In Baldur's Gate 3, Karlach is a fierce Tiefling barbarian who carries a heavy burden within her chest. Instead of a normal heart, she survives on a volatile piece of machinery known as an Infernal Engine. To secure her future and maintain her presence in your party, players must actively complete her personal questline. This requires tracking down a specific infernal mechanic and securing extremely rare materials scattered across Faerûn.
Locating Dammon and the First Upgrade
Your journey to modify Karlach's mechanical heart begins during Act 1 at the Emerald Grove. Here, you must locate a talented Tiefling blacksmith named Dammon who resides within the Hollow section. He is the only expert available early on who truly understands the complexity of hellfire technology.
Before he can begin the initial repairs, you must provide him with a piece of Infernal Iron. This rare resource can be found hidden in dangerous locations like the shattered sanctum or the blighted village. Handing over the metal allows Dammon to complete the first tune-up, which temporarily stops her engine from overheating.
Advancing the Questline in Act Two
As your party journeys into the shadow-cursed lands during Act 2, you will get another chance to stabilize her internal engine. Dammon can be found setting up a temporary workshop at the Last Light Inn alongside other refugees. You will need to bring him a second piece of Infernal Iron to progress her companion story safely.
This critical second upgrade allows Karlach to finally touch others safely without risking severe thermal burns. Completing this stage is absolutely mandatory if you intend to pursue a romantic relationship with her. Failing to visit Dammon before completing the major story arc of Act 2 will permanently halt your progress on this quest line.
Reaching the Forge of the Nine in Baldur's Gate
The final stage of managing Karlach's dangerous condition takes place once your party successfully enters the massive Lower City during Act 3. Dammon relocates his master blacksmithing business to a prominent location called the Forge of the Nine. He will continue to offer unique crafting options using any additional infernal resources you gather along the way.
While players can find extra pieces of regular or refined infernal iron, the engine cannot be entirely replaced with a mortal heart within the base game. Instead, managing her condition shapes her final choices as you approach the dramatic conclusion of the main narrative. Helping her complete these vital upgrades ensures she stays combat-ready and deeply loyal until the very end.
