Fulminated Mercury Sekiro Guide


Sekiro: Shadows Die Twice puts you in the shoes of a dedicated and weary shinobi named Wolf. Wolf goes on an epic journey through FromSoftwares interpretation of Sengoku era Japan and takes you everywhere from castles to cursed forests. In your quest to serve the divine heir of Ashina your arm gets severed early in the adventure, but luckily for you, a prosthetic arm is soon given to you to help remedy that situation.

Sekiro is a challenging game. However, it’s not an impossible game, and players possess various prosthetic tools to help shape battles in their favor. Your prosthetic arm is akin to a “Wolf with different fangs,” and you will have multiple “fangs” to sink into your enemies. Everything from firecrackers to a poison-coated blade to a vent that shoots flame will be at your disposal.

However, in true FromSoft fashion, you’ll find that the base versions of these tools don’t quite cut the mustard. As you progress through the game and best bigger and more challenging foes, you’ll quickly realize that you have to maximize your resources to come out on top. The upgrade system for your prosthetics is much like the combat itself: Easy to enter, challenging to maximize.

With specific tools working better for certain situations, I quickly realized during my first playthrough that if I wanted to win, I’d have to pull out all the stops and upgrade my prosthetics. One of the more challenging items you’ll need to obtain to upgrade your prosthetics successfully is the elusive resource Fulminated Mercury. Fear not, fellow shinobis, cause we’ll tell you what it is and where to get it.

Tools Fit For A Shinobi

Throughout your adventure in Sekiro: Shadows Die Twice, you’ll have the opportunity to obtain ten different prosthetic attachments, many of which are elusive to find. Like any FromSoft game, you receive little guidance and are encouraged to explore the environment and leave no stone untouched. My favorite part of Sekiro was how complementary it is to other games FromSoft has released.

While it is a more narrative-driven and brisk experience, the battles are not superlinear, and much like Elden Ring and Dark Souls, you’re encouraged to find your own groove. Obtaining every upgrade is not necessary to beat the game, but it will make your journey less complicated and fully empower you to develop your style. Therefore, to make the challenge more reasonable, you’ll want to get as much Fulminated Mercury as possible. You won’t need (or even be able) to upgrade each prosthetic fully in your first playthrough, but you will be able to get them to their second to best form with a handy supply of this precious resource.

What Exactly Is Fulminated Mercury?

Fulminated Mercury
Image from Wiki Fandom

FromSoft is no stranger to fantasy and fantastical elements but befitting Sekiro’s more realistic approach; they based this component on reality. Fulminated Mercury, or Mercury (II) culminate, as it’s called in our world, is an augmentation of the chemical Mercury that makes things go boom. You’ll fight everything from riflemen to headless spirits of heroes past in this game, and if you want to turn your enemies into dust, you’ll need this elusive compound. While you can obtain a decent amount of it through normal gameplay, specific locales make excellent farming grounds for this material, and you best believe I’ll be sharing them with you to help you on your journey.

How To Upgrade Your Prosthetics

Wolf and the Sculptor
Image from FromSoftware.

Players must visit one of the many Sculptor’s Idols (Sekiro’s equivalent to Bonfires or Sites of Grace) to upgrade a prosthetic and travel back to the Diliapted Temple Idol. Upon transporting back, simply turn around and head straight to the Sculptor himself. Upon speaking to him, you’ll open a menu that gives you the options to add new prosthetics you may have found and upgrade the ones currently at your disposal. Each upgrade requires varying quantities of various materials. Still, other than the final Lazulite form for certain prosthetic upgrades, you can upgrade all prosthetics to their max or second to max level in a single playthrough which is what I did during my first lap in Shadows Die Twice.

Which Upgrades Need Fulminated Mercury?

Prosthetic Upgrade Tree
Image from Imgur.

Here are the upgrades and the quantity you’ll need of Fulminated Mercury for upgrading specific prosthetics. Each Prosthetic has various levels, some maxing out at level six. It is highly recommended you do so to unlock greater flexibility and help transform the high difficulty into a healthy challenge.

  • One Fulminated Mercury for level 5 Spear (Leaping Flame Upgrade)
  • Two Fulminated Mercury for Level 5 Loaded Umbrella (Suzaku’s Lotus Umbrella)
  • Two Fulminated Mercury for Level 5 Shinobi Firecrackers (Purple Flume Spark)
  • Three Fulminated Mercury for Level 5 Mist Raven (Great Feather Mist Raven)
  • Three Fulminated Mercury for Level 6 Loaded Axe (Lazulite Axe)
  • Four Fulminated Mercury for Level 6 Sabimaru (Lazulite Sabimaru)
  • Four Fulminated Mercury for Level 6 Flame Barrel (Lazulite Sacred Flame)

As you can see, Fulminated Mercury is essential for maximizing your prosthetics. Luckily you only need a total of 19 to do so, and we’ll show you where to obtain and farm for it easily.

Which Enemies Carry Fulminated Mercury?

Snake Eyes Shirafuji
Image from Wiki Fandom

Fulminated Mercury becomes an item drop from defeated enemies once the player has visited the Sunken Valley and Ashina Depths locales and is most likely to be obtained when the game has switched from the day to the evening. You’ll want the Demon Bell activated as well. As per any farming scenario in Sekiro, it doesn’t hurt to pop a Mibu Possession Baloon to increase the likelihood of getting rarer item drops. As Fulminated Mercury is an explosive agent used often with guns, it makes sense that the enemies most likely to drop it upon defeat are the members of the Sunken Valley Clan, who prefer guns to blades.

There are three different types of enemies in the Sunken Valley Clan outside the two Snake Eyes mini-bosses. The regular enemies are as follows:

  1. Sunken Valley Clan Member Riflewielder
  2. Sunken Valley Clan Member Scatter-Shot
  3. Sunken Valley Clan Member Cannonwielder

All three of these enemies can be devastating from afar, but other than the Cannonwielder don’t possess much prowess up close and personal. If you’re overwhelmed by them and have the Spirit Umbrella prosthetic in your possession, you can always use that to absorb their damage and even flip some of it back to them in a painful close-range attack. Dodging is effective, and you can also block shots if needed.

Later in the game, when you revisit Ashina Castle and find that all hell has broken loose, the Interior Ministry Red Guard enemies also have the potential to drop Fulminated Mercury upon defeat. Those enemies are as follows:

  1. Red Guard Dual Katana Wielder
  2. Red Guard Flamethrower Wielder*
  3. Red Guard Rifle and Dual Odachi Wielder*
  4. Red Guard Red Hat Guard
  5. Red Guard Dual Katana and Rifle Wielder*

In my experience, the enemies marked with “*” are the most likely to drop Fulminated Mercury, but with the Demon Bell and an optional Possession Baloon in play, they’re all fair game.

Red Guard Rifle Wielder
Image from Wiki Fandom

Combat encounters aside; there are also a few fixed locations that provide Fulminated Mercury in every playthrough. These locations are as follows:

  1. You’ll find an island filled with deadly white monkeys within the Bodhisattva Valley locale. Across the island, you’ll see a rock. Upon checking behind it, you should find the first drop of Fulminated Mercury within a body of contaminated water.
  2. If you make the right choices that allow you to revisit the Hirata Estate memory, you can find two drops of Fulminated Mercury near where you face off against Juzou the Drunkard for the second time.
  3. Later in the game, after the Red Guard has invaded Ashina Castle, you can find a drop of Fulminated Mercury up the main staircase that leads to the castle. Check an area on the right.
  4. Upon defeating the Seven Ashina Spears mini-boss in the Ashina Reservoir after the Red Guard has invaded, you can find a drop of Fulminated Mercury in the area behind him.
  5. Upon revisiting the Ashina Outskirts post Red Guard invasion, you can find a single Fulminated Mercury near where the Ogre spawns at a canon.
  6. You can also find another drop of Fulminated Mercury near where you initially fought the Ogre upon revisiting the Ashina Outskirts post-invasion. Check behind some boxes at the top of the stairs where you two originally crossed blades.

Finding Fulminated Mercury is good, but farming it and having a plentiful supply is even better. Our next section will tell you two of the prime farming spots for this precious resource.

Let Your Harvest Be Bountiful: Where To Farm Fulminated Mercury

Poison Pool
Image from Wiki Fandom

Who’s ready for the fun part? Fulminated Mercury has a few different farming opportunities and are at different parts of the game. One farm occurs approximately during the middle, and another I want to mention occurs towards the end, so there will be a minor spoiler. To begin, we’ll start with the spoiler-free option. Once you visit the Ashina Depths and locate the Poison Pool Sculptors Idol, you’ll find yourself challenged by various gunmen and one of the two Snake Eyes mini-bosses, all while having to grapple hook over a poison-filled swamp. You can spawn here, use a Mibu Possession balloon if you have one, and take the shooters out. More often than not, you’ll find yourself at least one drop of Fulminated Mercury, and if not, the Sculptor’s idol is nearby, and you can rest there and respawn the enemies until you do. This quick and breezy farm also rewards you with some experience to help you level up. However, I used a different method that I found to bear far more plentiful fruit.


Sculptor's Idol
Image from Wiki Fandom

Towards the endgame, you’ll find that the Interior Ministry has invaded Ashina Castle. These guys are no joke and are some of the most challenging enemies you’ll fight in the game. While this entire segment is top-notch for grinding and getting more Sen to purchase Spirit Emblems and other items, it also holds the best Fulminated Mercury farm in the game.

Essentially all you need to do is spawn at the Ashina Castle Gate Sculptors Idol. Once you do, you’ll want to pop a Mibu Possession Baloon immediately. After that, run up the pathway, and you’ll see many Interior Ministry Red Guard soldiers battling against Ashina Castle forces. Run to the combat, use the Golden Vortex once or twice, collect your items, and immediately respawn. You should find at least one upwards of three drops of Fulminated Mercury within your first three spins. Do this for ten or fifteen minutes, and you’ll be stacked with it. While this won’t help you obtain experience, it is cheap, easy, and efficient.

Alternatively, if you unlock it, you can use the Demon Bell at Senpou Temple to help make farming for Fulminated Mercury and other components easier no matter where you are in the game. This handy bell makes foes more challenging and increases your rewards via better item drops, more Sen, and more experience.

Key Points

  • Each Prosthetic Upgrade is different than the previous one, and there are certain times when you might need to switch to a lower rung upgrade to better fit your situation. One isn’t necessarily more helpful than the other. Instead, they all have a time and place.
  • You’ll want to upgrade your prosthetics to give you more flexibility in combat. The bulk of the combat system is reliant on excellently timed parries and swift dodging, but the right Prosthetic in the right place can quickly turn the tide and make mincemeat out of bosses and challenging enemies.
  • While there is no magic gauge in Sekiro, you must manage your prosthetics and special moves (combat arts) by watching your Spirit Emblems. Therefore you’re encouraged to use prosthetics in precise moments with surgical precision.
  • Fulminated Mercury is needed to help upgrade a plurality of prosthetics, and it’s rare to find and in high demand.
  • You cannot get a Platinum Trophy or every Achievement without upgrading every Prosthetic to its maximum potential.



Question: Can’t I Buy Fulminated Mercury from Merchants?

Answer: No. This is a FromSoftware game we’re talking about here. They wouldn’t just hand over one of the most essential components in the game. If you want it (and you will), you must fight or farm for it.

Question: What if I Don’t Use Prosthetics that Require Fulminated Mercury for Upgrades?

Answer: You are either a very skilled Shinobi or a total masochist. While you are welcome to march to the beat of your own drum, you will make the game needlessly more challenging than it needs to be, and the higher-level upgrades that use it, such as the Shinobi Fireworks or Flame Vent, will come in handy towards the later game or while doing various New Game + playthroughs.

Question: Why Should I Upgrade Everything?

Answer: Even if you beat the game without maximizing your upgrades, you’ll find that even early game bosses and mini-bosses become much more powerful in your second playthrough. Moreover, to deny yourself the experimentation with different prosthetics is to deny yourself essential components of the game itself. Sekiro wants you to experiment. It wants you to be quick-witted and fleet-footed. It wants you to pull just the right tool for the battle because, like every FromSoft game, nothing is impossible; You just might need to change your angle.

Prosthetic Arm
Image from Wiki Fandom


Sekiro: Shadows Die Twice is just as much a departure as it complements the existing grind and gameplay dynamics FromSoft has specialized in since they blessed us with Demon Souls all those years ago. For players that prefer a tighter and more narrative-driven game, this is one I highly recommend checking out. I can’t recommend this one enough for people who just beat Elden Ring but still have that Soulsborne itch to scratch. There is nothing quite like Sekiro, and while it is highly challenging, it’s far from impossible. Hopefully, our Fulminated Mercury guide helps you in your journey to restore order to Ashina and unleash Wolf to his full potential. Did you have a particular Fulminated Mercury farming spot that you felt helped you along your way?

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