Mortal Shell 2: Crumbling Tunnel Dungeon Location

Crumbling Tunnel is a small dungeon in the Blackridge Cliffs region of Mortal Shell 2. It hides in a cave beside the Shattered Beacon, and the map stays blank on it until you walk through the foggy doorway.

Quick answer: From the Blackridge Pass beacon, travel northeast toward the Shattered Beacon, then enter the cave on the eastern side of that path.

Crumbling Tunnel location near the Shattered Beacon

Blackridge Cliffs sits in central Fainweald, north of Widow’s Overlook. The cleanest pin for Crumbling Tunnel is not the cliff line itself. It is the pair of nearby landmarks, Blackridge Pass and the Shattered Beacon.

Open the map at Blackridge Pass and look northeast. The player marker should sit close to the Shattered Beacon dungeon, around map coordinates 12916, 20193. Crumbling Tunnel is the cave directly east of that Shattered Beacon entrance, across from the structure where you recover Proxima’s shell.

World map with fast-travel beacons and the player marker in Blackridge Cliffs — The map in Blackridge Cliffs, with the player marker northeast of Blackridge Pass. Image credit: Cold Symmetry / via @PazarGamingGuides

Landmark	Relation to the cave
Blackridge Pass beacon	Southwest of the dungeon. Use this as the starting point.
Shattered Beacon	Directly across from the cave, just to the west. Proxima is inside.
Cave mouth	On the eastern side of the path, to the right of the Shattered Beacon.

Path from the Blackridge Pass beacon

You do not need a key. The door is a cave in the open cliffs. Reach Blackridge Pass first, then close the last stretch on foot.

Travel to the Blackridge Pass beacon in Blackridge Cliffs and rest or cleanse there so you have a nearby return point.

Leave the beacon and move northeast toward the Shattered Beacon. Stay on the path that runs past the area where an Infested Stalker guards that beacon.

Clear or slip past the large enemy on that stretch. The route east toward the cave is short once the path is open.

Armored figure swinging a large axe at a towering skeletal foe in Blackridge Cliffs — A fight in Blackridge Cliffs against a towering skeletal enemy on the approach. Image credit: Cold Symmetry / via @PazarGamingGuides

At the Shattered Beacon, turn east and look along the right-hand side of the path. The dungeon entrance is the cave mouth there, not the beacon interior where Proxima lies.

Walk through the foggy doorway. Entering the cave is what unlocks Crumbling Tunnel as a named dungeon on your map.

Note: Coward’s Retreat is a different cave along a rocky wall just east of Blackridge Pass. If you ducked into a hole immediately after leaving that beacon, you are in the wrong dungeon.

Confirm you unlocked Crumbling Tunnel

The game marks a dungeon when you first pass its foggy doorway. Inside the cave, open the map. The label should read Crumbling Tunnel, with a dungeon icon on the marker. The local map may also show as unavailable for that interior, which is expected.

You can flag the icon yourself after the visit. Move the cursor over Crumbling Tunnel and use the Mark Complete option so the symbol changes. The game does not flip that icon on its own.

Map cursor over the Crumbling Tunnel dungeon icon with a Mark Complete prompt — The map cursor on Crumbling Tunnel, with the Mark Complete option visible. Image credit: Cold Symmetry / via @PazarGamingGuides

If the map still has no Crumbling Tunnel label, you have not crossed that fog yet. Back out and check that you are east of the Shattered Beacon rather than in Coward’s Retreat.

Crumbling Tunnel contents and collapse

Past the fog, a wooden lever drops a platform lift into a mine shaft. The tunnel below is short. A green statue on the right holds Ventrium, and a fallen rock further in hides Laterite. The reason to come here is the large white bone tablet at the far end, under explosive pots. That tablet is the map to the Triarch Repeater, Proxima’s sidearm, which you collect later.

Find	Where it sits
Triarch Repeater map	White bone tablet at the dead end, under explosive pots
Ventrium	Green statue on the right in the tunnel
Laterite	Behind a rock that drops after you approach an enemy
Gloom	In the lower stretch before the tablet

Taking the tablet starts a collapse. The far end is a dead end, so the only exit is back to the lift. Once you ride out, fallen stone seals the shaft and you cannot re-enter. One pass is all this dungeon allows.

If the map now names Crumbling Tunnel and the tablet is in your inventory, you found the right cave. The sealed lift is the final proof that the visit is finished.