The Sanguine Caverns, located at the northernmost point of Mortal Shell 2's map, serve as the final challenge in the Fainweald region and house the game's third major boss, the Lost Child. This guide details a step-by-step walkthrough of the entire area, ensuring players can find every item and overcome every obstacle.
Navigating the Caverns
Begin by crossing the north bridge from the Cavern Entrance Beacon. As you enter the white expanse of the Sanguine Caverns, be prepared for an immediate assault from Children Of Gloom. After dispatching them, proceed into the blood-red area ahead and defeat the Infested Stalker. Ignore the downward slope to your left for now, and continue forward to find a Gloom Tentacle guarded by another Child Of Gloom. After harvesting the tentacle, destroy the suspicious stalagmites to reveal a lootable corpse containing a Glimpse.
Turn back and take the slope downwards. Eliminate the Netopyrs in the tree and the Lithopods on the cliff edge, then loot the tree for a Ventrium. Continue along the main path, dealing with more Children Of Gloom, and drop into the air current to reach the Abandoned Camp. Here, loot the stone slab for Gloom and an Egon's Stone, a tent for Common Moonshine, and a Synaptic Vessel near some boxes.
Clearing the West Side and the Hidden Keep
From the Abandoned Camp, take the left-hand path to clear the west side. After finding a sitting spot and some Common Moonshine near a tree, proceed along the main path, defeating the Children Of Gloom and Stalker. Loot the two Laterite deposits and head down the adjoining slope. Collect the Tooth Of Nochte to your right, then turn to face and defeat the Headsman and three Brigands. Drop to the lower platform, clear out the spawning Children Of Gloom, and loot a pouch of 350x Coin and two Common Moonshine from an abandoned camp on the left. A Ventrium can be found in an alcove further ahead. A stone bridge guarded by a Brigand Stoner lies at the far end, but it leads back towards Gloomshade Grove and is not a necessary path forward.
Return to the Abandoned Camp and take the central, blood-red path north. This leads to the Stonebled Gate Beacon and the entrance to the region's legacy dungeon. Activate the Beacon and enter the Hidden Keep. In the first room after the elevator, take the first left, squeeze through a gap behind crates, and defeat the Nocteserper to loot a Bone Statue for a Laterite. Retrace your steps, head to the end of the path, turn right, and destroy crates to find another Nocteserper. Press the stone button on the wall to reveal a path forward.
On the bridge ahead, defeat the Brigands and Nocteserpers. On the circular platform, you will be ambushed by Lucian, the Thirsting Knight. After Lucian retreats at half health, teleport up to the Bone Gate and follow the path to a gap. Squeeze through to find Lucian again in the final room of the Hidden Keep. He will reappear, now largely invisible and using claws. Defeat him to acquire a Glimpse and the Serpent Stone, which infuses weapons with Poison. Cleanse the corruption to receive 3x Ova and an additional Glimpse.
Into the Legacy Dungeon
Cleansing the Hidden Keep opens the gateway beyond. Head through the gateway and down the steps into the Sanguine Caverns legacy dungeon. Collect the Ventrium from a statue and defeat the Lithopods. Around the corner, dispatch the two Infested Stalkers. Head down the slope, dodge the exploding bloated corpse, and destroy the Bone Statue for a Laterite. Backtrack to the side passage where the last Stalker emerged, defeat the Brigands and the Brigand Stoner, and open the chest to acquire the Deadeye Stone, a Tarstone that enhances ranged critical damage.
Drop down the hole near the wooden platform and defeat the group of Brigands. Loot a Laterite from the corner behind destroyed crates. Head up the slope, eliminating Infested Stalkers and Netopyrs. Deal with more Children Of Gloom, then strike the wall of stalagmites to the left of the main path to find a Synaptic Vessel.
Continue along the main path. As you cross the bridge to reach the Pulsing Caves Beacon, it will fall, sending you down. Dodge the exploding bloated corpses, kill the Child Of Gloom, and clear the remaining corpses. Loot a Ventrium from a statue by the wall. Proceed across a series of bridges, carefully dealing with exploding Netopyrs from a distance using your Crossbow. Use the Bone Gate to cross a gap, loot a Ventrium from a patch of bloody ground, and defeat the Children Of Gloom that appear. You can choose to fight the large group of Lithopods around a red hole or bypass them to activate the Pulsing Caves Beacon.
Mawbreak Cavern, Hermit's Pass, and Boss Encounters
Rest at the Pulsing Caves Beacon and Cleanse it to enter Mawbreak Cavern. Navigate past bloated corpses, defeat Netopyrs and Children Of Gloom, and cross two bridges. Loot a Bone Statue for a Laterite. Follow the path to a chest guarded by Lithopods; defeat them and open the chest for the Blackblood Stone, a Tarstone for the Naylshotte. Detonate the bloated corpses surrounding the corruption and loot the Ovum within to return to the Beacon, earning a Glimpse.
Use the Beacon to access Hermit's Pass. Cross the bridge, defeat three Infested Stalkers and three Netopyrs. Squeeze through a gap, break stalagmites to find a Dorsalite, and loot a Revered Gland from the cave ahead. Cleanse the corruption to receive an Ovum and a Glimpse.
Return to the air current and use it to go back to the Sanguine Shoreline Beacon. Traverse the gap using the Bone Gate. You will encounter the Tarblighted Stoner, a miniboss that attacks with multiple boulders and summons Tarred Corpses. Evade the minions while focusing on the Stoner. Defeating it yields the Tarred Fragment, an Ability Tarstone for the Salvaged Trebuchaxe.
After defeating the Tarblighted Stoner, use the air current to reach an upper ledge. Follow the path and squeeze through a gap behind Ruk to trigger a cutscene introducing the Lost Child, Mortal Shell 2's third major boss. The Lost Child's attacks include leaps, lunges, claw strikes, a projectile stream from its rear, and an area-of-effect breath attack. Dodge its leaps and lunges, parry its claw strikes. For the projectile stream, spam dodge to the side. For the breath attack, move close to the boss while it's inhaling and then run around it. Upon defeat, you will receive the Lost Clotstone and 11000x Gloom.
Final Steps in Fainweald
Activate the Child's Feeding Grounds Beacon that appears after the boss fight and enter it. Cleanse the corruption to collect Ova, then head through the doorway to find a chest containing a Blackmarrow Key. These keys can be used in Marrow Keep to unlock cosmetic skins for your Shells. Collect the 26x Ova to be transported back to Marrow Keep. You will have a communion with the UnderMether, who speaks of the Foul Passenger.
Back at Marrow Keep, use the Gloom Siphon to collect your rewards, including 3x Glimpse and 12x Dorsalite. To complete the Fainweald cleanup, use Mether's Breath to fast travel to the Outskirts Of Nochte Beacon. Head south through archways and enter the cave of the Nightfish. Interact with the Nightfish to hand over Mether's Flesh. This will transport you to the Mango Sanctuary, where you can interact with a gigantic mango at the base of a tree to receive a Mango item, which restores 50% health or enables a cosmetic Mango Mask. Interact with the glowing orb behind the tree to return to the Nightfish's cave, then travel back to Marrow Keep. Fainweald is now fully conquered, with the next stage of your journey awaiting.