Mortal Shell 2 Crumbling Tunnel Dungeon Walkthrough

The Crumbling Tunnel is a mid-game dungeon in Mortal Shell 2 that connects the Sunken Grotto to the Ashen Plateau. This walkthrough covers the full path, every item location, the boss fight, and the optional secret area, so you can clear it without missing anything.

Background: Where the Crumbling Tunnel Fits

Mortal Shell 2 (2024) is a souls-like action RPG by Cold Symmetry. The Crumbling Tunnel is the third dungeon you’ll likely encounter after the Festering Bog and the Sunken Grotto. It’s a short, linear cave system with a few branching side paths. The dungeon is notable for its narrow ledges, falling rocks, and a mini-boss that guards the main exit. You’ll find it by heading east from the Sunken Grotto’s central bonfire, through a rock archway that leads to a steep descent.

How to Reach the Crumbling Tunnel

Before you can enter, you need the Grotto Key, which drops from the boss of the Sunken Grotto, the Mire Warden. After defeating it, return to the central bonfire and take the eastern path. You’ll see a locked gate; use the key to open it. The tunnel entrance is about 30 meters ahead, marked by two broken pillars. If you haven’t beaten the Mire Warden, you can’t access this area, so make sure you’ve cleared the previous dungeon first.

Full Walkthrough: Path and Enemies

Once inside, you’ll follow a linear path with three distinct sections. Here’s the step-by-step route:

1. Entrance Hall: After entering, you’ll see a broken bridge to your left (unusable) and a straight path ahead. Go straight, and you’ll encounter two Grotto Crawlers (small, fast enemies). Take them out with a heavy attack to stagger them.
2. First Fork: You’ll reach a split. The left path leads to a dead end with a Resin Lump (upgrade material). The right path continues the main route. Grab the resin first, then go right.
3. Collapsed Corridor: A section of ceiling has fallen, blocking a side passage. You can crawl through a gap on the right side. Inside, you’ll find a Glimmering Nectar (healing item) and a note that hints at the secret exit (see below).
4. Narrow Ledge: The path narrows to a single-width ledge over a pit. Walk slowly to avoid falling. Two Rock Throwers (ranged enemies) will lob stones from above; use a bow or throw a spear to knock them off.
5. Boss Arena: The ledge ends at a large circular chamber. This is the boss fight (detailed below).

Boss Fight: The Stone Golem

The boss is a Stone Golem, a large humanoid made of rock. It has two phases:

• Phase 1 (100%–50% HP): The golem uses slow, telegraphed swings. It also slams the ground, creating a shockwave that you need to jump over. Attack after its combos (1–2 hits max).
• Phase 2 (below 50%): The golem’s arms become covered in lava, adding fire damage to its attacks. It also gains a new move: a rolling charge across the arena. Dodge sideways to avoid it.

Recommended strategy: stay close to its back leg, attack twice, then retreat. Use a weapon with high stagger (like the Great Hammer) to break its poise and land a critical hit. When it charges, roll toward it (not away) to i-frame through. After defeating it, you’ll get the Golem’s Core, a key item needed to open the Ashen Plateau gate.

All Loot and Item Locations

There are 7 items total in the Crumbling Tunnel. Here’s where to find each:

• Resin Lump – Left fork at the first split (dead end).
• Glimmering Nectar – In the collapsed corridor, behind the crawl space.
• Ancient Scroll – On a ledge above the narrow walkway (jump from the rock pile near the second Rock Thrower).
• Tarspoon (weapon) – In a hidden alcove behind a fake wall in the boss arena (hit the wall to reveal it).
• 2x Grotto Shards – One on a corpse near the entrance, another in the collapsed corridor.
• Golem’s Core – Boss drop (mandatory).

Secret Exit and Optional Area

There is a hidden exit that leads to a small optional area with extra loot. To find it:

1. In the collapsed corridor, read the note on the corpse. It says: “The tunnel breathes where the rocks weep.”
2. After the boss, return to the collapsed corridor. Look for a wall that has water seeping through cracks (the “weeping” rocks).
3. Hit the wall with a heavy attack – it will crumble, revealing a narrow passage.
4. Follow it to a small cave with a chest containing a Unique Weapon: Stonebite (a hammer that deals extra stagger damage) and a Lifegem.

This optional area is not required for progression, but it’s worth grabbing the weapon.

Common Mistakes and Tips

• Falling off ledges: The narrow walkway is the most common death spot. Use the lock-on to keep your character facing the enemy, and don’t sprint.
• Missing the secret wall: Many players miss the fake wall because it looks identical to other rocks. Look for the water drips – they’re subtle but visible.
• Not using the Golem’s Core: After the boss, you must use the core at the gate to the Ashen Plateau. If you don’t, you’ll be stuck. The gate is directly behind the boss arena.
• Underleveled: If you’re struggling, make sure you’ve upgraded your weapon at least twice and have 5+ healing items. The golem hits hard.

Frequently Asked Questions

How long is the Crumbling Tunnel?

It’s a short dungeon – about 15-20 minutes if you rush, 30-40 minutes if you explore everything. It’s the smallest dungeon in the game.

Can I skip the boss?

No, the Stone Golem is mandatory. It drops the Golem’s Core, which you need to open the gate to the next area. You cannot proceed without it.

What level should I be for this dungeon?

Recommended level is 15-20, with at least a +2 weapon. If you’re below level 12, consider farming the Sunken Grotto for tar and upgrade materials.

Is the secret weapon worth getting?

Yes, the Stonebite hammer has high stagger damage and is useful against armored enemies. It’s one of the best early-game weapons for a strength build.

What happens after the boss?

Use the Golem’s Core on the large gate behind the arena to open the path to the Ashen Plateau. You can also fast-travel back to the hub from the bonfire that appears after the boss.

Are there any missable items?

Yes, the Ancient Scroll and the Stonebite are missable if you don’t explore. The scroll is on a ledge you can jump to, and the weapon is behind a fake wall. If you leave the dungeon without grabbing them, you can’t return until New Game+.

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