Mortal Shell 2: How to Get the Endless Core and Lift the Upgrade Cap

Weapon enhancement in Mortal Shell 2 hits a wall late in the game. Franz’s Tarforge will happily take your Thoracium until a weapon or sidearm tops out, and then the option to keep going simply is not there. The Endless Core is the component that removes that ceiling, and it sits at the far end of one of the game’s last major dungeons.

Quick answer: Deliver 168 Ova at Marrow Keep to open the Unfound Path, defeat Malborn Offspring, The Monolith, and Orrem, cleanse all three bone structures, then loot the chest inside The Hidden Nave.

What the Endless Core does at the Tarforge

The Endless Core is an upgrade material, but you never spend it on a weapon. You feed it to the Tarforge once, and it permanently removes the level cap on both weapons and sidearms. After that, enhancement continues into the final material tier instead of stopping.

The device gives off an eager hum. It enables endless labor, yet toward what goal? Finality can bring freedom; infinity continues onward.

Here is where the Core fits into the full enhancement ladder used by primary weapons and upgradeable sidearms:

Levels	Material	Gate
+1 to +5	Ventrium	Muredean Actuator
+6 to +10	Laterite	—
+11 to +15	Dorsalite	—
+16 to +20	Thoracium	—
+21 and up	Ossinite	Endless Core

Ossinite is the final tier material, and it only becomes usable once the Core is installed. Treat every piece as scarce — it turns up as placed loot on late routes such as the area around Ossinite Falls Beacon in Withered Shoals rather than from a repeatable farm.

Item Overview — The Endless Core item card, the single component that pushes weapons and sidearms past their normal ceiling. Shown at 00:10 in Empalador 8500’s video.

The other Tarforge unlocks are not interchangeable. Muredean Actuator opens weapon enhancement, Obsidian Lathe opens sidearms, Etching Needles opens Temper Tarstones, and Foundry Stone opens Smelt Equipment. None of them lift the level cap.

Requirements before the Unfound Path opens

The Core sits in an underground area that is sealed until you have taken the main campaign most of the way to its end. Check these off before you go looking for it:

Clear the main gates and their bosses, and cleanse the corrupted beacons along the way.
Collect and deliver 168 Ova at Marrow Keep.
Interact with the Gloom Siphon at Marrow Keep to open the descending passage.
Have Thoracium and coin banked, since you will want to spend the cap increase immediately.

Once the Siphon accepts the delivery, a stairway opens beneath Marrow Keep. Drop down the shaft from the Marrow Keep beacon and you land in a flooded cavern — that is the entrance to the Unfound Path.

Clear the three curse bosses in the Unfound Path

Three curses keep The Hidden Nave sealed. Each one is tied to a boss and a fleshy bone structure somewhere past that boss’s arena. Kill the boss, walk to the structure, interact with it, and a cutscene cleanses that curse and teleports you back to the Chamber of the Forsaken — which makes that beacon your hub for all three runs.

Boss	Nearest beacon	Reward
Malborn Offspring	Faithful’s Shelter	Offspring Trophy
The Monolith	Obsidian Vault	Monolith Fragment
Orrem	Bridge of Procession	Orrem’s Head

Revitalize every beacon you pass. The fast travel list fills out quickly down here, and the teleport back to Chamber of the Forsaken after each cleanse is only useful if the next branch’s beacon is already lit.

Location Selection Menu — The fast travel list after the Unfound Path beacons are lit, with The Hidden Nave at the top. Shown at 01:16 in Empalador 8500’s video.

First curse: Malborn Offspring

From the landing point in the watery cavern, follow the path forward and revitalize the Chamber of the Forsaken beacon. This is the point you will be returned to after every cleanse, so light it first.

Push through the fogged cavern corridors to reach Receiving Hall, then continue up the stone stairs and through the enemy-filled halls beyond it to reach Faithful’s Shelter.

Run from Faithful’s Shelter to the circular arena and kill Malborn Offspring for the Offspring Trophy. Then head to the large bone structure past the arena and interact with it to lift the first curse.

Second curse: The Monolith

From Chamber of the Forsaken, take the opposite branch, fight through the snake-like enemy guarding it, and light the Brother’s Court beacon.

Follow the platforming route along the red fleshy walls and stone ledges until you reach the Obsidian Vault beacon. This stretch has real fall damage, so take the jumps slowly.

Finding Obsidian Vault — The ledge route through the red flesh walls that leads to the Obsidian Vault beacon. Shown at 04:48 in Shark R’s video.

Continue from Obsidian Vault to the stone arena and defeat The Monolith to claim the Monolith Fragment. Interact with the second bone structure nearby to cleanse the second curse.

Third curse: Orrem

Back at Chamber of the Forsaken, take the cliffside route across the stone bridges and light the Bridge of Procession beacon.

Fight Orrem, the giant skeletal worm, and take Orrem’s Head. The arena has an elevator on the far side.

Third Boss: Orrem — Orrem, the skeletal worm guarding the third curse, drops Orrem's Head on death. Shown at 07:52 in Shark R’s video.

Ride the elevator up and light the Empty Cradle beacon, then push past the spider-like enemies to the third bone structure and interact with it. That is the final curse lifted.

The Hidden Nave torch puzzle and the Endless Core chest

With all three curses gone, the central tree beacon, The Hidden Nave, is cleansed and appears in your fast travel list. Everything past it is pitch dark and thick with fog, and the one campfire you find at the entrance has no torch on it. The torch is on the other side of the fog.

Travel to The Hidden Nave, cleanse the beacon if it is not already, and walk into the cavern corridor behind it. The first campfire is empty — ignore it for now.

Entering the Misty Cavern — Past the cleansed Hidden Nave beacon, the corridor turns dark and fogbound. Shown at 01:19 in Sofa Supastar Gaming’s video.

Run straight through the fog wall to reach a second campfire. There is an engraving nearby mentioning Prophet Smerte and the chamber beneath Marrow Keep. Look on the ground by the fire and use the Take Torch prompt to grab the makeshift torch.

Carry the lit torch back through the fog. The mist no longer blinds you, and the pillared chambers ahead open up. Along the way you can harvest the Futilium nodes scattered through the crystal caverns.

Navigating the Fog with Torch — With the torch equipped, the fogged path resolves into the pillared chambers below. Shown at 02:02 in Sofa Supastar Gaming’s video.

Drop down the final ledges until you reach a pale stone chest sitting beside glowing braziers and mineral deposits. Open it. The New Item Acquired: Endless Core prompt confirms the pickup.

Install the Endless Core at the Tarforge and confirm it worked

Fast travel back to Marrow Keep and walk up to the Tarforge machine. This one is not a Franz conversation — you install it through the forge menu yourself. A new option, Install Endless Core, sits alongside Enhance Weapons, Enhance Sidearms, Smelt Equipment, and Temper Tarstones. Select it.

You know it worked when the Install Endless Core entry disappears from the menu and Enhance Weapons lets you keep advancing a maxed weapon instead of greying the next level out. Open Enhance Weapons or Enhance Sidearms, pick the weapon you had parked at its old ceiling, and the next upgrade step should now display an Ossinite and coin cost rather than nothing at all.

If a weapon still refuses to advance after the install, check that you are in the right service — sidearms use Enhance Sidearms, not Enhance Weapons — and that you are actually carrying the next tier’s material and enough coin.

Because the Core lifts the cap on your whole arsenal rather than a single item, the real constraint afterwards is material supply. Pick the one weapon and one sidearm you intend to finish the game with before you start burning Ossinite, since the late tiers are placed loot and late-route rewards rather than something you can grind back.