This is a weapon that burns enemies using a short-ranged flame burst. If you use douse enemies with Oil, you’ll be able to burn them almost instantly. Mini-bosses can be interrupted and stopped on their tracks (giving you the chance to land free hits) if you timed this tool’s use properly.
There are also specific enemies that get scared by the flame burst, like the Chained Ogre which you can stun for a few seconds upon using this tool. This tool has situational usage and short range so you can’t rely on it too often. It’s better to swap it out from your equipment menu once you have better alternatives, and equip it only once you need it.
Living Force is the last skill of the Prosthetic Arts skill tree, that imbues your weapon with the tool's effect. This skill is initially compatible with Flame Vent, temporarily changing your weapon to a flaming one.
Where to find it?
This is one of the earliest shinobi tools you’ll gain access to. First, you have to unlock Hirata Estate. Continue until you reach the Estate Path sculptor’s idol.
From there, you can ignore the enemies and make your way to the first walled yard to the right. You should a smoke billowing nearby. Head towards that direction and grapple to the only branch there. Use this spot to scout the area.
There’s a lot of enemies in this area, including some wolves and archers. You need to clear the area so you can safely pick up the item in the middle of the bonfire. Proceed as you please then once the enemies are clear, go to the bonfire to see several items. The item in the middle of the fire is the Flame Barrel. Bring this to the sculptor to craft the Flame Vent tool.
You’ll access to the prosthetic tool upgrade menu after defeating Gyoubu Oniwa and getting the Mechanical Barrel he drops. Talk to the Sculptor and give him the barrel to unlock the menu.
Similar to skills, there are also upgraded versions of prosthetic tools that will require pre-requisite upgrades before you can unlock them. Each upgrade will require upgrade materials; higher tier upgrades requiring uncommon or rarer materials. Take note that you can still use the older versions of the tools should you wish to.