Mortal Shell II tarstone upgrade: Step-by-Step Guide - Guide

Mortal Shell II tarstone upgrade: Step-by-Step Guide

Learn how to unlock Mortal Shell II tarstone upgrades, find the Etching Needle, prepare Tarforge materials, and choose compatible effects.

2026-08-23
Mortal Shell II Wiki Team
Quick Guide
  • Mortal Shell II tarstone upgrade requires the Etching Needle and access to Franz’s Tarforge.
  • Etching Needle location is near the route leading to the Magdalena, the Lady of the Woods encounter.
  • Level 2 upgrades require coins and sufficient Tarstone experience before the option becomes available.
  • Tarstone compatibility matters because each effect can only be equipped to supported equipment.
  • Best preparation is to identify your target effect before spending coins or changing your build.

Mortal Shell II tarstone upgrade basics

The Mortal Shell II tarstone upgrade system expands the passive effects and action modifications available through equipment infusion. Tarstones can influence damage, attacks, critical chance, and interactions that use Resolve. They are not universal attachments, so the equipment slot and compatibility rules should be checked before committing resources.

The upgrade path is tied to the Tarforge in the Marrow Keep and to Franz, the character who handles the required progression item. The first important objective is therefore not spending coins; it is locating the Etching Needle and delivering it to Franz.

Passive Effects

Improve selected combat properties such as damage, critical chance, or resource-related interactions.

Action Changes

Modify an attack or movement pattern connected to the Harbinger or an equipped shell.

Equipment Limits

Tarstones can only be placed into compatible equipment, so verify the target before upgrading.

Build Planning

Choose the equipment you expect to use for several encounters before upgrading a Tarstone. Compatibility is just as important as the effect itself.

What upgrades change

Tarstones occupy a specialized role in equipment progression. Some focus on abilities, while others affect combat performance or infusion behavior. This makes them useful for refining an existing setup rather than replacing the fundamentals of a shell or weapon.

Upgrade considerationWhat to checkWhy it matters
Effect typeAbility, combat, infusion, or otherIdentifies the kind of gameplay interaction being modified
Equipment compatibilityWhether the target accepts the TarstonePrevents wasted preparation on an unsupported item
Upgrade levelWhether Level 2 is unlockedHigher options require additional progression
Resource requirementCoins and Tarstone experienceDetermines when the upgrade can be purchased
Resolve interactionWhether the effect uses ResolveHelps align the Tarstone with resource-focused builds

The available information confirms a Level 2 upgrade path, but it does not establish a universal coin price or a single experience value for every Tarstone. Treat the resource requirement as a progression gate rather than a fixed cost.

How to find the Etching Needle

The Etching Needle is the key item needed to expand Tarstone upgrade options. Its location is connected to the area immediately before the Magdalena, the Lady of the Woods boss fight. The route is easy to overlook because the chest is placed away from the most direct path.

After crossing the bridge and encountering Ruk, turn right instead of continuing directly toward the boss route. Look for a smaller side section containing a bone chest. Loot the chest to obtain the Etching Needle, then take it to Franz in the Marrow Keep.

Route markerActionResult
Bridge areaCross the bridge and locate RukConfirms the correct route landmark
Ruk encounterTurn right after passing RukLeads away from the direct boss approach
Side sectionSearch the smaller areaReveals the bone chest
Bone chestOpen and loot itObtains the Etching Needle
Marrow KeepReturn to FranzExpands Tarforge upgrade options
Do Not Rush the Boss Route

If you continue straight after the bridge, you can pass the side section containing the bone chest. Search near Ruk before entering the Magdalena encounter.

Etching Needle retrieval steps

1

Reach the bridge landmark

Progress through the area until you cross the bridge and see Ruk. This encounter is the most reliable navigation reference for the item’s location.

2

Turn right after Ruk

Move into the smaller side section on the right rather than following the direct route toward Magdalena, the Lady of the Woods.

3

Open the bone chest

Search the side section for the bone chest and loot it. The chest contains the Etching Needle required for Tarforge expansion.

4

Return to Franz

Bring the Etching Needle to Franz at the Tarforge in the Marrow Keep. This unlocks additional Tarstone upgrade options.

The item is associated with Tarforge progression, not with a random drop table or a repeatable farming activity. Once the chest has been found, focus on returning to the smith and reviewing the newly available upgrade options.

Tarforge upgrade process

Once Franz has received the Etching Needle, the Tarforge can offer expanded Tarstone upgrade options. The Level 2 path still has two requirements: coins must be spent, and the Tarstone must have enough experience. Unlocking the interface does not automatically make every upgrade immediately purchasable.

Use the Tarforge as a planning point. Review the effect, confirm the compatible equipment, and then check whether the Tarstone has met its experience requirement. This order reduces the chance of investing in an effect that does not fit the equipment currently used by your Harbinger or shell.

Efficient Upgrade Order

First unlock the Tarforge option, then confirm Tarstone experience, then verify equipment compatibility, and only afterward spend coins.

Upgrade phaseRequirementRecommended action
UnlockGive the Etching Needle to FranzExpand the Tarforge’s available options
PreparationBuild Tarstone experienceUse the Tarstone during normal progression when appropriate
PurchaseSpend coins for Level 2Confirm the effect is suitable before paying
Loadout checkCompatible equipmentApply the Tarstone only where supported
Combat testObserve the changed effectCheck whether the upgrade fits the shell and weapon pattern

A practical upgrade workflow

  1. Identify the target effect. Decide whether you want damage, attack modification, critical chance, or a Resolve-related interaction.
  2. Check the Tarstone category. Category helps narrow the role, but the equipment compatibility rule remains decisive.
  3. Build experience first. A Level 2 option may remain unavailable until the Tarstone has gained enough experience.
  4. Reserve coins. Avoid spending your currency before confirming the intended equipment and effect.
  5. Test the result. Use a familiar encounter to compare the upgraded behavior with your previous setup.

The most reliable approach is to upgrade Tarstones that support a clear combat plan. For example, an effect that modifies an action should be evaluated alongside the shell and equipment that perform that action. A damage-focused effect should likewise be considered in the context of the attack pattern you use most often.

Tarstone categories and build roles

The known Tarstone list is divided into four broad groups: Ability Tarstones, Combat Starstones, Infusion Tarstones, and Other Tarstones. The category names provide a useful starting point when organizing a build, but they should not be treated as a complete ranking system. The strongest choice depends on equipment compatibility and the interaction your build needs.

CategoryKnown entriesGeneral role
Ability TarstonesAcolyte’s Stone, Barrage StoneModifies or supports ability-focused interactions
Combat StarstonesBlackblood Stone, Bulwark StoneSupports direct combat performance
Infusion TarstonesAccursed Stone, Arbiter’s Prize, Auspicious Stone, Berserker’s StoneAdds equipment infusion effects
Other TarstonesTyrant’s Stone, Unstable Stone, Pulse Stone, Sapper’s StoneCovers additional specialized interactions

Acolyte’s Stone

Listed under Ability Tarstones. Consider it when your setup centers on ability-based effects.

Barrage Stone

Also listed under Ability Tarstones. Review the supported equipment before selecting it.

Bulwark Stone

Listed under Combat Starstones. It may suit a defensive or stability-focused setup when compatible.

Berserker’s Stone

Listed under Infusion Tarstones. Compare its role with the attack pattern of your chosen equipment.

Avoid Blind Rankings

The available Tarstone information identifies categories and names, but does not provide enough confirmed data for a universal best-to-worst ranking.

Choosing a Tarstone for your setup

Use the following priority order:

  • Compatibility first: An attractive effect is unusable if the equipment does not support it.
  • Combat purpose second: Decide whether the build needs damage, defense, action changes, critical chance, or Resolve utility.
  • Resource cost third: Confirm that the Tarstone has enough experience and that the coin cost fits your current progression.
  • Testing last: Evaluate the upgraded effect in a familiar fight instead of judging it only from its name.

Tarstones are best understood as build modifiers. They can sharpen a playstyle, but they do not remove the need to manage positioning, shell strengths, attack timing, or Resolve. A carefully matched effect usually provides more value than a randomly upgraded item with a more appealing label.

Pre-upgrade checklist

Before Spending Coins:

  • Obtain the Etching Needle from the bone chest near the Magdalena route
  • Deliver the Etching Needle to Franz at the Marrow Keep Tarforge
  • Confirm the Tarstone has enough experience for the intended level
  • Verify that the target equipment is compatible
  • Choose an effect that supports your shell and combat plan

Upgrade mistakes to avoid

The Tarforge system rewards preparation. The most common mistake is assuming that finding the Etching Needle immediately completes the entire process. The item expands the available options, while Level 2 still depends on Tarstone experience and coins.

Another mistake is treating every Tarstone as interchangeable. The equipment compatibility rule means that an effect must be evaluated together with the item receiving it. If your build changes after the upgrade, the Tarstone may no longer be the best fit for the equipment currently in use.

MistakeWhy it causes problemsBetter approach
Skipping the side area near RukThe bone chest can be missed on the direct routeTurn right after the bridge and search carefully
Spending coins immediatelyThe effect may not suit your intended equipmentConfirm compatibility and build purpose first
Ignoring Tarstone experienceLevel 2 may remain unavailableUse the Tarstone during progression and revisit the Tarforge
Choosing by name aloneNames do not establish universal performanceMatch the effect to your shell, weapon, and Resolve use
Upgrading without testingThe changed action may feel different in combatTest in a familiar encounter before changing the whole build
Editor’s Recommendation

Keep one clear upgrade goal at a time. Improving a Tarstone for a known equipment setup is easier to evaluate than upgrading several unrelated effects together.

Final preparation route

Return to the Marrow Keep after obtaining the Etching Needle and speak with Franz. Review the Tarforge options, select the Tarstone you intend to develop, and check its current experience. If Level 2 is unavailable, continue progressing with that Tarstone rather than assuming the interface is broken.

Before confirming the purchase, compare the effect with your current shell and equipment. Pay special attention to modifications involving attacks, movement, critical chance, damage, or Resolve. These effects can change how an encounter should be approached, so the upgrade should support a deliberate playstyle.

For additional item details and the current Tarstone list, consult the Tarstones reference page.

Mortal Shell II tarstone upgrade FAQ

Q: How do I unlock Tarstone upgrades in Mortal Shell II?

Find the Etching Needle in the bone chest near the route to Magdalena, the Lady of the Woods, then give it to Franz at the Tarforge in the Marrow Keep.

Q: Where is the Etching Needle located?

After crossing the bridge and passing Ruk, turn right into the smaller side section. Search there for a bone chest containing the Etching Needle.

Q: What does the Level 2 Tarstone upgrade require?

The Level 2 option requires coins and enough Tarstone experience. Unlocking the Tarforge expansion does not remove those additional requirements.

Q: Can every Tarstone be equipped on every item?

No. Tarstones can only be equipped to compatible equipment. Check the supported item before spending coins or changing your build.

Keep Requirements Separate

The Etching Needle unlocks expanded Tarforge options, while coins and Tarstone experience govern the Level 2 upgrade itself.

The safest upgrade plan is straightforward: locate the Etching Needle, return to Franz, develop the Tarstone through normal progression, and confirm compatibility before purchasing Level 2. This keeps the resource investment aligned with the equipment and combat style you actually use.