Baldur’s Gate 3: Adamantine Forge, Mithral Ore and Grym

Reach the Ancient Forge waypoint

The Adamantine Forge is an optional crafting area inside Grymforge, reached by boat through the Underdark. From the Grymforge docks, climb toward the upper area where duergar are using deep rothé to break a rubble wall. Clear that blockage, follow the raised path and watch for traps on the walkway.

Climb down the iron ladder to the suspended metal walkways. The moving platforms and their levers carry you toward the southern ruins. Leave someone at the controls while another character crosses, or use a ranged attack on an accessible lever. Follow the southern walkway and jump down to activate the Ancient Forge waypoint. You can then bring the rest of the party directly to it.

A character with enough jump distance, Fly or Misty Step can also cross from the ledge east of the main cave-in. Activating the waypoint is the useful goal: you do not have to make every party member repeat the platform puzzle.

Collect ore before spending it

Each craft consumes one Mithral Ore. There are two deposits in an ordinary playthrough, giving you two crafted items total. The mould can be reused; the ore cannot.

Deposit	Route from Ancient Forge
Southwestern lava channel	Pass the animated armour area, follow the rocks southwest and jump across the lava to the large blue vein.
Eastern cavern wall	Start down the steps toward the forge, then branch east across the rocks. Magma Mephits ambush the approach to this vein.

Break the vein with a damaging attack, then pick up the ore it drops. Bludgeoning damage works well, and force damage can also break it. A particular named pickaxe is not required. Confirm that you collected the small dropped item before leaving the deposit.

Choose a mould your party can use

Six moulds are scattered around Grymforge. You only need the one for your chosen item, though collecting others gives you more options for the second craft.

Mould	Landmark
Longsword	On the high metal walkway used during the approach.
Scimitar	On a skeleton beside the levers controlling the southern moving platform.
Shield	On a skeleton upstairs inside the locked dormitory.
Mace	On the table close to the Ancient Forge waypoint.
Scale Mail	On the ground southwest of that waypoint, near the animated armour.
Splint	On the raised ground northeast of the waypoint, near a skeleton.

Check equipment proficiency before committing ore. Scale Mail is medium armour; Splint is heavy armour. A character who cannot use the chosen armour properly is a poor recipient, even if its displayed Armour Class looks attractive. Shields and weapons also need to fit the intended character’s equipment setup.

Operate the forge in this order

1. Put one Mithral Ore into the central Crucible.
2. Insert your chosen mould into the Mould Chamber beside it.
3. Pull the Forge Lever to lower the platform.
4. Separate the party onto raised dry sections, then turn the Lava Valve.
5. Handle Grym, who appears the first time lava is released.
6. Use the Forge Lever with the forge heated, then collect the finished item from the Mould Chamber.

The forge’s channels fill with damaging lava. Keep characters out of those channels before opening the valve; a party clustered at the bottom can be hurt before the boss has attacked.

Use Superheated and Prime Target against Grym

Grym’s protection prevents damage until it gains Superheated by standing in lava. While heated, it is vulnerable to bludgeoning. Keep one character able to operate the valve because the lava recedes during the fight.

The central hammer can deal heavy damage. Have a character across the anvil attack Grym, watch the Prime Target marker, and lure it onto the hammer’s impact area. Avoid changing its target with another attack after you have lined up that movement. Once Grym is heated and in position, clear your own characters from the centre and trigger the Forge Lever. Ranged attacks can operate the lever too.

A hammer strike removes Superheated, so lure Grym back through lava before trying another damaging hit. Magma Mephits can join the fight; leave a party member free to handle them rather than committing everyone to the lure.

Honour Mode adds Adamantine Reverberation, with temporary hit points, increased movement and a knockback burst when those points are removed. Keep extra distance from the lava edges and recheck the target’s conditions after each attack.

Make the second item

Loot Grym’s Grymskull Helm separately from the crafted equipment. To change your next craft, use the Mould Ejection Lever, insert another mould and add the second ore. You can also reuse the original mould to make a duplicate. Grym does not respawn for the second craft.

If controls seem inactive, check that the platform is lowered and that both a mould and fresh ore are loaded. Retrieve the first finished item before beginning another cycle. Finish your crafting here before following the Act One route onward into the Shadow-Cursed Lands.