Baldur's Gate 3 Adamantine Forge: Moulds, Ore and Grym

The Adamantine Forge in Baldur's Gate 3 sits beside Grymforge in the Underdark, and it lets you craft two pieces of adamantine gear in Act One using two Mithral Ore and any of six moulds. To use it you lower the forge platform, flood it with lava, and drop the great hammer, which also wakes the forge's guardian, the golem Grym. This walkthrough covers the route in, every ore and mould location, the forging steps, the Grym fight and which two items are worth making.

Coordinates, stats and steps here were checked against the bg3.wiki pages for the Adamantine Forge, the quest of the same name, Grym and Grymforge in November 2026.

Where the Forge Is and How to Get There

The forge is in the Abandoned Refuge area next to Grymforge, the duergar-occupied ruin in Act One. The normal way into Grymforge is the skiff from the beach docks of the Decrepit Village in the Underdark, though the Shadow-Cursed Lands route from the githyanki side can also lead there. Once you have visited, two Underdark waypoints open up: Grymforge and the Ancient Forge.

Between the Grymforge docks and the forge is a blocked path. You can clear it through the Get Past the Rubble quest, which uses an iron ladder, levers and a jump across a broken statue, or skip it with Fly, Misty Step or a well-placed Jump near the rubble. Do not confuse it with the separate cave-in trapping the drow True Soul Nere elsewhere in Grymforge, which is a different quest with its own explosives problem. Either route ends at the Ancient Forge waypoint, and you earn experience for reaching the forge itself halfway down the broken staircase.

You do not need to know about the forge to find it, but three sources start the quest early. Freeing the dwarf Dhourn from the Spectator's petrification, or speaking with his corpse, gives you a Memory Shard. Filro the Forgotten carries Scribbled Notes. And Xargrim, beyond the Guardian Gate in the Ebonlake Grotto, carries a book called The Great Furnace of Grymforge disguised as Flumph Mating Rituals. Sages earn an inspiration point for passing the checks on those three hint items.

Finding Both Pieces of Mithral Ore

Every forge recipe consumes one Mithral Ore, and there are only two in the game. That is why you can only make two adamantine items per playthrough, so pick carefully before you start smelting.

• Southwest vein: head southwest from the Ancient Forge waypoint down toward a lava flow. Animated armours attack first, then you jump across rocks in a lava area to reach the vein on the far shore.
• Steps vein: follow the rocks east from the path down to the forge platform. The vein bulges out of an archway in a library-like room, and Magma Mephits ambush you on the way.

Both veins need bludgeoning or force damage to break the ore free. A blunt weapon works, and so does a Warlock's Eldritch Blast. Bring healing potions, because both routes involve a fight and a missed jump into lava hurts.

The Six Moulds and Where They Are

Each craftable item has a matching mould lying somewhere around the forge area. You only need the moulds for the two items you plan to make, but grabbing all six lets you decide at the last moment.

• Longsword Mould: on metal scaffolding along the rubble route.
• Mace Mould: on a table south of the Ancient Forge waypoint.
• Scale Mail Mould: on the ground southwest of the waypoint.
• Scimitar Mould: on a skeleton near the levers.
• Shield Mould: on a skeleton behind a locked door that needs a DC 12 Sleight of Hand check.
• Splint Mould: on a skeleton east of the waypoint.

A mould is not consumed. After the first item, the Mould Ejection Lever pops it back out, so you can put the same mould in again and craft two identical items with your two ores if you want a matched pair of weapons.

How to Forge an Item Step by Step

The forge has four controls: the Mould Chamber, the Crucible, the forge lever that moves the platform and drops the hammer, and the Lava Valve. The order matters.

1. Place one Mithral Ore in the Crucible.
2. Place your chosen mould in the Mould Chamber.
3. Use the forge lever on the south side to lower the platform toward the lava.
4. Open the Lava Valve to flood the area with lava. The first time you do this, Grym appears.
5. After the fight, use the forge lever so the hammer strikes the mould.
6. Pick up your finished item from the Mould Chamber.

For the second item, use the ejection lever, load the second ore and a mould, and repeat. One warning from the wiki: the platform control button raises the platform back up, and if you raise it before making your second item, the forge stops working until you lower it again. If your party includes a Guild Artisan, keep that character in the party when you pick up the first item, because that is when the Art Endures inspiration is awarded.

Beating Grym, the Adamantine Golem

Grym is a level 10 construct with 18 AC and 300 hit points on Balanced, 210 on Explorer and 450 on Tactician and Honour. Its Adamantine Skin makes it immune to almost every damage type until it becomes Superheated by standing in lava. While Superheated it is vulnerable to bludgeoning damage while still resisting slashing, piercing and several elements, so a mace or warhammer user becomes your best attacker.

The intended solution is the forge itself. The hammer deals 12d8 bludgeoning damage, doubled by the Superheated vulnerability, but it only hits if Grym stands on the central anvil, and each strike knocks Grym prone and removes Superheated. The usual rhythm is to open the valve to heat Grym, lure it onto the anvil, drop the hammer, then reheat. Grym marks whoever attacks it as a Prime Target and chases them, so the last person to hit it decides where it walks next. Minor Illusion also lures it onto the anvil.

Grym has no ranged attacks, which makes archers and casters on the upper platforms very effective. Melee attackers get sent Reeling for three turns by Intense Adamantine Backlash unless Grym is Superheated. In Honour Mode it also gains Adamantine Reverberation, 10 temporary hit points that release a thunder shockwave when broken; our Honour Mode guide covers how legendary boss changes like this work. Grym drops the Grymskull Helm.

Two achievements live here. Forged in Blood and Fire is earned by crafting any item, and A Grym Fate requires killing Grym without using the forge hammer at all, which is a real challenge given its immunities. Our achievement roadmap lists which others are easy to miss in Act One.

Prepare before you pull the valve. Long rest first so every spell slot is available, put your bludgeoning damage dealers in the party, and give your ranged characters spots on the raised platforms around the anvil. Hold one character back from attacking until Grym is in position, because whoever lands the last hit becomes its Prime Target and can walk it straight onto the anvil. If a fight goes badly, the lava recedes after two turns, so do not waste attacks on Grym while it is not Superheated; spend those turns repositioning instead.

Which Two Items Should You Make?

All six items share one strong trait: attackers cannot land critical hits on the armor and shield. Beyond that, they serve different builds.

• Adamantine Splint Armour (heavy, 18 AC): Magical Plate reduces incoming damage by 2, and melee attackers are sent Reeling for 3 turns. The best defensive pick for a Paladin, Fighter or heavy-armor Cleric.
• Adamantine Scale Mail (medium, 16 AC): damage reduced by 1 and a 2-turn Reeling backlash. Ideal for Rangers, Barbarians who wear armor, or anyone with medium armor proficiency.
• Adamantine Shield (+2 AC): a Shield Blow reaction can knock melee attackers prone, and attackers who miss are sent Reeling.
• Longsword, Mace and Scimitar: each has Diamondsbane and ignores resistance to its damage type.

Most players make the Splint Armour for their frontliner plus either the Shield or the Scale Mail. Weapons are tempting, but the later acts are full of magical weapons, while an 18 AC suit that blocks critical hits stays useful to the final fight. If you are still deciding who wears it, our class comparison shows which classes get heavy armor, and the feat guide covers Heavy Armour Master and the other feats that suit an armored frontliner.

If You Would Rather Not Farm the Forge

Two ores means two items per run, and testing more combinations means another trip through the Underdark. The Baldur's Gate 3 Mega Mule modded save takes a different approach: it starts a High Elf Paladin with all legendary, very rare, rare and uncommon armor, all weapons, rings and amulets, plus max gold and a camp of level 12 characters, so you can compare loadouts without hunting each piece. You need your own copy of the game, and the store page lists PS5, PC and Xbox.

Other options for the game are collected on the Baldur's Gate 3 store page.

Frequently Asked Questions