Mortal Shell 2: Colossus Stone Location and Obsidian Hammer Effects

The Colossus Stone is the Ability Tarstone that turns the Obsidian Hammer into a crowd-clearing tool. Slot it, spend Resolve, and the hammer goes into the ground instead of into a single enemy, sending shockwaves out through everything standing nearby. It only works on one weapon, so there is no reason to hunt it down unless the hammer is your primary.

Quick answer: The Colossus Stone sits in a stone chest in the Silent Steps, at the far north of the area. Fast travel to the Outskirts of Mammon beacon, run the Road to Absolution to Castigator’s Keep, then follow the snowy cliff path north past the specters and drop to the guarded ledge below.

What the Colossus Stone does on the Obsidian Hammer

The base ability consumes 80 Resolve to drive your weapon into the ground, sending shockwaves rippling through nearby foes. The slam knocks enemies into the air, and the shockwaves travel outward in stages, which is what makes it useful against packed groups rather than single targets. Compatibility is locked to the Obsidian Hammer — the stone will not slot into any other primary weapon.

Upgrades do not change the Resolve cost. They add splash damage first, then widen the blast, then raise the splash damage again.

Tier	Effect
Base ability	Consume 80 Resolve to thrust your weapon into the ground and send shockwaves through nearby foes
First upgrade	Each shockwave deals 30 splash damage
Second upgrade	Each shockwave covers a wider area
Third upgrade	Each shockwave deals 80 splash damage

Note: the Tarstone menu numbers these tiers starting from the base ability, so the “30 splash damage” line may appear as Level 1 or Level 2 depending on how your build labels it. The order of the effects is the same either way.

Colossus Stone location: the route from Outskirts of Mammon

Fast travel to the Outskirts of Mammon beacon. This is the cleanest starting point because the whole run is a single line north with no backtracking.

Leave the beacon and follow the Road to Absolution. You will pass Musca’s Cavern on the way — ignore it and keep pushing along the main path.

Player crossing the ruined stone path along the Road to Absolution with the combat HUD on screen — The Road to Absolution runs north from the Outskirts of Mammon beacon toward Castigator’s Keep. Image: Cold Symmetry

Reach Castigator’s Keep and activate its beacon. Light it before you continue, since the chest run past this point ends in a fight and you do not want to repeat the whole approach.

From the keep, take the snowy cliffside path heading north. The route hugs the cliff edge, and you can run most of it without stopping to fight.

Armored character sprinting along a narrow snow-covered cliff ledge past the keep — The snowy cliff path north of Castigator’s Keep leads to the Silent Steps. Image: Cold Symmetry

Run past the specter enemies in the open snowy stretch. They are scattered and slow to commit, so sprinting through costs less health than clearing them.

Blue spectral enemies drifting across a snowy clearing as the player runs past them — Specters patrol the snowfield on the way to the chest ledge. Image: Cold Symmetry

Drop down to the lower ledge at the north end. A group of Prophet Hammers and Hoodmen guards the stone chest here, and they will pull together, so fight them near the ledge edge rather than in the open.

Player closing in on armored enemies guarding the ledge, with combat HUD and equipment slots visible — Armored guards hold the ledge in front of the Colossus Stone chest. Image: Cold Symmetry

Open the stone chest. The pickup prompt reads NEW TARSTONE ACQUIRED: COLOSSUS STONE, and the stone is added straight to your Tarstones list. The Bone Gate nearby is the one that leads to the Forgotten Tower, which is a useful landmark if you are trying to confirm you are in the right corner of the Silent Steps.

Reaching the chest from the Sisters’ Gate side

If you have already unlocked the Sisters’ Gate beacon, there is a shorter approach that skips the long cliff run. Head out through the stone archway into the red-foliage area, run past the enemy there, and jump off the cliff edge onto the rocky platform below.

From that platform, use the traversal point to launch across the chasm, then work across the stone ledges to a second traversal launch point. That one throws you onto an isolated platform with an altar, and the stone chest sits right there. It is two jumps and almost no combat, which makes it the better option if the beacon is available.

Equipping the Colossus Stone and checking it worked

Open the Tarstones menu and slot the Colossus Stone into one of your two Ability slots. You can carry ten Tarstones total — four on the shell, and two each for Combat, Infusion, and Ability — so the Colossus Stone is competing with one other ability, not with your whole loadout.

To confirm it is live, build Resolve with a few melee hits and trigger the weapon art. The hammer should plant into the ground and release shockwaves outward, and your Resolve bar should drop by 80. If the stone shows as incompatible when you try to equip it, the Obsidian Hammer is not your equipped primary — that is the only requirement the ability enforces.

How to upgrade the Colossus Stone at the Tarforge

Upgrades are gated behind a quest item. Franz needs the Etching Needle before the Tarforge in Marrow Keep will offer Tarstone upgrades at all, so pick it up before you start grinding levels.

Grab the Etching Needle from the bone chest just before the Magdalena, the Lady of the Woods boss fight. When you see Ruk past the bridge, drop through the opening and turn right before the tunnel to find the small side area holding the chest.

Hand the Etching Needle to Franz in Marrow Keep. That unlocks the expanded upgrade options on the Tarforge.

Keep the Colossus Stone equipped and kill enemies. Tarstones only gain experience while slotted, so an unequipped stone will never fill its bar no matter how much you fight.

Once the experience bar is full, return to Franz and pay the Coin cost to push the stone to its next tier. Repeat for each tier you want.

Tarstones menu with the Colossus Stone selected and the 30 splash damage upgrade highlighted — The Tarstones menu showing the Colossus Stone’s first upgrade, which adds 30 splash damage per shockwave. Image: Cold Symmetry

Two upgrades in particular are worth the Coin. The wider blast radius is what makes the slam reliable against loose groups instead of only the enemies standing on top of you, and the jump from 30 to 80 splash damage is what turns it from a knockdown tool into something that actually kills. Until then, treat it as crowd control and lean on the hammer’s normal moveset for damage.