Mortal Shell 2: Ironpiercer’s Stone Tarstone Location and How to Use

The Ironpiercer’s Stone is one of the few Combat Tarstones in Mortal Shell 2 that changes how your Sidearm behaves rather than how much damage it does. Instead of stopping at the first body it hits, a projectile keeps travelling through a line of enemies, which turns corridors and choke points into free damage.

Quick answer: Cleanse the Nochtean Gate beacon to open the Corrupted Gate, cleanse the Slumwater Drain beacon on the other side, then work through the Central Sewers and the poison tunnels until you reach a broken bridge. Jump the gap and loot the stone from the altar at the end.

Ironpiercer’s Stone effects and pierce limits

This is a Combat-type Tarstone and it slots into a Sidearm only. The base effect is simple, with projectiles punching through enemies rather than stopping on impact. What upgrading changes is the number of bodies a single shot can pass through before it dies.

Level	Effect
Level 1	Projectiles pierce up to 3 foes before stopping
Level 2	Projectiles pierce up to 4 foes before stopping
Level 3	Projectiles pierce up to 5 foes before stopping

It will not attach to every ranged weapon. The stone is limited to the Sidearms below, so check what you have equipped before you plan a build around it.

Compatible Sidearms
Ballistazooka
Caged Hystrix
Forgotten Crossbow
Naylshotte
Salvaged Trebuchaxe

The value is highest when enemies stack up behind each other, which happens constantly in tunnels, doorways, and on bridges. Line the shot up along the group instead of firing at whoever is closest.

Opening the Corrupted Gate and reaching Slumwater Drain

You cannot walk into the dungeon that holds the stone straight away. The path runs through a Corrupted Gate, and that gate only opens once the beacon tied to it has been cleansed.

Travel to the Nochtean Gate beacon and cleanse it. This is the trigger that clears the corruption blocking the Corrupted Gate nearby, so nothing else in the route works until it is done.

Armored Harbinger with sword drawn moving along a torch-lit rocky path toward the gate — Heading along the torch-lit path toward the gate after cleansing the beacon. Image: Cold Symmetry

Run through the now-open Corrupted Gate. The area on the other side is darker and more enclosed than the approach, so keep your Sidearm loaded for the ranged enemies waiting inside.

Player character walking through a dark cavern passage past the opened Corrupted Gate — The dark cavern stretch immediately past the Corrupted Gate. Image: Cold Symmetry

Follow the passage until you get the Beacon Found prompt for Slumwater Drain, then interact with it and pick Cleanse Beacon. That gives you a checkpoint right outside the dungeon, which matters because the tunnels ahead drain health steadily.

Central Sewers route to the Ironpiercer’s Stone altar

Inside, the dungeon opens into the Central Sewers. The layout hides a lot behind breakable surfaces, and the second half is flooded with poison, so treat the two halves differently.

Work through the Central Sewers and hit the wooden barriers and suspicious stone walls as you go. Several side rooms are sealed behind them, and one of them holds the Sheephead Totem.

Harbinger standing at the edge of a cavern lit from below by molten light inside the sewers — One of the open cavern drops inside the Central Sewers. Image: Cold Symmetry

Push into the poison-filled tunnels. Enemies here come in small clusters, and fighting them while standing in the poison is what kills most runs, so pull them back into clean ground where you can.

Player approaching a red-flamed torch mounted on the rock wall of a narrow tunnel — Red-flamed torches mark the narrow tunnel stretch past the sewers. Image: Cold Symmetry

Keep going until the tunnel ends at a bridge that has collapsed in the middle. Back up, sprint, and make a running jump across the gap. A standing jump will not clear it.

Loot the altar on the far side to pick up the Ironpiercer’s Stone. This is the end of that branch, so there is nothing to miss further along.

Optional pickups on the same run

There is a Synaptic Vessel tucked away in the same dungeon, and it is easy to walk past. A wooden bridge above the route can be shot down with your Sidearm, dropping it into place as a walkway. Cross it, grab the Vessel, and then rejoin the main path.

Player climbing a dark wooden staircase with sword drawn on the way to the upper walkway — Climbing the wooden structure on the way to the Synaptic Vessel detour. Image: Cold Symmetry

The Sheephead Totem sits behind one of the broken walls earlier in the Central Sewers. Neither pickup is required to reach the Tarstone, but both are on the same trip.

How to equip the Ironpiercer’s Stone and confirm it is active

Picking the stone up does nothing on its own. Open the Tarstones menu, select a Combat slot, and infuse it into a compatible Sidearm. You have two Combat slots in total, so it competes with the other Sidearm-based Combat stones you are carrying.

You will know it worked from the item card, which reads Projectiles pierce through enemies along with the current pierce cap. In combat, the confirmation is visual. Fire into two or more enemies standing in a line and the shot should register on the ones behind the first.

Note: if the effect appears to do nothing, check that the stone is actually slotted into a compatible Sidearm rather than sitting in your inventory. It will not attach to your primary Weapon or shell.

Raising the pierce cap at the Tarforge

Upgrades run through Franz at the Tarforge in Marrow Keep, but the option is locked until you hand him the Etching Needle. That quest item sits in a bone chest just before the fight with Magdalena, the Lady of the Woods. When you spot Ruk past the bridge, turn right and check the small alcove.

After Franz has it, the stone still needs experience of its own. Keep it equipped and kill enemies until the XP bar fills, then return to the Tarforge and pay Coin to move it to the next level. Each level adds one more enemy to the pierce chain, topping out at five.

At Level 3, a single well-aimed shot from something like the Ballistazooka or the Forgotten Crossbow can clear a whole packed hallway, which is exactly the situation the Slumwater Drain tunnels keep throwing at you on the way back out.