eXputer
Subscribe

Locationmajor

Adamantine Forge

The Adamantine Forge is an ancient Sharran forge hidden deep beneath Grymforge in the Underdark.

Importancemajor

Key takeaways

  • The Adamantine Forge is a distinct subarea of the Abandoned Refuge, adjacent to Grymforge rather than synonymous with it.
  • There are only two pieces of Mithral Ore, so the party can forge only two items in total.
  • Six moulds are available longsword, mace, scimitar, shield, scale mail and splint armour.
  • Grym is vulnerable only while Superheated, a condition produced by opening the lava valve.
  • The forge hammer can damage Grym for substantial bludgeoning damage if the construct is lured onto the central anvil.
  • The surrounding area contains a second Mithral Vein, hostile Magma Mephits, a Lava Elemental and the route to the Sentient Amulet.

About this guide

Spoiler warning: This guide covers Act One locations, the Adamantine Forge quest, the Grym boss encounter, the forge’s limited crafting resources and several optional items in the surrounding Abandoned Refuge.

Overview

The Adamantine Forge is an ancient Sharran forge hidden deep beneath Grymforge in the Underdark. It is one of Act One’s most valuable optional locations because it allows the party to turn Mithral Ore and one of six moulds into powerful adamantine armour, shields or weapons.

The forge is not simply a room inside Grymforge. In geographical terms, the forge is a distinct location within the broader Abandoned Refuge, which lies south-east of Grymforge. The Ancient Forge Waypoint belongs to the Abandoned Refuge and sits beside the route to the forge, but it is adjacent to the Adamantine Forge rather than inside it. This distinction matters when following maps, quest descriptions or location directories.

The forge is protected by Grym, a massive construct created by the gnome artificer Silouv Yali. Defeating Grym is optional in the broad sense that the party can leave the area without using the forge, but it is the central combat challenge associated with the location and rewards the party with the Grymskull Helm.

The wider area

The forge is reached through Grymforge, the ruined Sharran fortress in the Underdark. Grymforge contains the duergar settlement, the cave-in trapping Nere, the Dormitory, the central industrial ruins and the mechanical route leading south towards the abandoned areas.

Beyond the southern end of Grymforge lies the Abandoned Refuge. This is a separate but connected landmass overlooking the inaccessible Ancient Temple. It contains the Ancient Forge Waypoint, abandoned armour piles, the route into the forge, the lava-filled side areas and the Crumbling Island.

The Adamantine Forge proper begins beyond the broken stairs south-east of the waypoint. It consists of the giant circular forging platform, the central crucible and anvil, the hammer mechanism, the lava valve and the surrounding ledges used during the Grym encounter.

Included subareas

The following areas are relevant to the Adamantine Forge location and its immediate associated region:

Forge platform

The platform begins in its raised position. Operating the forge lowers it towards the lava and exposes the arena for the boss encounter. The forge’s written operating instructions describe a four-stage process: insert ore and mould, lower the hammer, open the lava valve, then strike the forge again.

Forge approach and study

The path from the Ancient Forge Waypoint leads through broken masonry and abandoned industrial structures. A side area resembling a study or library contains a Mithral Vein, scrolls and an Elixir of Fire Resistance. Approaching the area triggers an encounter with Magma Mephits, normally in two waves.

Lava Lake and Crumbling Island

West of the forge is a lava-filled side area containing a small Crumbling Island. An Adamantine Chest on the island contains the Sentient Amulet, an item associated with the Help the Cursed Monk and Talk to the Sentient Amulet quests. A hostile Lava Elemental patrols the area.

The Lava Lake is dangerous even outside combat. Lava can apply the Melting condition, while bubbling lava may create Fire surfaces. The Lava Elemental is the source of the unusual movement and bubbling in the area, according to successful passive Nature or Arcana checks.

Named location directory

Parent and neighbouring locations

The Ancient Temple is a neighbouring, inaccessible location overlooking the area. It should not be treated as part of the forge or as an explorable subarea of the Abandoned Refuge.

---

Parent and neighbouring locations

Standard route from Grymforge

The usual route begins after entering Grymforge by duergar boat from the Underdark. From the central Grymforge area, proceed south through the ruined industrial sections and the mechanisms used to cross the broken platforms.

The route is deliberately vertical and fragmented. A character may need to jump across gaps or use a movable platform while the rest of the party remains behind. Once one character activates the Ancient Forge Waypoint, the rest of the group can use it to regroup.

The route commonly involves

  1. 01
    Travelling south from the main Grymforge chamber.
  2. 02
    Crossing or bypassing the grated mechanical paths.
  3. 03
    Navigating the movable iron platforms.
  4. 04
    Jumping across broken masonry and the remains of a statue.
  5. 05
    Operating the paired levers near the ruined stairway.
  6. 06
    Reaching the Abandoned Refuge.
  7. 07
    Activating the Ancient Forge Waypoint.
  8. 08
    Travelling south-east down the broken stairs to the forge.

Shortcut options

The rubble and machinery can be bypassed with suitable movement abilities. Depending on the character’s statistics and available spells, the following can shorten the journey:

One commonly used shortcut begins near the far end of the hall containing Nere’s cave-in. A character can use Misty Step, Fly or a sufficiently strong jump to reach the area near the Ancient Forge Waypoint, then teleport the remainder of the party. This bypasses much of the mechanical route, but it does not remove the forge’s combat or resource requirements.

Suggested exploration route

This route reduces backtracking and ensures that the party knows how to reach both Mithral Veins before committing its limited resources.

---

The Adamantine Forge has no resident civilian population or ordinary shopkeepers. Its named and notable inhabitants are hostile creatures or historical figures connected to the forge’s construction.

For a thorough first visit

  1. 01
    Clear the route through Grymforge far enough to access the southern platforms.
  2. 02
    Collect moulds encountered in Grymforge before travelling deeper.
  3. 03
    Activate the Ancient Forge Waypoint.
  4. 04
    Search the study-like side area and defeat the Magma Mephits.
  5. 05
    Mine the Mithral Vein near the library.
  6. 06
    Explore the lava route towards the second Mithral Vein.
  7. 07
    Visit the Crumbling Island if you want the Sentient Amulet.
  8. 08
    Return to the forge platform.
  9. 09
    Prepare the party before inserting the first mould and Mithral Ore.
  10. 10
    Defeat Grym.
  11. 11
    Forge the second item after the battle if you have not already done so.

Grym

Grym is the forge’s guardian, a powerful construct created by Silouv Yali from magma and adamantine. It is the main boss of the location and appears when the forge is activated and lava enters the crucible.

Grym’s Adamantine Skin makes it immune to damage until it becomes Superheated. Opening the lava valve allows lava to flow around the arena and applies Superheated to Grym. While Superheated, Grym becomes vulnerable to bludgeoning damage and can be struck by the forge hammer.

Grym’s attacks and movement are governed by its Threat Assessment and Prime Target mechanics. When the construct is attacked, it tends to focus on the creature marked as its Prime Target. This allows the party to lure Grym onto the central anvil beneath the hammer.

Grym’s reward

The helm is obtained after defeating Grym.

Lava Elemental

A hostile Lava Elemental patrols the lava-filled side area near the Crumbling Island. It is a separate encounter from Grym and is not part of the forge activation sequence.

Magma Mephits

Magma Mephits appear in the library-like side area and can also be summoned during or after the Grym encounter, depending on how the fight develops. The side-area encounter is separate from the forge boss battle.

Historical figures

Silouv Yali

Silouv Yali was a gnome known for wizardry and engineering. The Sharrans recruited or converted him, and he redesigned the forge so that it could heat Mithral Ore to produce adamantine equipment. His greatest achievement was Grym, the construct created to guard the forge.

Sister Ansar

Sister Ansar was a Sharran priestess who converted Silouv Yali to the faith of Shar. She is part of the forge’s history rather than a present-day NPC.

Ketheric Thorm’s Dark Justiciars

The Dark Justiciars later occupied and developed Grymforge. The forge had previously been built by Sharran followers, but the Justiciars used it for their own military purposes. An Orthon eventually eliminated the Dark Justiciars in the area, after which the forge fell into darkness again.

Historical character directory

The last four entries are historical or story-associated rather than present residents of the forge.

---

How the mechanism works

Insert the mould into the mould chamber and the ore into the crucible. Pull the forge lever to lower the platform. Open the lava valve to flood the arena. Once the forge is active, the hammer can be triggered to complete the item.

The forge can produce two items in total because the game contains only two pieces of Mithral Ore for this purpose. The party may use the same mould twice, but it cannot create more than two items altogether.

Craftable items

The Adamantine Scale Mail also sends melee attackers Reeling when they hit the wearer. The Adamantine Splint Armour applies the same idea with a stronger duration. The shield can send attackers Reeling when they miss and provides a reaction that can knock a melee attacker prone after a hit.

Craftable items

MouldCrafted itemMain benefit
Longsword MouldAdamantine LongswordIgnores slashing resistance and treats attacks against objects as critical hits
Mace MouldAdamantine MaceIgnores bludgeoning resistance and treats attacks against objects as critical hits
Scimitar MouldAdamantine ScimitarIgnores slashing resistance and treats attacks against objects as critical hits
Shield MouldAdamantine ShieldPrevents critical hits against the wearer and can knock melee attackers prone
Scale Mail MouldAdamantine Scale MailAC 16 medium armour, reduces incoming damage by 1 and prevents critical hits
Splint MouldAdamantine Splint ArmourAC 18 heavy armour, reduces incoming damage by 2 and prevents critical hits

Which two items should you forge?

The best choice depends on party composition, proficiency and build requirements.

Strong general-purpose choices

The armours are usually the safest choices because their critical-hit protection and damage reduction remain useful throughout Act One and into Act Two. Splint Armour is especially valuable for a proficient heavy-armour character, while Scale Mail is suitable for medium-armour users.

The shield is attractive for a front-line character who already has a strong weapon and wants defensive utility. Its value depends on having a character proficient with shields.

When weapons make sense

The longsword and scimitar address slashing resistance, while the mace addresses bludgeoning resistance. These weapons do not automatically outperform every other weapon available in Act One, so their value is more build-dependent than the defensive items.

---

There are two Mithral Veins associated with the forge area. Each vein yields one piece of Mithral Ore rather than a large stack, making the resource strictly limited.

Strong general-purpose choices

First Mithral Vein

The first vein lies south-west of the Ancient Forge Waypoint, near the lava route. Reaching it involves crossing or navigating around dangerous terrain. Animated Armours may become hostile during the approach.

Second Mithral Vein

The second vein is found east of the route descending towards the forge, in or near the library-like area. Approaching it triggers Magma Mephits.

Second vein directory entry

The veins are vulnerable to bludgeoning damage. Force damage, including suitable spells or explosives, can also be used to break them and obtain the ore.

---

All six moulds are found in or around Grymforge and the route to the Ancient Forge Waypoint. The moulds are not all inside the Adamantine Forge itself.

Longsword Mould

Found high above the central Grymforge chamber on an overhanging metal bridge or scaffolding.

Longsword Mould

NameDetails
LocationGrymforge upper metal bridge
CraftsAdamantine Longsword
AccessRequires navigating the elevated industrial route

Mace Mould

Found near the Ancient Forge Waypoint, on a table or nearby platform.

Mace Mould

NameDetails
LocationGrymforge or Abandoned Refuge approach, near the waypoint
CraftsAdamantine Mace

Scale Mail Mould

Found on the ground near the Ancient Forge Waypoint, close to a standing torch.

Scale Mail Mould

NameDetails
LocationNear the waypoint
CraftsAdamantine Scale Mail

Scimitar Mould

Found on a skeleton near a ruined stairway with two levers, overlooking the rubble and the route towards Nere.

Scimitar Mould

NameDetails
LocationGrymforge ruined stairway
CraftsAdamantine Scimitar

Shield Mould

Found on a skeleton at the top of the Dormitory stairs, behind or near a locked door.

Splint Mould

Found near the Ancient Forge Waypoint on a rock ledge overlooking lava pools.

The six mould locations and their corresponding recipes are documented separately from the forge itself, which is important because several moulds must be collected before reaching the crafting platform.

---

Splint Mould

NameDetails
LocationAbandoned Refuge, near the waypoint
CraftsAdamantine Splint Armour

Starting the battle

The first forging sequence summons Grym. The construct emerges once the forge is activated and lava enters the crucible. The party is then confined to the arena until the encounter is resolved or the combat is otherwise ended.

Grym’s weaknesses

Grym cannot be damaged normally while its Adamantine Skin is active. Opening the lava valve applies Superheated, which makes Grym vulnerable to bludgeoning damage and permits the forge hammer to damage it.

Hammer strategy

The forge hammer deals 12d8 bludgeoning damage when it strikes Grym while the construct is Superheated and standing on the central anvil. Because Superheated also makes Grym vulnerable to bludgeoning damage, the hammer is one of the most efficient ways to end the fight.

The hammer removes the Superheated condition after striking, so the lava must normally be reapplied before the next damaging hammer blow.

A practical sequence is

  1. 01
    Activate the lava valve.
  2. 02
    Attack Grym or otherwise make it focus on a chosen Prime Target.
  3. 03
    Move the Prime Target across the central anvil.
  4. 04
    Wait for Grym to follow.
  5. 05
    Trigger the hammer lever.
  6. 06
    Reopen the lava valve when necessary.
  7. 07
    Repeat until Grym is defeated.

Melee and ranged alternatives

If the party does not want to rely on the hammer, use bludgeoning attacks while Grym is Superheated. Ranged characters can also manipulate the encounter from elevated positions, but the arena’s Quake attack can still affect characters on high ledges.

A character with Minor Illusion can sometimes lure Grym onto the central anvil. The construct’s low Intelligence makes it particularly vulnerable to this approach, although positioning and line of sight remain important.

Magma Mephits during the boss fight

Magma Mephits may appear after the forge hammer damages Grym or once the fight has progressed sufficiently. Keep at least one character prepared to handle them, especially if the group is concentrating on keeping Grym beneath the hammer.

---

Sentient Amulet

The Sentient Amulet is found in an Adamantine Chest on the Crumbling Island in the lava area west of the forge. It is not a crafting component and should not be confused with the moulds or Mithral Ore.

The chest is reached through hazardous lava terrain and is guarded by the Lava Elemental’s patrol route.

The amulet begins the or relates to

Elixir of Fire Resistance

An Elixir of Fire Resistance can be found in the library-like area near the second Mithral Vein. It is particularly useful before either the Lava Elemental encounter or the Grym fight, though its protection does not make the lava itself safe to stand in.

Scrolls and study loot

The study-like room contains several scrolls and forge-related material. The area is also connected to the history of the Sharran smiths and the construction of Grym.

Forge-related documents

The Great Furnace of Grymforge gives the practical operating instructions. It can be found on Xargrim’s corpse in a hidden room in Ebonlake Grotto, rather than inside the forge itself. Before being recognised, the book may appear under a different title and can transform after an ability check.

---

The forge was probably constructed alongside Grymforge by ancient Sharran followers. Its exact age is unknown, but an inscription suggests that it predates Ketheric Thorm’s arrival by several centuries.

Later, the Dark Justiciars of Shar took control of the complex. Sister Ansar converted Silouv Yali, a gnome renowned for wizardry and engineering, to Shar’s faith. Yali redesigned the forge so that it could heat Mithral Ore to the temperatures required for producing adamantine equipment.

Yali’s true masterpiece was not the forge itself but Grym, the construct assigned to guard it. The project consumed much of the available adamantine, leaving insufficient ore for the Sharrans’ planned armaments. This explains why only two usable pieces of Mithral Ore remain in the present day.

After an Orthon eliminated the Dark Justiciars, the forge was abandoned again. By the time the party reaches it, the mechanism remains operational but the surrounding complex has become a ruin populated by hostile creatures and the construct’s lingering guardian.

Background inspiration and setting context

The forge’s history is closely connected to Shar, the Dark Justiciars and Ketheric Thorm’s earlier activities. It is not the same place as the later Gauntlet of Shar, although both locations share Sharran architectural and religious associations. The Adamantine Forge belongs to Act One’s Underdark and Grymforge sequence, while the Gauntlet is a separate Act Two location.

---

Leaving Grymforge

The forge is optional. The party can leave Grymforge and continue the game without crafting adamantine equipment. However, the two pieces of Mithral Ore and all six moulds are limited opportunities, so leaving without collecting them may mean permanently missing the associated equipment for that playthrough.

Nere and the Grymforge state

Grymforge changes after major progression events, particularly after dealing with Nere and leaving the region. The forge route and its resources remain separate from the central Nere quest, but the surrounding settlement may no longer contain the same NPCs or encounters. If you want to explore the entire region, collect moulds and resolve side activities before making a final departure.

Crafting limit

The party can create only two items because there are only two Mithral Ore pieces. This is not a cooldown or a forge durability system. It is a fixed resource limit. The same mould can be used twice, but doing so means giving up two different recipes.

Honour Mode

Honour Mode changes aspects of the Grym encounter, including legendary actions and encounter behaviour. The general principles remain the same: apply lava, exploit Superheated, use bludgeoning damage and position Grym beneath the hammer. Certain control spells, including Command or Silence, may have additional tactical value in this mode.

---

---

Is the Adamantine Forge inside Grymforge?

Not exactly. It is reached through Grymforge but is located in the separate Abandoned Refuge area. The Ancient Forge Waypoint is also in the Abandoned Refuge and is adjacent to the forge.

Can I craft more than two adamantine items?

No. There are only two pieces of Mithral Ore available for the forge, allowing two items in total. You may craft two copies of the same item if you have the relevant mould, but you cannot exceed two finished items.

Do I have to defeat Grym to use the forge?

Grym is summoned when the forge is activated and lava enters the crucible. The boss encounter is the intended central challenge, and defeating Grym is the reliable way to continue using the forge and claim the Grymskull Helm.

Which two items are best?

For most parties, one or both armours are the safest choices because they prevent critical hits and reduce incoming damage. Adamantine Splint Armour suits heavy-armour users, while Adamantine Scale Mail suits medium-armour characters. Adamantine Shield is also a strong defensive choice for a shield user. Weapons are more dependent on proficiency and build.

Can Grym be killed without using the hammer?

Yes. Grym can be attacked with bludgeoning damage while Superheated. The forge hammer is usually the most efficient method, but it is not the only one.

Is the Sentient Amulet part of the forge quest?

No. It is found in the same wider Abandoned Refuge region, on the Crumbling Island, but it is connected to the Help the Cursed Monk and Talk to the Sentient Amulet quests rather than the Adamantine Forge crafting objective.

---

Sources