Tarstones are combat gems that give the Harbinger passive effects and modifiers, and each one carries four levels that unlock stronger effects as you raise it. Leveling them is a two-part process. You have to unlock the upgrade option at the Tarforge, then feed each stone enough experience before you can spend Coins to push it up a tier.
Quick answer: Pick up the Etching Needles in the Glutted Mire, hand them to Franz at the Tarforge in Marrow Keep, keep a Tarstone slotted in an equipped weapon or sidearm while you kill enemies, then return to the Tarforge and pay Coins once the stone reaches its XP threshold.
Unlock Tarstone upgrades with the Etching Needles
The Tarforge will not let you touch Tarstones until you bring Franz the Etching Needles. This is a key item, and until it is delivered the upgrade option simply does not appear in the forge menu.
How Tarstones earn XP
Tarstones do not level automatically. Each one has to gather experience before the Tarforge will raise it, and there is one firm rule for how that experience is gained.
A Tarstone only earns XP while it is slotted into an equipped weapon or sidearm and you are killing enemies. You do not have to actively trigger the stone’s ability. It just needs to be equipped when foes die. If a stone is sitting in your inventory unslotted, it gains nothing.
Because XP is tied to kills, dense enemy zones and tough foes are the fastest way to charge a stone. Every level resets the progress, so you start earning XP again toward the next threshold after each upgrade.
Tarstone upgrade costs and Tarcore
Unlike weapons and sidearms, Tarstones cost only Coins to level, so you can keep your Ventrium and other smithing stones for the rest of your gear. Each tier raises both the XP requirement and the Coin cost, and the later tiers also pull in a second currency called Tarcore.
| Upgrade step | XP threshold | Cost | Reward |
|---|---|---|---|
| Level 1 to Level 2 | 10,000 / 10,000 | 100 Coins | Grants 1 Tarcore |
| Reaching max level | 20,000 / 20,000 | 6 Tarcore | Unlocks the stone’s final effect |
The Tarcore economy is the catch. Pushing a stone from level 1 to level 2 gives you a single Tarcore, but maxing a stone out costs six of them. That means you need to level several Tarstones, even ones you do not plan to use, just to bank enough Tarcore to fully upgrade the stones you actually want.
Earning XP is the main bottleneck rather than Coins, unless you are also spending heavily on weapons and other gear. Slaying enemies also drops Coin and Gloom at the same time, so a single farming session pays into all three at once.
Confirm a Tarstone leveled up
Open the Tarstones menu and check the level bar on the stone. When its XP shows a full threshold, such as 10,000 / 10,000, the Tarforge will present an upgrade prompt for that stone. After you pay, the stone’s level ticks up, the next tier’s effect becomes active, and the XP bar resets to begin filling toward the following threshold.
If the upgrade option is missing, the usual reasons are simple. Either the Etching Needles have not been delivered to Franz yet, or the stone has not reached its XP threshold because it was not slotted in an equipped weapon or sidearm while you were fighting.
Farm Tarstone XP faster with Night Mode
Night Mode speeds up XP farming by boosting the Gloom and Coins you earn, at the cost of making enemies deadlier. Since Tarstone XP comes from kills, the same runs that fill your stones also stack up more currency while the mode is active.
You toggle Night Mode by talking to Thestus, an NPC who appears after you light the extinguished lantern on top of Marrow Keep. To light it you need the Gloombound Flame, which is found near the Great Arbiter of Flesh boss at Widow’s Overlook.
Work a stone up to level 2 whenever you can, spread your XP grinding across several Tarstones to bank Tarcore, and the maxed-out effects on your favorite stones will come together without a Coin shortage getting in the way.
