The Adamantine Forge

Key takeaways

The forge rewards careful preparation. Decide which equipment mould is worth using before starting the encounter, because the crafting material and mould determine the resulting item.

• Bring both a mould and Mithral Ore The forge cannot produce equipment from the mould alone. A mould must be placed in the mould chamber and Mithral Ore must be added to the central crucible before the mechanism can be used. Materials
• The lever starts the guardian encounter Pulling the forge lever activates the machinery and triggers Grym. Complete exploration and positioning first, because the battle takes place around the forge platform. Activation
• Use lava to expose Grym Grym needs to be superheated by the lava flow before the guardian becomes vulnerable. Manage the lava system rather than treating the fight as an ordinary armored-enemy encounter. Lava
• Use the forge hammer as a weapon The hammer mechanism can damage Grym when the guardian is positioned on the anvil beneath it. Luring Grym into the correct area is the central tactical challenge. Hammer
• Choose the mould according to the party The available moulds produce different weapons and armor pieces. Adamantine armor is often the safest general-purpose choice because of its protection against critical hits. Mould choice

Overview

The Adamantine Forge is one of Act One's major optional challenges: a dangerous crafting site in Grymforge where Mithral Ore and equipment moulds can be turned into rare adamantine gear.

The Adamantine Forge is located in the Grymforge area of the Underdark in Baldur's Gate 3. Its central purpose is both practical and narrative: the party can use the abandoned forge to create powerful equipment, but operating it also awakens Grym, the mechanical guardian that protects the chamber. The quest therefore combines exploration, item selection, environmental interaction and a difficult arena battle.

To use the forge, place an equipment mould into the mould chamber and put Mithral Ore into the central crucible. Pulling the forge lever activates the mechanism and begins the encounter with Grym. The crafting process is not separate from the boss fight: the same platform, hammer mechanism and lava system form the battlefield, so preparation before activation matters.

Grym is most effectively handled through the forge's environment rather than a conventional damage race. Lava makes the guardian vulnerable, while the forge's hammer can deal substantial damage when Grym is positioned beneath it. The encounter becomes much more manageable when the party controls the lava flow, keeps its distance from the guardian's attacks and uses the arena's vertical layout deliberately.

The quest's main material rewards are adamantine weapons and armor pieces made from the available moulds and Mithral Ore. Defeating Grym also provides the Grymskull Helm. Adamantine armor is particularly valuable because its passive benefit prevents critical hits against its wearer, making the forge an attractive destination even for parties that are not following every side story in Grymforge.

Where this sits

Requirements

Reach Grymforge, locate the forge, and bring the materials needed to operate it.

• RequiredAccess to GrymforgeThe forge is located in Grymforge, an area of the Underdark. The party must be able to explore the area and reach the forge chamber.
• RequiredAn equipment mouldPlace a suitable mould into the mould chamber before activating the forge. Different moulds produce different adamantine equipment pieces.
• RequiredMithral OreAdd Mithral Ore to the central crucible. Without the ore, the forge cannot create adamantine equipment.
• RecommendedBattle preparationPrepare healing, defensive resources and a party arrangement that can operate mechanisms while surviving a difficult mechanical guardian encounter.

Objectives

1. Find the Adamantine ForgeExplore Grymforge in the Underdark and reach the forge chamber.
2. Collect an equipment mouldLocate a mould compatible with the forge and decide which resulting weapon or armor piece best suits the party.
3. Place the mould in the mould chamberInsert the chosen mould into the forge before starting the mechanism.
4. Add Mithral Ore to the central crucibleUse Mithral Ore at the crucible so the forge has the material required for crafting.
5. Activate the forgePull the forge lever to operate the machinery and trigger the guardian encounter.
6. Defeat GrymControl the lava flow, make Grym vulnerable and use the forge hammer when the guardian is positioned beneath it.
7. Claim the forge rewardsCollect the crafted adamantine equipment and Grym's notable drop after the encounter.

WalkthroughSpoilers

1. 01

   Find the Adamantine Forge

   Reach Grymforge in the Underdark

   Travel through the Underdark until you reach Grymforge, then explore the area for the route toward the Adamantine Forge. Do not rush straight to the lever; use the time before activation to inspect the chamber, locate the controls and prepare the party.

   Location: Grymforge

   TipFinish nearby exploration and collect useful moulds or Mithral Ore before beginning the guardian encounter.

2. 02

   Collect an equipment mould

   Search for an equipment mould

   Look through Grymforge for one of the moulds that can be used by the Adamantine Forge. The mould determines the item produced, so compare the possible weapon and armor results with the needs of the current party before inserting one.

   Location: Grymforge and the forge approach

   Watch outOnce a mould and Mithral Ore are committed to the forge, the resulting craft is tied to that selection; choose deliberately.

   Missable
3. 03

   Obtain Mithral Ore

   Collect Mithral Ore

   Find Mithral Ore in the forge area and keep it available for the central crucible. The ore is a separate requirement from the mould, so having only one of the two items does not complete the crafting setup.

   Location: Grymforge

   TipIf the party is still exploring, gather the materials before pulling the lever so the encounter does not interrupt the preparation route.

4. 04

   Insert an equipment mould

   Place the mould in the chamber

   Approach the mould chamber and insert the chosen equipment mould. Confirm that the intended mould is selected, because this step determines whether the forge creates the weapon or armor piece you want.

   Location: Adamantine Forge

5. 05

   Add Mithral Ore to the crucible

   Load the central crucible

   Use Mithral Ore on the central crucible after the mould is in place. The forge now has both components required for crafting, but the machinery and its guardian encounter still need to be activated.

   Location: Adamantine Forge

6. 06

   Activate the forge

   Pull the forge lever

   Activate the forge by pulling its lever. The platform descends and the machinery starts, bringing Grym into the arena; keep party members positioned so that at least one character can respond to the environmental controls.

   Location: Adamantine Forge platform

   Watch outThis action triggers the difficult fight against Grym. Save or otherwise prepare before using the lever if the party is low on healing or badly positioned.

   Checkpoint
7. 07

   Make Grym vulnerable

   Open the lava flow

   Use the forge's lava control to flood the arena. The lava superheats Grym and makes the guardian vulnerable, so the battle should be managed around keeping this condition active rather than relying only on normal attacks.

   Location: Adamantine Forge arena

   TipTreat the lava control as part of the boss's vulnerability cycle. If the lava recedes, look for the control rather than continuing to attack an invulnerable target.

8. 08

   Position Grym under the hammer

   Lure Grym beneath the hammer

   Position a character or use the party's movement to draw Grym toward the central anvil beneath the forge hammer. Keep enough distance to avoid being trapped by the guardian while making sure Grym ends its movement in the hammer's striking area.

   Location: Central anvil of the Adamantine Forge

   Watch outDo not place the whole party together on the anvil. Grym's close-range pressure and the environmental hazards can punish a group that has no safe route away.

9. 09

   Strike Grym with the hammer

   Trigger the forge hammer

   When Grym is standing on the anvil and is vulnerable from the lava, activate the forge hammer mechanism. The strike is the encounter's signature tactic and can inflict heavy damage, but it only works when Grym is correctly positioned.

   Location: Forge hammer mechanism

   TipUse one character to draw Grym into position and another to operate the hammer when possible, reducing the chance that the lure character must cross the arena twice.

10. 10

    Defeat Grym

    Repeat the lava-and-hammer cycle

    Continue controlling the lava and repositioning Grym beneath the hammer until the guardian is defeated. Avoid spending your best attacks while Grym is not vulnerable, and keep the party spread enough to recover if the guardian closes on one member.

    Location: Adamantine Forge arena

    Checkpoint
11. 11

    Claim Grym's reward

    Search the defeated guardian

    After Grym falls, inspect the remains and collect the Grymskull Helm. This boss reward is separate from the item produced by the mould and Mithral Ore, so check both the guardian's drop and the forge output.

    Location: Adamantine Forge arena

    Missable
12. 12

    Claim the forged item

    Collect the crafted adamantine equipment

    Retrieve the equipment created by the forge and equip or distribute it according to the party's build. Adamantine armor is especially useful for characters who benefit from protection against critical hits.

    Location: Adamantine Forge

Mission mechanics

The forge uses a simple two-part recipe: a mould defines the finished equipment, while Mithral Ore supplies the material. Both components must be loaded before activation. Because the mould is effectively the selection screen for the reward, the party should inspect the available options before committing to the mechanism.

The boss arena is also a puzzle. Grym is not intended to be fought only through ordinary attacks; the lava flow changes the guardian's vulnerability, and the forge hammer provides the most important environmental attack. The party must divide attention between survival, control of the lava and positioning Grym on the anvil.

The encounter rewards role separation. One character can attract Grym and guide its movement, while another handles the mechanism when the timing is right. Characters who remain away from the center can provide support and preserve a retreat route, making the fight less vulnerable to a single positional mistake.

The quest also has a meaningful resource decision. Mithral Ore and the selected mould become an adamantine item, while defeating Grym supplies an additional reward. This makes the forge worth completing even when the party is primarily interested in exploration rather than the history of the abandoned site.

What works and what does not

Encounter phasesSpoilers

1. 1

   Activation and arrival

   Starts: Pulling the forge lever after loading the mould and Mithral Ore

   Not applicable before the guardian enters

   The forge begins operating and Grym enters the arena. This is the last transition from preparation to combat, so party placement and access to the controls matter immediately.

   • Close-range guardian pressureTell Grym advances toward characters in the arena.Answer Keep the party mobile and use the arena's space rather than allowing everyone to be surrounded.
   • Keep at least one character able to reach the environmental controls.
   • Do not begin this phase while the party is already in a poor position.
2. 2

   Superheated vulnerability cycle

   Starts: The arena is flooded with lava

   Vulnerable while superheated

   Lava changes Grym's defensive state and creates the opportunity to damage the guardian. The party should spend this phase controlling the guardian's location and preparing the hammer strike.

   • Arena hazardTell Lava covers parts of the forge platform.Answer Move carefully, avoid unnecessary crossings and maintain a route away from the center.
   • Guardian approachTell Grym moves toward the party member drawing its attention.Answer Use that movement to guide Grym toward the anvil instead of retreating without a plan.
   • Do not waste the main attack cycle while Grym is not vulnerable.
   • Use separate roles for luring Grym and activating the hammer when possible.
3. 3

   Hammer strike

   Starts: Grym is vulnerable and positioned on the central anvil

   Reduced by the forge hammer and other valid attacks

   The hammer can damage Grym when the guardian is beneath it. Timing is more important than pressing the mechanism immediately, because a missed strike loses the arena's strongest advantage.

   • Hammer timing windowTell Grym stands on the anvil while the lava condition is active.Answer Activate the hammer only after confirming that Grym is inside the striking area.
   • Keep the lure character moving so Grym follows the intended route.
   • Leave room for the hammer operator to escape after the strike.
4. 4

   Final defeat and loot

   Starts: Grym is reduced to zero health

   Defeated

   The guardian falls and the battle ends. Search Grym for the Grymskull Helm, then collect the equipment created by the forge.

   • Check both the boss remains and the forge output before leaving the chamber.

Grym encounterSpoilers

• Location
  Adamantine Forge arena in Grymforge
• Health
  Not listed; Grym is a powerful mechanical guardian whose durability makes the environmental mechanics central to the fight.

Before starting the encounter, spread the party and identify who will manage the environmental controls. Flood the arena with lava, draw Grym onto the anvil, and trigger the hammer when the guardian is correctly positioned. Repeat the cycle while keeping the party away from unnecessary lava exposure and preserving a retreat path.

Completion checklist

• Reach Grymforge and locate the Adamantine ForgeThe forge is in the Underdark section of Grymforge.
• Inspect the available equipment mouldsChoose the item that best fits the current party.
• Collect Mithral OreThe ore is required in addition to the mould.
• Place the mould in the mould chamberConfirm the selected mould before activation.
• Load Mithral Ore into the central crucibleThis completes the crafting setup.
• Prepare the party before pulling the forge leverHealing, positioning and control assignments are especially important.
• Activate the forgeThis begins the encounter with Grym.
• Flood the arena with lavaThe lava condition makes Grym vulnerable.
• Lure Grym onto the central anvilThe hammer requires correct positioning.
• Strike Grym with the forge hammerUse the environmental mechanism during the vulnerability window.
• Defeat GrymRepeat the lava and hammer cycle as needed.
• Collect the Grymskull HelmSearch Grym after the battle.
• Collect the crafted adamantine equipmentCheck the forge output before leaving.

Collectibles and quest materials

• 01
  Equipment moulds

  Where: Grymforge and the Adamantine Forge approach

  Moulds determine which adamantine weapon or armor piece the forge creates. Search the surrounding area before committing one to the mould chamber.

  Missable
• 02
  Mithral Ore

  Where: Grymforge

  Mithral Ore is placed into the central crucible and consumed as the material for crafting an adamantine item.

  Missable
• 03
  Grymskull Helm

  Where: Grym's remains in the Adamantine Forge arena

  A notable reward obtained by searching the defeated mechanical guardian.

  Missable
• 04
  Adamantine equipment

  Where: Adamantine Forge output

  The completed weapon or armor piece is determined by the mould used with Mithral Ore.

  Missable

Failure conditions

• The party is defeated by GrymThe guardian encounter is difficult and can end in a total party defeat if the group ignores the lava, hammer and positioning mechanics.
• A character is overwhelmed in the arenaA single isolated character can be placed under heavy pressure if the party lacks a retreat route or allows Grym to reach the group without preparation.
• The wrong mould is committedSelecting a mould that does not suit the party can reduce the practical value of the crafting reward. Inspect the available options before activation.
• The party leaves the area before claiming rewardsThe crafted equipment and Grymskull Helm should be collected from the forge and Grym before the party moves on.

Rewards and dropsSpoilers

• Grymskull Helm
  Dropped by Grym after the mechanical guardian is defeated.
• Adamantine weapon
  A weapon can be crafted when the appropriate weapon mould is combined with Mithral Ore.
• Adamantine armor
  Armor can be crafted with the relevant armor mould and Mithral Ore. Its valuable passive benefit includes protection against critical hits.
• Adamantine equipment
  The exact crafted item depends on the mould selected before the forge is activated.

AftermathSpoilers

Trivia

• The Adamantine Forge serves as both a crafting station and a boss arena, making its environmental machinery central to the quest rather than decorative.
• Grym's vulnerability is controlled by the forge's lava system, while the hammer mechanism provides the arena's most distinctive offensive tool.
• The forge's history is connected to the Sharran faith and the Dark Justiciars, adding a religious and historical layer to the otherwise mechanical encounter.
• The quest's reward is partly determined before the boss fight: the selected mould controls the type of adamantine item produced.

Relationships