Tarcore is the resource you spend to push Tarstones to their maximum level in Mortal Shell 2, and it is deliberately scarce. There is no chest, drop, or vendor that hands it to you directly. The only way to build a stockpile is to run Tarstone upgrades at the Tarforge, because each upgrade returns Tarcore as a byproduct.
Quick answer: Take Tarstones to the Tarforge in Marrow Keep and upgrade them from level 1 to level 2. Each of those upgrades costs 100 Gold and returns 1 Tarcore. With all 73 Tarstones raised one tier, you can collect up to 73 Tarcore in a single playthrough.
Where Tarcore comes from in Mortal Shell 2
Tarcore is produced when you level up a Tarstone at the Tarforge. The machine sits in Marrow Keep, and Franz, the Tarforge Smith, stands beside it. Once a Tarstone hits its XP threshold, upgrading it drops Tarcore into the central receptacle of the Tarforge, and you collect it from there.
The higher the tier you upgrade, the more Tarcore you get back. A level 1 to level 2 upgrade returns a single Tarcore. A level 2 to level 3 upgrade returns three. That output is the whole supply, so every Tarcore you ever hold started as a Tarstone upgrade.
Unlock Tarstone upgrades with the Etching Needles
You cannot upgrade Tarstones, and therefore cannot earn any Tarcore, until you bring the Etching Needles to Franz. This key item sits in an unguarded chest inside the Glutted Mire, the Corrupted Gate dungeon in the southeast of Fainweald, and you reach it just before the Magdalena, Lady of the Woods boss fight.
Push through the level until you tag the Sunken Village beacon, cross the rope bridge, and defeat the Tarblighted Shepherd. Squeeze through the gap in the wooden boards, pass Ruk, and the chest with the Etching Needles is just beyond that point. Hand the item to Franz, and the Tarforge menu will let you level Tarstones from then on.
Tarstone upgrade costs and Tarcore returns
The two upgrade tiers behave very differently. The first is almost free and pays out. The second forces you to spend Tarcore up front and only refunds part of it.
| Upgrade | Cost | Tarcore returned | Net Tarcore change |
|---|---|---|---|
| Level 1 → Level 2 | 100 Gold | 1 | +1 |
| Level 2 → Level 3 | 150 Gold and 6 Tarcore | 3 | −3 |
Raising a Tarstone to level 3 asks for 6 Tarcore before the process starts, then hands back 3 once it finishes. The real cost of a maxed Tarstone is therefore 3 Tarcore, but you still need the full 6 available up front. That is why banking Tarcore from cheap level 2 upgrades matters so much.
How Tarstones earn XP for upgrades
A Tarstone only gains XP while it is slotted into a weapon or sidearm you have equipped, and it earns that XP when you kill enemies. Sitting in your inventory does nothing. The stone must be active in your loadout during combat.
The thresholds are fixed. A Tarstone reaches its first upgrade point at 10,000 XP, which unlocks the level 1 to level 2 upgrade. It reaches the next point at 20,000 XP, which is where the level 2 to level 3 upgrade becomes available.
Best way to farm Tarcore
There are 73 Tarstones in the game. Because every level 1 to level 2 upgrade adds a Tarcore for almost nothing, cycling all of them through that single tier is the most efficient way to gather the resource. The plan is to keep swapping fresh, unupgraded stones into your loadout, level them, then repeat.
When to spend Tarcore on level 3 Tarstones
Save the maxing step for Tarstones your build actually relies on. Every level 3 upgrade drains 3 Tarcore from your total after the partial refund, so it is a net loss rather than income. Pushing an underwhelming stone to level 3 wastes the Tarcore you farmed from the cheap upgrades.
You will know a Tarcore run worked when the receptacle at the Tarforge holds the new material after an upgrade and your inventory count rises. If an upgrade option is greyed out, the Tarstone has not reached its XP threshold yet, or you are short on the required Gold or Tarcore for that tier.
