Mortal Shell 2 Blackmarrow Keys: Locations, Shade Chests & How to Use Them

The current launch-window working model is eight Blackmarrow Keys and eight matching Shade chests around the Marrow Keep elevator room. One key opens one Shade chest and is consumed. This guide gives direct instructions for five key locations. A separate report names an additional Conquered Temple/Ova location, but it conflicts with the Child’s Feeding Grounds route and remains unverified.

An earlier launch-build comparison recorded an eight-versus-nine key-count conflict. Until a key-specific launch checklist resolves it, treat the eight-key figure as the working model rather than a verified complete location database.

Blackmarrow Keys open Shade chests around the elevator room in Marrow Keep.

The local Shell roster supports eight permanent Shells, so the eight-chest model is plausible. The exact chest-to-Shell order is not established here; do not assume that the visible chest order is a key order.

Opening a chest:

• consumes one Blackmarrow Key
• unlocks a cosmetic Shade for that Shell

The reward is cosmetic rather than a stat or ability upgrade.

A Shade chest cannot be opened until you have unlocked its matching Shell. Once the Shade is unlocked, use Change Shades at a Beacon to select it.

The current source-reported chest matches are listed below. Use the confirmation prompt to verify the Shell before spending a key; do not infer a physical left-to-right chest order.

These names come from the AllThingsHow Shade guide, not an in-game capture in this checkout. Devout/Obsidian and beta-related Shades are separate rewards. For Shell unlock routes, use the Shells guide.

The current local working model is eight Blackmarrow Keys in a playthrough. Earlier launch coverage reported nine, so this count remains version- and evidence-qualified.

Because each key is consumed by one Shade chest, you need all eight keys to open all eight chests.

Blackmarrow Keys are a separate system from other named keys such as the Chapel Key, Crypt Key, Damp Key, Light Keys, and dungeon-specific keys.

Enable Night Mode, then use Abandoned Outpost Beacon as the route anchor.

The Collector appears in a small clearing south of the Beacon and sells a Blackmarrow Key for 1,500 Gold. The current sources do not establish that the purchase restocks.

This guide does not assume that the key restocks.

Use the Gloombound Flame and Night Mode guide if you still need to activate Night Mode.

The Shrine of Sorrows is a Night Mode-only dungeon southwest of Mushroom Village Beacon. The source-backed progression is: enter the cocoon-like route, collect the Moonlight, Sunlight, and Starlight Sonatas, complete the mounted-head/frozen-world transition, brew the Alluring Mushrooms, take the Basement Key, and clear the basement ritual.

Complete that three-Sonata, frozen-world, mushroom, and basement progression to receive a Blackmarrow Key and Tooth of Nochte.

Use the Shrine of Sorrows guide for the full puzzle route.

A Blackmarrow Key is tied to the secret Desolate Keep route under / at Marrow Keep. For the detailed route, go to Genessa’s training area, find the arrow-marked wall near the coffins, strike it, break the four chains around the chalice, and use Commune With Chaos. The key is in a hidden end-room chest inside the dungeon.

The supported access condition for this route is having the Slayer Seal in your inventory.

You do not need to equip the Slayer Seal merely to satisfy that inventory condition.

That distinction matters because switching to the Slayer Seal has a separate achievement consequence. See the Slayer Seal and difficulty guide before equipping it.

Another Blackmarrow Key is in a chest in the Abbey Entrance area. From Abbey Entrance Beacon, take the southeast stairs into the castle, descend through Sester’s Refuge, clear the three Sester enemies by the bridge, and cross to the tower. Use Map of Mammon 1 at the statue as a landmark, then step onto the wooden scaffolding around the tower, drop to the lower path, and follow it around to the chest.

Search beneath / around the tower scaffolding for the chest.

This route is supported by a detailed launch guide but not a second independent route source in this checkout. The page keeps it at named-landmark level rather than inventing coordinates or a map marker.

This key is tied to The Lost Child and the Child’s Feeding Grounds progression. External guides also use the singular “Child’s Feeding Ground”; the plural is the local Beacon label.

After completing The Lost Child route, enter the Child’s Feeding Grounds Beacon dungeon and cleanse its corruption. The detailed source reports 26 Ova and an automatic return to Marrow Keep; the number is not needed to solve the route.

Then fast travel back to the Child’s Feeding Grounds Beacon, choose Enter Dungeon, and head to the innermost chamber / former Ova location. The key becomes available in the newly accessible secret area behind that point.

Use the Lost Child boss guide for the boss route.

GamesRadar+ lists a Blackmarrow Key “behind the Ova in the Conquered Temple Beacon.” No second source in this pass confirms that pickup. The detailed five-route sources instead place the former-Ova key in Child’s Feeding Grounds, so this may be a distinct route or a Beacon-name mix-up.

Treat this as an unresolved lead, not as a sixth confirmed location. Do not merge it into the Child’s Feeding Grounds return route, and do not use it to claim that the remaining key count is settled.

Return to Marrow Keep and go to the elevator-room area.

Choose a Shade chest for a Shell you have already unlocked.

Use one Blackmarrow Key to open it. The key is consumed and the corresponding cosmetic Shade is unlocked.

Afterward, use Change Shades at a Beacon to select the cosmetic.

This site currently routes five of the eight Blackmarrow Keys with enough confidence to give direct instructions.

The other exact locations are intentionally left unconfirmed for now. Under the eight-key model, the disputed Conquered Temple/Ova report could represent another slot, but that is not proven.

That does not change the current working model: eight keys and eight Shade chests. It only means this guide will not fill the remaining rows with speculative routes or pretend that the eight-versus-nine conflict or the Conquered Temple naming conflict is resolved.

If you are tracking completion, record:

• which of the five actionable keys you collected
• how many Blackmarrow Keys you have spent
• which Shade chests in Marrow Keep are already open
• whether you have checked the disputed Conquered Temple/Ova report

That makes it easier to identify what is still missing without mixing Blackmarrow Keys with the game’s other key systems.

The current local working model is eight, but earlier launch coverage conflicted between eight and nine. This page does not claim that the count is independently settled.

Eight, around the Marrow Keep elevator room.

No. One Blackmarrow Key opens one Shade chest and is consumed.

Its matching Shell must be unlocked before that Shade chest can be opened.

Among the five routes documented here, the Abandoned Outpost / The Collector key and Shrine of Sorrows key require Night Mode.

No. The supported route condition is having the Slayer Seal in your inventory, not equipping it.

After the Child’s Feeding Ground Beacon / Ova progression, return to the dungeon’s innermost chamber and the area behind the former Ova location.

No. Five are routed directly here; the remaining locations are not settled, and one additional Conquered Temple/Ova report conflicts with the Child’s Feeding Grounds naming.

The route details and Shade matching used in this expansion are cross-checked against AllThingsHow’s five-location guide, AllThingsHow’s Shade interaction guide, and its Desolate Keep route. GamesRadar+’s Shade guide independently supports eight chests and the Shell-matching rule, but reports a conflicting Conquered Temple/Ova location. That conflict is why this page remains needs-verification.