Mortal Shell 2: Chamber of Becoming Location and Full Walkthrough

The Chamber of Becoming is the dungeon in the Ruins of Mammon that hands over Sariel — the last of Mortal Shell 2’s eight Shells — along with a new primary weapon and a sidearm. It is not marked on your map until you provoke the fight that opens it, and the boss inside genuinely cannot be killed until you deal with the arena first.

Quick answer: Fast travel to The Silent Steps Beacon, head southeast onto the large stone platform and fight Sariel until he flees, follow the path he tears open into the Chamber of Becoming, then smash all four glowing tombstones in the final arena before landing the killing blow.

Chamber of Becoming rewards

Three items are locked behind this dungeon. Clearing it once gets you all of them, and none of it can be picked up early or bought elsewhere.

Reward	Type	How it drops
Clockwork Scythe	Weapon	Awarded the moment Sariel, the Endless stays dead
Sariel	Shell	Interact with the Unknown Shell on the floor, then finish the memory
Caged Hystrix	Sidearm	Found in the final chamber after speaking to the giant crow, Rok

Chamber of Becoming location and how to reach The Silent Steps

The dungeon sits in the Silent Steps sub-location in the far south of the Ruins of Mammon. If you already have The Silent Steps Beacon, skip ahead — everything below is just the first trip out there.

Start at the Outskirts of Mammon and take the Road to Absolution. At the end of the road, drop off the cliff edge to transition into the next area rather than looking for a path around.

Push through Castigator’s Keep and activate the beacon there. The enemies patrolling the keep can be outrun if you are underlevelled, so there is no need to clear the whole area on the way in.

Player sprinting toward the stone staircase running alongside the keep wall on the route south — The stone stairs beside the keep wall on the way through to Barren Crest. Image: Cold Symmetry

Cross the wooden bridge past the keep. Spider-like enemies guard the far side, and the Barren Crest beacon is just beyond them. Cleanse it before moving on.

Climb the stone stairs, cross the next bridge, and you arrive at The Silent Steps Beacon. That is your anchor point for everything that follows.

Alternate route from the Vestige of Infinity

If you are coming from the Gate of Infinity Beacon instead, leave the gate area and go down the first flight of stairs. Turn east and exit the Vestige through that opening, cross the narrow rocky bridge, then drop to the ground below it. The cave there has only one path, and it ends at The Silent Steps Beacon.

How to unlock the dungeon: beat Sariel on the snowy platform

The entrance is sealed until Sariel opens it himself. From the beacon, use the Bone Gate to reach the tall brutalist structure southeast of you and walk out to its central extension. He appears and attacks on sight, labelled here as Sariel, the Godless.

Armored character running up the snow-covered fortress platform where Sariel ambushes you — The snowy platform southeast of The Silent Steps Beacon, where the first Sariel fight starts. Image: Cold Symmetry

You do not need to grind this one out. Once he takes enough damage he retreats south through the walls, and that collapse is what opens the route to the dungeon. Mind the ledges — the arena has open edges on several sides, and knocking him off works just as well as wearing him down.

Follow his shadow. The path runs behind the large statue and down a set of stairs toward a pool, where a heavily armored Knight of Mammon stands guard over the entrance. Kill it rather than trying to slip past, because it will follow you into the drop. Grab the loot scattered along the way, then drop into the Chamber of Becoming.

Crossing a snowy rooftop on the way down to the dungeon entrance with Gloom and Glimpse pickups on the HUD — Gloom and Glimpse pickups line the snowy approach down to the dungeon entrance. Image: Cold Symmetry

Break the four tombstones before killing Sariel, the Endless

Inside, Sariel — now titled the Endless — blocks your way again. This is a short encounter. Take him down to roughly ten percent health and he pulls back once more, a wall slides open, and the deeper section of the dungeon becomes accessible. Drop into his main arena to finish it.

The final room has a sigil on the floor and four glowing tombstones ringing the space. Those stones are the reason his health bar means nothing. Kill him without touching them and he simply gets back up, indefinitely.

Attack each of the four stones until it shatters. With all four gone he stops resurrecting, and the next time you drop him he stays down. The Clockwork Scythe is awarded immediately afterward, and the game prompts you to interact with him.

Clockwork Scythe pickup and the Unknown Shell lying on the arena floor after the fight — The Clockwork Scythe drops first, with the Unknown Shell waiting on the arena floor. Image: Cold Symmetry

Unlock the Sariel shell through “The Search” memory

Sariel’s body is left on the arena floor as an Unknown Shell. Interacting with it gives you the Inhabit Unknown Shell prompt, and accepting drops you straight into a Shell Memory titled “The Search.”

The memory plays out in a frozen library. Work through it to the pillar at the end and extract the gland from it. That single action closes the memory and permanently unlocks Sariel as a usable Shell — you will be back in the dungeon with him listed alongside your other Shells.

The Search shell memory objective on screen as the character inspects the icy wall in the frozen library — “The Search” shell memory, where extracting the gland finalizes the Sariel unlock. Image: Cold Symmetry

Note: the Shell only counts as unlocked once the memory is finished. Interacting with the body and backing out before the gland is taken leaves it incomplete.

Caged Hystrix sidearm location

Do not leave straight after the memory. The giant crow NPC, Rok, is waiting in the last chamber. Speak to him, then pick up the Caged Hystrix sidearm sitting nearby. It is easy to miss entirely if you exit through the dungeon door on autopilot once the boss is dealt with.

Common reasons the Chamber of Becoming will not open or finish

The entrance is still walled off. The route south only opens after the first Sariel fight on the platform. Wandering the Silent Steps looking for a door will not find one.
Sariel keeps getting back up. One or more of the four tombstones is still intact. Break every one, then attack him.
No Shell appeared. The Unknown Shell only spawns after the final kill sticks, not after the earlier retreats.
The sidearm is missing. The Caged Hystrix is in the last chamber with Rok, not in the boss arena itself.

None of this is missable. Sariel is typically the last Shell most players collect, and the dungeon stays open in free roam after the final boss, so a late clean-up run before New Game+ works just as well as tackling it on schedule.