anders and his false paladin crew and using Detect Thoughts to expose Anders’ deception. Each of these actions grants plus 10 approval.
The Act 1 nighttime campfire confession tied to 30 plus approval is currently bugged in Patch 6 and does not trigger reliably without mods. Do not rely on this scene to initiate the romance.
Triggering the Romance in Act 2
Continue gathering Infernal Iron and give any spares to Dammon. After the second upgrade you can trigger the romance in Act 2 by speaking to Dammon again and then progressing through the camp long rest scenes that follow.
If the Mizora complication arises in Act 2 through Act 3 explicitly choose to stay with Karlach rather than following Wyll’s pact obligations. Attending the Singing Lute date with Karlach in Act 3 is also required for the best ending.
Karlach is comfortable with companions sleeping with Halsin and does not disapprove of this choice. She is one of the most accepting companions in the game regarding relationship dynamics among party members.
Karlach Companion Approval and Disapproval Choices
Karlach approves of compassion, protecting the innocent and standing up against cruelty. She disapproves of selfish choices, unnecessary violence against innocents and abandoning people who need help.
Key approval gains:
- Defending the Emerald Grove and talking to Zevlor plus 10
- Allowing Dammon to upgrade the infernal engine plus 10
- Killing Anders and his false paladins plus 10
- Standing against gnome slave masters near Nere plus 5
- Pledging to kill goblin leaders to save the Grove plus 5
Karlach disapproves strongly of siding with goblins, harming Tieflings and making choices that benefit yourself at the expense of vulnerable people. Her approval system rewards the same general heroic approach that benefits the game’s best outcomes.
All Karlach Endings Explained
Karlach has four possible endings: turning her into a Mind Flayer, allowing her to go to Avernus alone to survive, going to Avernus with her as the player character and Wyll going to Avernus with her.
The Mind Flayer Transformation
Choosing to let Karlach become a Mind Flayer allows her to control the Elder Brain and survive. This ending sacrifices her identity and personality to preserve her existence making it the most morally complex of the four options.
Returning to Avernus
If Karlach’s engine cannot be stabilized she must return to Avernus where the infernal environment slows the deterioration. She can go alone, with Wyll or with the player character depending on your choices through Act 3.
The ending where the player goes to Avernus with Karlach is exclusive to a completed romance and requires decisions that start in Act 1 and stay consequential all the way to the final fight. This is widely considered her most emotionally satisfying conclusion for players who fully committed to her storyline.
The Burning Ending
If you do not complete the engine repairs or make specific choices Karlach burns out entirely after the final battle. This is the most tragic outcome and the one most commonly encountered by players who did not know the Dammon questline existed until it was too late.
Is Karlach Better Than Shadowheart for Romance?
Both romances are genuinely excellent but they offer very different emotional experiences that suit different player preferences.
Karlach offers warmth and hope with Tieflings as found family and emotional intensity. Shadowheart offers moral ambiguity with a crisis of faith that has two equally valid resolutions depending on your choices.
Karlach’s romance is the most emotionally intense with the most heartbreaking potential outcome. Shadowheart’s romance allows more player agency in shaping who the character becomes. Neither is objectively better they reward different approaches to emotional storytelling.
Conclusion
Karlach rewards every player who takes the time to understand her questline. The infernal engine quest, the approval system and the ending choices all connect into one of the most emotionally complete companion stories in modern RPG history.
Prioritize the Emerald Grove, find Infernal Iron early and keep Dammon alive through every act. Those three habits secure her best ending options before Act 3 closes off your choices permanently. Start with those and the rest of her story follows naturally.
FAQs
Where do I find Karlach in BG3?
She is on the Risen Road in Act 1 northeast of the Blighted Village being hunted by Anders and his false paladins.
Can you stop Karlach from dying?
Yes completing two Infernal Iron upgrades through Dammon unlocks the Avernus endings that prevent her from burning out.
Is Karlach a demon?
No she is a Tiefling who was sold into service in Avernus making her a victim of Zariel rather than a demon herself.
Can Karlach become a Mind Flayer?
Yes choosing this option at the end allows her to survive by controlling the Elder Brain at the cost of her identity.
Does Karlach mind if you sleep with Halsin?
No Karlach is one of the most accepting companions regarding relationship choices among party members.
Is Karlach harder to romance than other companions?
No she is actually one of the more accessible romances as long as you complete her engine quest and maintain positive approval through Act 1 and Act 2.
