How to Upgrade Tarstones in Mortal Shell 2

Upgrading Tarstones in Mortal Shell 2 is one of the best ways to boost your build, but the option to do it is locked behind a key item most players walk straight past. You will not see a Tarstone upgrade option at the Tarforge until you find the Etching Needles and hand them to Franz. Miss that chest and you will spend the whole game running level 1 stones when your build could be doing a lot more. This guide covers exactly where to get the Etching Needles, how the full upgrade process works, what Tarcores are and how to farm them, and the smartest way to spend your upgrade resources. For a deeper look at all four progression currencies in the game, see our Shell Bond and Glimpse guide, and check the Mortal Shell 2 beginner’s guide for everything else you need in your first few hours.

TL;DR – How to Upgrade Tarstones in Mortal Shell 2

• Tarstone upgrades are locked until you find the Etching Needles and give them to Franz at the Tarforge in Marrow Keep.
• The Etching Needles are in a bone chest in the Glutted Mire Corrupted Gate, just past the Tarblighted Shepherd miniboss and right before the Magdalena boss fight.
• To upgrade a Tarstone, you need two things: XP (earned by killing enemies with the Tarstone equipped) and Gold (for the first upgrade) or Tarcores (for the second).
• Level 1 → Level 2: Reach 10,000 XP, then pay 100 Gold at the Tarforge. You get 1 Tarcore back.
• Level 2 → Level 3: Reach 20,000 XP, then spend 6 Tarcores. You get 3 Tarcores back.
• Tarstone XP is never lost on death, only earned while the stone is actively equipped.
• The Tarstone upgrade cap is 4 levels total. The Endless Core key item raises the ceiling for all equipment upgrades near the end of the game.
• To farm Tarcores, upgrade low-value Tarstones you do not plan to use. Each level 1→2 upgrade costs just 100 Gold and gives 1 Tarcore back.

What Are Tarstones in Mortal Shell 2?

Tarstones are equippable stones that slot into your weapons, sidearms, and Shell to add passive effects and modifiers. They can increase damage, improve critical hit chance, apply status effects like Burn or Bleed, add stagger damage, and even trigger new active abilities. They are one of the most flexible parts of your build and they scale significantly with upgrades, so a level 3 Tarstone is far more powerful than the same stone at level 1.

There are 75 Tarstones in total and they come in four types.

• Support: Passive stat boosts such as critical hit chance, stagger damage, or extra damage to specific enemy types.
• Combat: Active damage modifiers like leech, damage over time, or conditional bonuses triggered by specific attack types.
• Infusion: Adds a status effect to your weapon on hit, such as Burn, Bleed, Poison, Frost, or Shock. Infusion Tarstones usually need to be activated with a button press and consume Resolve.
• Ability: Adds a brand-new active move to your weapon or sidearm, changing how you can fight beyond basic attacks.

You can equip up to 10 Tarstones at once: 4 Shell-compatible stones, and 2 each for Combat, Infusion, and Ability slots. Not every Tarstone works with every weapon. Always check compatibility before farming XP on a stone you plan to use with a specific weapon. For help choosing the right stones for your build, see our best Tarstones for beginners guide.

How to Unlock Tarstone Upgrades – The Etching Needles

By default, the Tarstone upgrade option at the Tarforge is completely locked. You will see the Tarforge in Marrow Keep from your very first visit, but the option to upgrade Tarstones will be greyed out until you deliver the Etching Needles to Franz.

The Etching Needles is a key item that unlocks the Tarstone upgrade function at the Tarforge. Once Franz has it, you can interact with the Tarforge to see all your Tarstones and begin upgrading any that have reached their XP threshold. You also receive your first free Tarcore the moment you hand the item to Franz.

Where to Find the Etching Needles

The Etching Needles are found in the Glutted Mire, which is the Corrupted Gate in the southeastern part of Fainweald. This is the swamp biome area and it sits along the natural story path, so you will reach it during normal progression.

Here is the exact route to the chest.

• Progress through the Glutted Mire normally until you cleanse the Sunken Village Beacon inside the dungeon.
• Continue forward until you face the Tarblighted Shepherd miniboss and his enemies. Defeat him to proceed.
• Squeeze through the gap in the wooden boards after the fight.
• In the next area you will find Ruk, an NPC who warns you about the upcoming boss. He is perched near a bridge.
• Cross the rope bridge and look to the right. Jump down the opening and turn right before the tunnel. You will see a small section with a bone chest.
• Open the chest to collect the Etching Needles.

This chest is right before the Magdalena, Lady of the Woods boss fight. Do not skip it. It is very easy to walk past when you are focused on the boss ahead.

After picking up the Etching Needles, fast travel back to Marrow Keep and speak to Franz at the Tarforge. Hand him the Etching Needles and the Tarstone upgrade option will immediately unlock.

Note: There is an alternative. If you kill Franz, the Tarstone upgrade feature also unlocks automatically at the Tarforge. The Tarforge still provides all the same services without him. However, killing Franz for this purpose is not recommended unless you have a specific reason to do so.

How to Upgrade Tarstones at the Tarforge

Once the Etching Needles have been handed to Franz, upgrading Tarstones is a two-step process. First you earn XP on the stone, then you spend resources at the Tarforge to push it to the next level.

Step 1 – Earn Tarstone XP

Tarstones do not level up automatically. They only earn XP while they are actively equipped on your weapon, sidearm, or Shell, and only when you are killing enemies. You do not need to use the Tarstone’s specific ability or effect to gain XP. You just need to have it slotted while you fight.

The good news: Tarstone XP is never lost on death. Unlike Gloom, which drops at your death location and can be lost permanently, any XP your Tarstone earns is kept no matter what happens. This means you can grind XP freely without worrying about dying mid-session.

Tarstones have an XP cap at each level. Once the bar fills, it stops counting. If a Tarstone hits its cap and you have not upgraded it yet, go to the Tarforge immediately. A capped Tarstone is not earning anything until you push it to the next level.

Step 2 – Upgrade at the Tarforge

When a Tarstone’s XP bar is full, interact with the Tarforge in Marrow Keep and select the Tarstone upgrade option. You will see all your Tarstones and which ones are ready to be upgraded. Select the stone and spend the required resources to level it up.

Here are the upgrade costs and XP requirements for each level.

• Level 1 to Level 2: Requires 10,000 XP and costs 100 Gold. You receive 1 Tarcore as a byproduct.
• Level 2 to Level 3: Requires 20,000 XP and costs 6 Tarcores. You receive 3 Tarcores back after the upgrade completes.
• Level 3 to Level 4: Requires additional XP and further resources. The Endless Core key item (see below) is needed to push equipment to its maximum tier.

After upgrading, the Tarstone immediately becomes more powerful and its XP bar resets. Equip it again and keep killing enemies to fill the bar for the next tier.

What Are Tarcores and How to Get Them

Tarcores are the material required to push Tarstones past level 2. They are not found anywhere in the world. The only way to get Tarcores is by upgrading Tarstones at the Tarforge. Every time you upgrade a Tarstone, the Tarforge produces Tarcores as a byproduct. Collect them from the central receptacle of the Tarforge after each upgrade.

• Upgrading a Tarstone from level 1 to level 2 gives you 1 Tarcore.
• Upgrading a Tarstone from level 2 to level 3 costs 6 Tarcores and gives you 3 Tarcores back.

This means the net cost of a level 2 to level 3 upgrade is 3 Tarcores. But you still need 6 upfront before the Tarforge will let you start the process. That forces you to stockpile by upgrading multiple Tarstones to level 2 first.

How to Farm Tarcores Fast

Since you need 6 Tarcores to push one Tarstone from level 2 to level 3, and each level 1 to level 2 upgrade only gives 1 Tarcore, you need to upgrade at least 6 different Tarstones to level 2 before you can max out a single priority stone. The smartest way to do this is to use stones you do not plan to keep as a Tarcore farm.

Here is the most efficient method.

• Pick up every Tarstone you find, even ones that do not suit your build. Every Tarstone is a potential Tarcore source.
• Equip low-value Tarstones in your slots alongside your main stones. They earn XP passively just by being slotted during normal play.
• Upgrade every stone to level 2 as soon as it hits 10,000 XP. Each one costs only 100 Gold and returns 1 Tarcore. Gold is easy to earn in comparison.
• Bank those Tarcores until you have at least 6, then spend them on the Tarstone you actually want at level 3.
• When you upgrade a priority stone from level 2 to level 3 you get 3 Tarcores back. Reinvest those into the next stone you want maxed.

This loop means even weak Tarstones have value as Tarcore generators. Never vendor or ignore a Tarstone just because it does not fit your current build. It is free Tarcore waiting to happen. For the best Tarstones to prioritise upgrading first, see our best Tarstones for beginners guide.

How to Level Up Tarstones Fast

XP is the main bottleneck for Tarstone upgrades, not Gold or Tarcores. The faster you earn XP on your stones, the faster you can push them to higher levels. Here are the best ways to speed it up.

• Keep Tarstones equipped at all times. XP only counts when a stone is slotted. If you are exploring or grinding Gloom, make sure your Tarstones are in their slots even if you are not actively using their effects.
• Fight stronger enemies. Tougher enemies give more XP per kill than weak ones. Clearing boss arenas, dense enemy zones, and late-game regions accelerates XP income significantly compared to farming basic enemies near the start of the world.
• Use Night Mode. Enabling Night Mode by talking to Thestus in Marrow Keep increases the amount of Gloom, Gold, and Tarstone XP you earn per kill while making enemies more dangerous. It is the fastest way to farm XP on your Tarstones if you can handle the increased difficulty. You need the Gloombound Flame to unlock it, which is found near the Great Arbiter of Flesh boss close to the Widow’s Overlook Beacon. Once you have it, light the lantern on top of Marrow Keep to make Thestus appear.
• Equip multiple Tarstones in parallel. You have up to 10 slots. Filling all of them means up to 10 stones earning XP at the same time from every kill.
• Do not swap stones mid-grind. Stick with the same loadout during a farming session so each stone accumulates XP cleanly without interruption.
• Upgrade as soon as XP caps. The moment a Tarstone hits its XP limit, visit the Tarforge and upgrade it. Every kill after the cap is wasted until you do. Keeping your stones from hitting the wall means no dead XP.

If you are farming enemies for Tarstone XP, you will also earn Gloom at the same time. Make use of this by doing your XP farming in areas that double as good Gloom spots. See our fast Gloom farming guide for the best zones to combine both goals in one run.

All Tarforge Unlock Items – Full List

The Tarforge in Marrow Keep starts with limited functions. Five key items unlock its full capabilities. Here is every one of them and what each unlocks.

• Muradean Actuator – Unlocks primary weapon upgrades at the Tarforge. Found in a chest inside the Village Outskirts Beacon during the prologue. This is almost impossible to miss as it sits directly on the critical story path.
• Obsidian Lathe – Unlocks sidearm upgrades. Found in the Martyr’s Tomb dungeon, due south of the Widow’s Overlook Beacon in Fainweald. It is near the grave where you unlock the Tiel Shell.
• Etching Needles – Unlocks Tarstone upgrades and Tarcore collection. Found in a bone chest in the Glutted Mire Corrupted Gate, just past the Tarblighted Shepherd before the Magdalena boss fight (as described above).
• Foundry Stone – Unlocks weapon smelting, which lets you strip upgrade materials from a weapon and recover the stones used on it. Found in a chest near the Outskirts of Mammon Beacon. Watch out, a large group of knights and soldiers guards this chest.
• Endless Core – Raises the upgrade ceiling for all equipment including Tarstones, allowing upgrades beyond the standard cap. Found in the Hidden Nave Beacon inside the Unfound Path dungeon, near the end of the campaign just before the final boss. Clear the corrupted tendrils in the zone to unlock this Beacon.

None of these items are missable. You can collect all five in free roam after the final boss, before starting New Game Plus. However, getting the Etching Needles and Endless Core early gives your Tarstones far more time to grow during your run. Unlock them as soon as you can. For more on the Tarforge and weapon upgrades see our full Tarforge guide.

Tarstone Upgrade Tips and Mistakes to Avoid

• Do not ignore Tarstones you dislike. Every Tarstone you own is a Tarcore source. Upgrading a stone you do not want to use from level 1 to level 2 still costs only 100 Gold and pays you 1 Tarcore. Those Tarcores add up fast and let you max the stones you actually care about.
• Do not wait too long to upgrade. A Tarstone at its XP cap earns nothing. Visit the Tarforge regularly during your run so your stones never sit idle at full XP.
• Build around your Shell first. Tarstones amplify a playstyle. They work best when they match what your Shell already does well. Critical-damage stones suit Tiel. Stagger and strength stones suit Gragu and Eredrim. Status infusions work well on ranged-heavy builds. See our best Shells tier list for which Shells pair best with which stone types.
• Match Tarstones to your weapon. Not every stone is compatible with every weapon. Check the compatibility icons before farming XP on a stone you intend to use with a specific loadout. See all weapon options in our all weapon and sidearm locations guide.
• Unlock the Endless Core before the final boss if you want to push Tarstones to max level in your first run. It is found near the end of the game but before the point of no return into NG+.
• Use Night Mode for the fastest XP. It is risky, but the XP and Gold income jump makes it the best farming method once you are comfortable with the game’s combat.
• Upgrade Seals too. The best Seals guide covers which defensive options work alongside high-investment Tarstone builds so your offense and defense grow together.

Frequently Asked Questions

Bottom Line

Upgrading Tarstones in Mortal Shell 2 comes down to three things: find the Etching Needles early, keep your Tarstones equipped at all times so they never stop earning XP, and farm Tarcores by pushing low-value stones to level 2 before spending them on the stones that matter. The system rewards players who engage with it consistently. A fully upgraded Tarstone on a well-matched weapon is a meaningful power spike, and the players who get there early have a noticeably smoother time in boss fights and late-game content.