Fulminated Mercury Sekiro is an important late game upgrade material that players can use to increase their power. Although it's typically obtainable through combat with specific enemies, pioneering players have found a way to collect large amounts of it rather efficiently. Here's how to farm Fulminated Mercury, and what to use it for. Spoilers ahead.
Fulminated Mercury Sekiro: How to Farm it, How to Use it
Fulminated Mercury can be brought to the Sculptor in the Dilapidated Temple to upgrade Prosthetic Tools. Here are the available upgrades:
Tier 5 Loaded Spear
Great Feather Mist Raven
Tier 5 Mist Raven
Purple Fume Spark
Tier 5 Firecracker
Suzaku's Lotus Umbrella
Tier 5 Loaded Umbrella
Tier 6 Sabimaru
Tier 6 Loaded Axe
Lazulite Sacred Flame
Tier 6 Flame Barrel
It can naturally be found at Ashina Outskirts. Killing the Ministry Gunman after being locked out of the area rewards one Fulminated Mercury, as does killing the Gunmen patrolling the area around the Poison Pool idol in Ashina Depths.
To farm Fulminated Mercury, wait until you've obtained the Golden Vortex Tool and the Ministry begins to attack you at the Ashina Castle Idol. Go to the Idol and use a Mibu Possession Balloon to up the item drop rate from enemies.
Run up at the stairs ahead of the idol to the enemies at the top, then use the Golden Vortex to look all the nearby enemies. Head back to the Idol, rest to reset the area, and repeat until you're satisfied with your Fulminated Mercury inventory.
Photo courtesy of From Software/Activision