A normal playthrough contains two Mithral Ore veins around the Ancient Forge, so you can make exactly two Adamantine items. The forge accepts six mould types: Splint Armour, Scale Mail, Shield, Longsword, Mace and Scimitar. For most parties, the long-lived defensive pieces — Splint Armour, Scale Mail and especially the Shield — age better than the weapons because anti-critical effects, damage reduction and Reeling remain useful after ordinary weapon enchantments have moved on.
Quick answer: there are only two crafts, so choose before you spend the ore
The first time you open the Lava Valve, Grym appears. Grym is immune to damage until standing in lava gives it Superheated. While Superheated it becomes vulnerable to Bludgeoning, and the forge hammer can deal 12d8 Bludgeoning before vulnerability doubles the hit. The catch: the hammer immediately removes Superheated, so every hammer cycle needs the lava state restored.
Grym only becomes meaningfully damageable after lava applies Superheated; check the status before spending your best actions.
Before touching the forge: collect the ore and the moulds you actually want
One Mithral vein sits southwest of the Ancient Forge waypoint beyond Animated Armours and lava rocks; the other is east of the path down toward the forge, near the Magma Mephit ambush. Each giant vein leaves only one usable ore when broken. Bludgeoning works well on the vein, and Force damage such as Eldritch Blast or smokepowder can also open it.
Each Mithral vein yields one ore; there are only two, which is why the craft decision is permanent for a normal run.
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| Mould | Current location around Ancient Forge | Usually worth a Mithral? |
|---|---|---|
Splint Armour | East of the Ancient Forge waypoint near a skeleton | Yes if you have a heavy-armour frontliner. |
Scale Mail | Southwest of the Ancient Forge waypoint on the ground | Yes when medium armour is the better party fit. |
Shield | Behind a locked door at the top of the stairs, near a skeleton | Excellent broad-value choice for any shield user. |
Longsword | Metal scaffolding around the forge approach | Niche; often replaced sooner than the defensive pieces. |
Mace | Table south of the Ancient Forge waypoint | Niche resistance/object utility. |
Scimitar | Skeleton near the levers on the forge approach | Niche; take only for a specific weapon plan. |
Moulds are physical items. Pick up the mould for the craft you want before lowering the platform and starting the boss sequence.
How to operate the forge — correct order
1. Put one Mithral Ore into the central Crucible.
2. Insert the desired mould into the Mould Chamber.
3. Pull the Forge Lever on the southern side to lower the platform.
4. Open the Lava Valve. The first use summons Grym.
5. After the boss is dead and lava is available, pull the Forge Lever so the hammer shapes the item.
6. Loot the finished item from the Mould Chamber. Use the Mould Ejection Lever if you want a different second craft.
7. Repeat with the second ore. Do not leave assuming the first item was the only one available.
The Mould Chamber and Crucible are separate interactables; a missing ore or missing mould is the most common reason the forge appears unresponsive.
The Mithral Ore item itself is tiny compared with the vein. Confirm it reached inventory before walking back to the forge.
Grym fight: use Threat Assessment to control where the boss walks
Grym gains Threat Assessment when attacked, marking the attacker as Prime Target. It then tries to pursue that character. Use a durable or ranged character to take Prime Target, then stand so Grym crosses lava and ends on or near the central anvil. If the Superheated icon falls off, stop spending damage resources and restore lava first.
When Grym is Superheated and on the centre, pulling the forge lever drops the hammer for 12d8 Bludgeoning damage, doubled by its current Bludgeoning vulnerability, and knocks it Prone. The hammer removes Superheated immediately. Hammering while Grym is not Superheated still knocks it Prone but deals no meaningful damage. Magma Mephits can appear during the fight, so leave at least one party member able to clear or control them instead of putting all four characters on lever duty.
The hammer plan only works when Grym is Superheated and positioned on the central anvil; the lava valve and forge lever are two separate jobs.
What should you craft? / Troubleshooting: forge looks stuck or the second craft will not start
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| Item | Key long-term value | Best fit |
|---|---|---|
Adamantine Splint Armour | 18 AC, flat damage reduction, immunity to critical hits, longer Reeling rider | Heavy-armour frontline. |
Adamantine Scale Mail | 16 AC, damage reduction, immunity to critical hits, Reeling | Medium-armour frontline. |
Adamantine Shield | +2 AC, anti-critical, Reeling when melee attackers miss, Shield Blow | Any shield user; unusually easy to keep relevant. |
Adamantine weapons | Ignore matching physical resistance and automatically crit objects | Specific resistance/object-breaking plans; commonly replaced by stronger weapon passives. |
Mould/ore will not insert: verify the actual Mithral Ore item is in an active character inventory and the Mould Chamber is empty.; Grym takes no damage: inspect it. No Superheated means stop attacking and restore lava.; Hammer hit did zero: Grym was not Superheated when the hammer landed.
Platform was raised after crafting: the forge can become awkward/nonfunctional until re-lowered through its platform control; finish both crafts before leaving when possible.; Second craft will not produce: eject/swap the mould if needed, add the second ore, restore the forge to the lowered state, then repeat the normal sequence.; Heavy armour + shield party: Splint + Shield is the safest general-purpose pair.
No heavy-armour user: Scale + Shield spreads defensive value across two characters.; Two frontliners with different armour proficiency: Splint + Scale is clean.; Only craft a weapon if you can name the build or encounter niche that makes its passive more valuable than a second defensive piece.
Treat the hammer as a positioning tool, not a guaranteed one-button kill. The dangerous part is moving Grym through lava without grouping the party where one knockback or lava mistake hits everyone.; Keep one escape/mobility character off the central path. A failed Prime Target setup is recoverable if the entire party is not standing next to Grym.; Do not burn limited burst into Adamantine Skin. The status check matters more than the damage spreadsheet.; Craft decisions are permanent because the ore count is fixed; Honour is a bad place to discover you wanted a shield after spending both pieces.
Honour Mode notes / Common mistakes
Starting the forge with only one Mithral Ore because the second vein was never found.
Assuming the huge ore vein itself goes into the crucible; only the mined item does.
Using the hammer when Superheated has already disappeared.
Standing the party in lava channels when turning the valve.
Crafting two weapons because their names sound exciting, then replacing both while the anti-critical armour would still be useful.
FAQ
How many Adamantine items can you craft? Two in a normal run, because there are two Mithral Ore veins.
Do you have to kill Grym with the forge hammer? No. Bludgeoning damage while Superheated can kill it normally; the hammer is the dungeon mechanic and a strong option.
Why is Grym immune? Adamantine Skin blocks damage until lava applies Superheated.
Can the same mould be used twice? Yes; the second craft may reuse or replace the mould if you have the second ore.; What are the safest crafts? Armour and/or Shield usually have the widest long-term value.