Weapons in Mortal Shell are upgraded using items found in the game world. Each has two unique items used to unlock weapon abilities, then they can have their damage upgraded a total of 5 times using an item called Quenching Acid. There are a total of 10 Quenching Acid that can be found during a playthrough (2 in each area + 2 purchased), which means if you want to spend them all on the same weapons in your first playthrough you could acquire 2 x +5 weapons.
In NG+ you can upgrade weapons to +10, as well as rebuy the 2 Acid from Vlas, as well as purchase 8 Acid from Sester Genessa for 10 glimpses each.
Each of the two weapon upgrades that provide unique weapon abilities are found in the weapon’s respective “area”. Hollow Sword upgrades are found in Fallgrim, then the other weapons upgrades are each found in the region the weapon is obtained in. In NG+ any of the upgrades you picked up prior are replaced with a Quenching Acid.
Redoing the weapon unlock fights in NG+ after unlocking the weapons in a prior playthrough also gives another Quenching Acid, so in NG+ in total you can obtain 31 total Quenching Acid if you got everything first playthrough.
The Tarnished Seal is upgraded using two types of items. One of them is the Solemn Offering, which allows you to heal more using the Empowered Riposte after a successful parry. There are three Solemn Offerings in the game, one in each of the 3 areas leading to the story bosses. The other item is the Forbidden Offering, which boosts overall resolve gain.
These are not directly tied to any trophy / achievement but it’s helpful to know where all the upgrade materials are. After beating the game you can choose to stay in your current playthrough to keep exploring and pick up your missing items and collectibles.
Quenching Acid
“A rare acid used to enhance weapons.”
1 & 2. In Fallgrim Tower, two Quenching Acid can be purchased from Vlas for 2500 tar each.
3. In the Fallgrim area, follow the path to where you fight Grisha for the first time, then through the hole on the left towards the entrance to the Shrine of Ash area. Continue forward and instead of going up the stairs, follow the lower path past the burning corpse towards the brigand camp up the hill at the end. Here is a chest where you can find a Quenching Acid.
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4. In the Fallgrim area, after you have defeated a boss and have returned a gland, you can now open the previous locked strange chests when the fog is active in Fallgrim. In front of Fallgrim Tower, near the fallen log over the path leading to the first Grisha cave, there is a chest to the left of the path that will now be lit up that you can open to obtain one acid.
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5. In Shrine of Ash, in the Monument of Ash area, follow the path to the point where there is a split, with a locked door on the right, and the path continues on the left. On the left path in the next room, there are iron maidens on the right side. Interact with the one in the middle to receive this item.
6. In Shrine of Ash, still in the Monument of Ash area, continue along the path from the above Acid. You’ll reach a large room with an enemy inside a cauldron in the middle. Go through the door to the right, then take the left into the long hallway with the two shield knights in it and a locked door at the end (if you’ve not opened it.) In the room with the knights, you can open another iron maiden on the left of the room to find this acid.
7. In Crypt of Martyrs, in the Abandonded Chamber area, follow the path from the entrance until you reach the room with the three exits, then go down the hallway to the left. Keep following the left wall and you will reach an area with an enemy with large arm blades knelt on the ground by a chest. In this chest, you can find an acid.
8. In Crypt of Martyrs, in the Enshrined Sanctum area, in the second section after defeating Enslaved Grisha, follow the path down until you reach the room with the crawl hole on the left side. Go through, then at the end of this area with a couple of ghost enemies is a chest containing this acid and another item.
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9. In Seat of Infinity, in the Eternal Narthyx area, in the first section go to where you find the right side switch for the door (right from starting area). Facing away from it on its platform, you can walk through a small area of rocks where there will be one crossbow enemy and two of the red sword enemies. Behind where the crossbow enemy stands you can find a chest containing an acid.
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10. In Seat of Infinity, in the Dim Gate area, follow along the path until you reach the platform at the top where you can continue forward, or go through the two teleporters behind. Facing the teleporters, the left one goes to the shortcut elevator to get back to the start of this area, but the other leads to a platform with a large hole down the middle and a number of platforms leading down. To reach this acid you need to drop down all these platforms to the bottom, where you can then find another teleporter. This teleporter takes you to a platform, where at the end you can find this acid. You will want the “Recollection of Knowledge” ability unlocked on whichever shell you are playing as while you grab this (or playing in obsidian dark form) so that you can use the harden drop attack to stop from taking damage while going between platforms, as the distance between most of them once you start dropping down will damage you.
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Weapon Ability Upgrade Items
1. Mechanical Spike
“A Spike that can be embedded within the Hallowed Sword.”
Acquired from the chest located in the room with the first Grisha boss fight in the forest.
2. Molten Spike
“This molten spike fits perfectly inside the Hallowed Sword.”
Once you have obtained one Gland and can enable the fog in Fallgrim, return to the brigand camp area where you could obtain the Impervious Lute, and you can find this weapon upgrade inside a locked chest.
3. Foundry Stone
“This Foundry Stone was once meant to alight a Smoldering Mace.”
In Shrine of Ash, in the Temple Grounds area, follow the path forward to where it splits, then go down to the right to a room where you can interact with stone. After you do it will give you this item, then spawn two ghost enemies. This is used to upgrade the Smoldering Mace.
4. Awakened Stone
“Given the linework, this stone would surely fit the Smoldering Mace.”
In Shrine of Ash, in the Monument of Ash area, continue along the path until you reach the large wooden bridge leading to a crypt. Interact with this crypt to obtain this item, along with spawning two of the tall sword enemies.
5. Petrified Winterglass
“This shard of winterglass fits inside of the Martyr’s Blade.”
In Crypt of Martyrs, in the Abandoned Chamber area, follow the path forward to the room with the three exists, then crawl through the path on the right. In front of the large coffin in the center of the room you can find this item.
6. Radiant Winterglass
“This winterglass gem could be nestled inside the Martyr’s Blade.”
In Crypt of the Martyrs, in the Enshrined Sanctum area, follow the main path down to the right and across the bridge. Go down the stairs in the circular room, then through the door with the metal grating on either side. In the next room there will be two of the sword enemies, along with a shield one at the back behind a chest. In the chest you can find this item.
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7. Perfumed Censer
“An incense holder that connects the Hammer and Chisel.”
In Seat of Infinity, in the Eternal Narthyx area, you can find this on the ground directly behind the switch on the right side of the area (starting from the entrance facing towards the far end).
8. Foul Censer
“This foul censer may be hung from the Hammer and Chisel”
In Seat of Infinity, in the Shifting Archives area, at the start of the large stone structure with the stacks of slabs in it, go into the front left (where you Inscription 11) to also find a teleporter. This teleporter takes you to a platform where you can find this item.
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Solemn Offering
“An offering used to unlock the mysteries of the Tarnish Seal.”
1. In Shrine of Ash, in the Monument of Ash area, follow the path all the way until you reach the large circular room with the enemy in the cauldron in the middle. Go to the right side from here into another room with another cauldron enemy, then to it’s right you can find a chest which will contain one of these. This is the same room with the shortcut door you can open from this side.
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2. In Crypt of Martyrs, in the Enshrined Sanctum area, you can find one of these in a chest directly beside the Sester Genessa location, right after the room where you fight Enslaved Grisha.
3. In Seat of Infinity, in the Eternal Narthyx area, take the teleporters through until you find the left door switch (left side of the area from where you start) that is near the group of weak human enemies. Just below it (you need to drop down from where the switch is) there is a duel-sword enemy and a tall hammer enemy. Facing where the hammer enemy stands, looking left there is a gap in the rocks you can go through. At the end, there is a teleporter, which takes you up to an area where you can find a chest containing the final Solemn Offering.
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Forbidden Offering
“A perverse offering for the Tarnished Seal.”
This can be purchased from the Corrupted Sester for 3,000 tar. She is located underneath the entrance to the Seat of Infinity region. To get to her location, go to the start of the area of stone slabs, then go around the left side to the back. Here there is a doorway in the wall, leading to a small area where this Sester is located.
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More Mortal Shell Guides:
- Mortal Shell – All Shell Locations
- Mortal Shell – All Item Locations
- Mortal Shell – All Secret Lore Locations
- Mortal Shell – Boss Guide (All Bosses, No Shell/No Damage)
- Mortal Shell – Trophy Guide & Roadmap
There’s an acid in the end of Dim gate: here