Seat of Infinity Guide – Mortal Shell

The second location you can visit in Mortal Shell is the Seat of Infinity. This location is accessed through the right side of Fallgrim via a path that leads down to a large structure. Like the other unique areas in the game there is a boss at the end of this area called Crucix, The Twiceborn. When Crucix is defeated you will gain access to the Knotted Gland item needed to advance your story progress. To make your way through this area use our Seat of Infinity guide.

Exploration: Due to the game’s gland/fog mechanic you will want to explore each location as much possible prior to fighting the area’s final boss. This mechanic causes the level to change when a gland is acquired. The Seat of Infinity changes drastically when you defeat the boss, cutting of access to much of the Dim Gate area. This area remain this way until you reset them by entering NG+.

Seat of Infinity Map and Guide

Image showing a map of the layout of the Seat of Infinity in Mortal Shell.

The Seat of Infinity is a much larger structure than the Shrine of Ash as it contains a number of areas for players to explore. These areas are split into three distinct locations:

  • Eternal Narthax.
  • Dim Gate.
  • Shifting Archives.

Both the Eternal Narthax and Dim Gate locations are confusing to traverse as they are large areas with multiple paths. The Shifting Archives is the final area with the boss.

Weapon: Hammer and Chisel

Image showing the Hammer and Chisel location in Mortal Shell.

When you enter the first room of the Seat of Infinity you will be in a large room called the Eternal Narthax. In this room along the left side you will see a workbench, Sester Ganessa, and a weapon statue. The weapon statue here is for the Hammer and Chisel. If you want to get this weapon interact with the book and fight the Hadern wielding the Hammer and Chisel. Defeat this boss to unlock this weapon for your own use.

How to Get through the Eternal Narthax

Image showing How to Get through the Eternal Narthax in Mortal Shell.

Make your way to the far side of the room and head through the double-doors there. In this large open area you will need to use the golden teleporters marked with numbers on the map above. These teleporters will take you from one part of the area to the other. To advance deeper into the area use either teleporter 1 or 2 to end up in the upper left corner on a walkway. Head to the right (when facing the building) on this walkway until you reach a large ramp going down. Go down the ramp to reach the golden switch pictured above. Activate this switch.

To advance further in this room you need to activate two more switches to allow for a pressure plate to be pressed on the ramp leading into the large building. These switches are located on both the left and right sides of this large room (shown on map with yellow dots). Head to these switches and activate them now. Both can be reached by heading in the respective directions from the middle switch we activated. Keep in mind this area is crawling with enemies so be prepared to fight or run.

Image showing the pressure plate to stand on in the

Once you’ve activated all of the switches head back to the large ramp and go up it so you reach the pressure switch shown on the map by the yellow square. This pressure switch can now be activated to open the large gate heading into the building. Go up through this gate to reach the Dim Gate section of this area.

How to Get through the Dim Gate

Image showing how to get through Dim Gate in Mortal Shell.

Head forward through the first section of the Dim Gate until you reach the long room with the statue where you can go straight, right, or left. Go right here to reach a Sester Ganessa. After you’ve triggered this checkpoint head back to the statue and head up behind to it to find a staircase going up. Follow this staircase up to reach the second floor.

The second floor is a huge room you can feel free to explore. In this room you can interact with the gold switch to get a number of items of loot. Once you’ve explored you will want to make your way through the left corner exit to reach another stair area that leads up to the even more massive floor three.

Reaching the Shifting Archives

Image showing how to reach the Shifting Archives in the Seat of Infinity area.

The third and final floor is a super long sequence that requires traversing a path floating in the sky. This path leads to the boss room which is the Shifting Archives. Before doing anything I recommend unlocking the elevator shortcut back down to floor one. This makes the run back from Sester Ganessa more bearable. The elevator can be found on the far right side of this floor when facing the floating path. The easiest method of getting to this location is to use the teleporter marked with 5 as it takes you right there. Stand on the pressure plate to send it down below.

Side’ Quest: In this location you will find a man named Brether Corvid who is tied up at the edge of a ledge to the left of the floating path entrance. Knock him off the ledge to get the Glimpse of Cowardice item from him or complete his other quest-line.

Once you have the elevator unlocked the goal is to make it to the Shifting Archives. Make the long trek past the various enemies on the floating path until you reach the boss location. As you approach you may notice a giant Sester Ganessa on the left side of the Shifting Archives room. Interact with her to get a checkpoint then head over to the goblet and take a sip to cause the floor to cave-in.

Boss: Crucix, The Twiceborn

Image showing the Crucix boss from Mortal Shell.

Important: End of area bosses always have two health bars. Don’t celebrate when you drain the first health bar. Be ready for the second phase. Also important you will take fall damage before the start of the fight as the floor with the goblet will cave in. The only way around this is to have ground pound ability unlocked which you can use to negate the fall damage by activating it before you hit the ground.

As the name of this boss implies, there are two bosses for players to (sort) of fight. There is one body but two bosses in one. The main body boss is melee-centric. This boss wields a hammer and spear. In the boss’ chest there is a small twin that has a crossbow. What this means is you have to deal with both melee and ranged attacks during this fight. Thankfully for us the melee/range combination only lasts for the first phase.

During the first phase you will need to watch out for a number of attacks from Crucix. These attacks are predominantly melee but he will take a knee occasionally to let the ranged part of his body shoot at you. Besides this ranged attack Crucix only has one other where he jumps into the air and peppers you with arrows before crashing down on top of you with his spear. Once you deplete Crucix first health bar you will trigger a cutscene where his chest twin dies. This means no more ranged attacks which is good for us.

In the second phase Crucix becomes tankier and has longer melee combos he uses. Keep your distance and pick you spots for a quick hit and run. Eventually Crucix will fall and you will be the victor. Like the last boss fight you can loot his body for a Glimpse of Oblivion before you are teleported back to the Shifting Archives where you can grab the Knotted Gland out of the skull’s fleshy meat sack tongue.

Back to Fallgrim Tower in the Fog

When you pull the Knotted Gland you will plunge the level into fog. This alters the level closing off a number of paths that were previously open. To head back to Fallgrim Tower you need to make your back through the level to the elevator shortcut. You then need to take the shortcut down and head back through the level using teleporter 1 to return to the beginning of the Eternal Narthax area. Leave the area and head out into the Fallgrim Outskirts. Retrace your steps along the cliff path to head back to the Old Prisoner in the tower. Give him the Knotted Gland to remove the Fog.

Once you’ve delivered the Knotted Gland you will only need one more gland to complete the game. This final gland can be located in the Crypt of Martyrs which is accessed in the Fallgrim Outskirts. Along the way we will grab the fourth and final shell, Tiel.

Fallgrim >

Thoughts on our Seat of Infinity guide for Mortal Shell? Drop them in The Pit below.


Enricofairme is the founder and lead writer on He has been creating content about video games for the past 6 years. You can follow Eli on Twitter @enricofairme.

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