Part 16 of the Mortal Shell 2 walkthrough series delves into the secret Desolate Keep dungeon, a complex and challenging area hidden within Marrow Keep. This dungeon, while not the longest, is notable for its intricate design, multiple secret passages, and a clear homage to an iconic level from a classic game. The Desolate Keep presents a significant challenge compared to other areas in Fainweald, making it a late-game objective. This guide provides a comprehensive walkthrough to achieve 100% completion, detailing every secret and enemy encounter.
Entering the Desolate Keep
The entrance to the Desolate Keep is concealed behind an illusory wall marked with a white symbol in Sester Genessa's room within Marrow Keep. After passing through the illusory wall, ensure all four chains connecting the censer to the walls have been cut. Interacting with the censer then initiates "Commune With Chaos," transporting the player into the Desolate Keep.
Clearing the Left-Hand Passage
Upon entering, players will find a rectangular pool with a Leechtongue emerging from it on the left and Brigands awaiting. An Armed Knave patrols the far side of the pool. It is advisable to first loot the 3x Weltcaps by the near pillar on the right side of the pool. Cross the pool and prioritize eliminating the Armed Knave while it is distracted by the Leechtongue and Brigands. After defeating the Knave, deal with the Brigands and the Leechtongue, utilizing nearby explosive barrels for an advantage. These Brigands are notably tougher and more resistant to staggering than previously encountered enemies. Once cleared, collect the 3x Weltcaps from the corner nearest to where the Brigands were. Proceed further down the left-hand passage to defeat two more Brigands at the base of a staircase. Ascend the stairs to confront another Armed Knave and three Brigands, including two Crossbowmen. After their defeat, players can collect 2x Burnt Effigies and 3x Common Moonshine from nearby tables, and a chest at the base of a statue contains 500x Coin. Return down the stairs and find a lever behind a pillar to the left. Pulling this lever opens a new ramp leading from the pool into a courtyard, though this path will be revisited later.
Navigating the Main Chamber
Proceed along the left side of the pool, which was the far side initially. Around a few corners, an Armed Knave guards what appears to be a dead end. Defeat the Knave, and the wall ahead will open, revealing a larger main chamber. This area is populated by a Headsman, several Brigands, and two Subjugated Sentries—enhanced versions of the Stoner enemy that attack with ballista-like projectiles. The strategy here is to lure the Headsman and Brigands away from the Sentries for easier elimination, then engage the Sentries in close combat. Following their defeat, five more Brigands will spawn; these enemies are also difficult to stagger and deal significant damage, requiring careful engagement. The chest previously guarded by the Sentries yields a Tooth Of Nochte, and 2x Common Moonshine can be found on either side of the steps. At the very back of the chamber, players can collect Martyr's Ash and find a path forward. Defeat the Subjugated Sentry blocking the way and enter the next room.
Defeating the Necrite
The subsequent room features a zigzagging wooden platform over another pool. This area is guarded by a Leechtongue on the platform, and the pool contains various Bloodcursed Skulks (a variant of Skulks that inflict Bloodcurse) and another Leechtongue. Eliminate all enemies in this room. A Brigand Stoner is positioned on an upper platform in the back-left corner, accessible only via ranged attacks. After clearing the room, collect the 11x Weltcaps within the pool. Proceed to the corridor at the far end, where a Necrite awaits. This enemy, similar to one encountered in Mushroom Village, features a sweeping first strike that requires precise timing for parrying. Defeat the Necrite.
Obtaining the Blackmarrow Key
Continue towards the far wall behind where the Necrite was. This wall will ascend, revealing a new room filled with explosive barrels, Wretches, and another Subjugated Sentry. Defeat these enemies. Grated walls on either side of this room conceal Armed Knaves, which can be accessed and defeated by heading around the far corners. Once the room is clear, approach the far wall, which will open to reveal a final chamber containing a chest. Opening this chest yields a Blackmarrow Key, similar to the one obtained after defeating The Lost Child. A teleportation orb is located behind the chest, but it should not be activated yet.
Unlocking the Passage Below the Stoner
Return to the room with the zigzag platform and the Brigand Stoner. A new pathway has opened beneath the platform in the corner where the Stoner was located. This passage became accessible after crossing an invisible threshold in the preceding room. Inside, players will find 3x Ventrium. A lever on the opposite wall initially appears inactive. This lever operates an elevator, but the elevator shaft must be revealed first. To do this, return to the zigzag platform room and proceed back towards the main chamber. Passing a specific invisible threshold will activate the elevator. Go back into the secret room off the zigzag room, where the elevator will now be present beside the lever. Ride the elevator to the top and follow the path to find a Dorsalite on a throne. This secret passage does not grant access to the Stoner's ledge. Drop off the ledge to the left to return to the zigzag room.
Defeating the Grisha in the Courtyard
There is one final area to discover: the courtyard previously glimpsed. From the zigzag room, re-enter the corridor where the Necrite was fought. Approach the righthand wall, which will open to reveal another secret passage. Descend the stairs and defeat two Foul Knights that emerge from iron maidens. Continue up the stairs around the next corner to enter the courtyard. This courtyard contains a Grisha in the center of a pool. Defeating the Grisha rewards players with a Grisha Remnant, and an item in the pool provides a Glimpse. Additional loot, consisting of 3x Martyr's Ash, can be found on the wooden execution platform in the near-left corner.
Exiting the Desolate Keep
With all objectives completed, backtrack from the courtyard to the corridor behind the zigzag room. Proceed to the end of the dungeon where the Blackmarrow Key was obtained and activate the glowing light to be transported back out of the Desolate Keep.
This concludes the walkthrough for the Desolate Keep. The next installment will guide players through the Outskirts of Mammon, a more perilous region south of Marrow Keep.