You’re trekking through the shadow-cursed lands of Baldur’s Gate 3, probably trying to keep your torch lit and your sanity intact, and then you stumble upon Reithwin Town. It’s a mess. Between the shadows that want to eat your face and the general sense of dread, it’s easy to miss the good stuff. Specifically, the stuff you need to keep Karlach from exploding. We’re talking about the infernal iron masons guild location—a spot that sounds straightforward but usually ends up being a source of massive frustration for players who just want to finish their quest lines.
Let's be real. If you’re at the Masons' Guild, you aren't just there for the architecture. You’re hunting for that rare metal. Infernal Iron is the literal lifeblood of Karlach’s heart, and by the time you reach Act 2, you’ve realized that Dammon is basically the only guy in the world who knows what to do with it. But finding it in the guild isn't as simple as opening a chest in the lobby.
Why the Masons' Guild is a Total Headache
The building itself sits just northwest of the Moonrise Towers area, right in the heart of the Reithwin ruins. It looks like a standard, run-down workshop at first glance. You walk in, see some stone slabs, maybe a few shadows lurking in the corners, and you think, "Okay, where's the loot?"
The problem is the verticality and the hidden layers. Larian Studios loves hiding things behind perception checks and secret buttons. Honestly, if your party has a low Perception score, you might walk right past the most important room in the entire zone. Most players breeze through the main floor, grab some low-tier loot, and leave, completely missing the fact that the infernal iron masons guild cache is actually tucked away in the basement.
It’s not just about the iron, though. The lore here is dense. You find out the masons weren't just guys who liked rocks; they were deeply involved in the resistance against Ketheric Thorm. They made a literal pact with a devil just to try and stop the absolute. It’s dark stuff.
Cracking the Basement Secrets
To get to the goods, you need to find the hatch. It’s behind the main counter area. Once you’re down there, things get spicy. You aren't just looking for a box; you’re navigating a tomb of secrets.
There’s a very specific spot on the table in the basement. You’ll see a piece of Infernal Iron just sitting there, mocking you. But don't just grab it and warp out. If you explore further into the back rooms—specifically through the hidden door triggered by the Key-Shaped Lever—you’ll find the records of the mason who basically sold his soul to fight Ketheric.
Wait. Did you check the bones?
Seriously. In this game, loot is everywhere. In the Masons' Guild, the Infernal Iron is usually sitting right on a stone table in the primary basement room, near some blueprints. It’s one of the easiest pieces to get in Act 2, provided you actually bother to go downstairs. If you've already burned through your supply from Act 1 (the Blighted Village or the Shattered Sanctum), this is your primary lifeline for Karlach’s "The Hellion's Heart" quest.
Karlach, Dammon, and the Big Picture
Why do we care so much? Because Karlach is a fan favorite, and her engine is overheating. By the time you reach the infernal iron masons guild, you’ve likely met Dammon at the Last Light Inn. He tells you he can fix her up, but he needs the materials.
If you miss this piece of iron, you’re making life harder for yourself. There are only a handful of pieces in the entire game. You’ve got:
- The one in the Blighted Village (Act 1)
- The one in the Goblin Camp (Act 1)
- The one in the Zhentarim Hideout (Act 1)
- The Masons' Guild piece (Act 2)
- A few scattered bits in the Gauntlet of Shar or dropped by Steel Watchers in Act 3
Basically, if you skip the guild, you're skipping a guaranteed upgrade. It’s also worth noting that Dammon can use extra iron to craft the Flawed Helldusk armor set. It’s not as "god-tier" as the stuff you get later, but for mid-Act 2? It’s a total game-changer for your tank.
The Combat You’ll Probably Face
Don't expect to just waltz in. Reithwin is crawling with shadows. If you haven't dealt with the Shadow Curse—either by getting a Moonlantern or Pixie’s Blessing—you’re going to take constant necrotic damage just standing there.
Inside the guild, there are often Wraiths or Shadows that spawn if you hang around too long. The fight isn't particularly hard if you have a Cleric like Shadowheart (Spirit Guardians is basically a cheat code here), but if you get caught off guard, they’ll drain your Strength and leave you encumbered while you’re trying to carry all that heavy stone-working loot.
Nuance: What Most Guides Get Wrong
People often say the Masons' Guild is "essential" for the quest. Strictly speaking? It’s not. You can finish Karlach’s quest without this specific piece if you found enough in Act 1. However, most players miss at least one piece early on because they were too busy running away from the Owlbear or getting blown up by traps in the Underdark.
Also, people forget about the Infernal Alloy. Don't confuse the two. While the infernal iron masons guild provides the standard iron, there are other materials like enriched iron or alloys that show up later. Stick to the basics for now. Dammon just wants the raw stuff to keep that engine from melting through Karlach’s ribcage.
The layout of the basement is also a bit of a maze. There’s a pressure plate trap near the back—right where the interesting lore notes are. If you’re playing on Tactician or Honour Mode, that trap can genuinely end a run if your party is grouped up too tightly. Send Astarion (or whoever your sleight-of-hand expert is) in solo to clear the way.
Actionable Steps for Your Playthrough
If you're standing in Reithwin right now, here is exactly what you need to do to maximize this location.
First, ensure you have a light source. The Shadow Curse is no joke. Head to the guild coordinates (X:-105, Y:15) and enter the main floor. Don't waste too much time upstairs; the real value is below. Find the ornate wooden hatch behind the counter.
Once you are in the basement, head to the north side of the room. You’ll see a marble table. The Infernal Iron is right there. After you grab it, look for the "Mason's Log" nearby. It gives you a massive amount of context for the "Investigate the Resistance" questline.
Before you leave, check the walls for a button or lever. There is a hidden area containing a very dangerous combat encounter with several shadows and a "Shadow-Cursed Shambling Mound" nearby outside. If you feel underleveled (anything below Level 7), grab the iron and get out. If you're feeling spicy, clear the whole basement for some extra XP and specialized gear like the Shield of Devotion which can sometimes be found or related to the loot tables in this sector.
💡 You might also like: Why Hitman Elusive Target Le Chiffre Still Haunts Players
Finally, take that iron straight back to Dammon at the Last Light Inn. Do not wait. If you progress the story too far—specifically, if you complete the Nightsong quest in the Gauntlet of Shar—the NPCs at the inn might move or... well, let's just say things can go south very quickly. Fix Karlach now so you don't regret it later.