How to Upgrade Tarstones in Mortal Shell 2
To upgrade Tarstones, find the Etching Needles in the Glutted Mire and give them to Franz at the Tarforge in Marrow Keep. Then slot a Tarstone into an equipped weapon or sidearm, kill enemies until its XP bar is full, and return to the Tarforge to pay the upgrade cost.
Etching Needles location
- Enter the Glutted Mire Corrupted Gate in southeast Fainweald.
- Progress far enough to activate the Sunken Village beacon.
- Cross the rope bridge and continue past the Tarblighted Shepherd encounter.
- After meeting Ruk, look before the Magdalena fight for a chest between a tree and a lit torch.
- Take the Etching Needles back to Franz in Marrow Keep to add Tarstone upgrades to the forge menu.
How Tarstone XP works
- Slot it: the Tarstone must be in a weapon or sidearm you currently have equipped.
- Kill enemies: it gains XP from kills; you do not need to trigger its effect.
- Return to Franz: filling the bar makes that stone eligible for its next forge upgrade.
- Repeat: the XP bar resets after an upgrade and begins charging toward the next tier.
Why Tarcore changes the plan
Launch-build reporting shows the first meaningful step at 10,000 XP and 100 Coins, which also awards one Tarcore. Reaching a final effect later requires a much larger commitment, including Tarcore. The practical consequence is more important than memorizing one cost table: level several usable stones before pouring every resource into a single favorite, because those intermediate upgrades build the Tarcore pool needed for a maxed effect.
| Decision | Recommended action | Reason |
|---|---|---|
| New stone | Slot it during normal route clearing | Inventory-only stones earn no XP. |
| First filled bar | Buy the early upgrade when affordable | It improves the stone and begins building Tarcore. |
| Favorite stone | Max only after testing its real combat loop | Final-tier investment is harder to reverse. |
| Fast farming | Use dense routes you can clear safely | Kills, not distance traveled, are the XP engine. |
Should you use Night Mode?
Night Mode increases risk and improves currency rewards, so it can make a familiar farming loop more efficient. It is not required for Tarstone XP. Use it only when the same route remains reliable; dying repeatedly erases the time saved by the higher-reward setting.
Build the rest of the route
If you have not reached the Glutted Mire yet, follow the first-hours route. Pair the final stone choice with the Shell tier listand your actual weapon rather than copying an isolated “best Tarstone” claim.
Verification sources
The unlock loop was cross-checked against this launch-build Tarstone guide, The Outerhaven's Franz/Etching Needles guide, and launch-week player reports. Treat the in-game forge UI as the final authority after balance patches.