This is an unofficial fan project based on the Mistborn series of books written by Brandon Sanderson.

In this project, I've adapted Feruchemy (from the Mistborn series of books) into a survival and multiplayer friendly Minecraft datapack.

What is Feruchemy? (Spoiler-Free Summary)

In the world of Mistborn, certain people (called Feruchemists) can store attributes of themselves in pieces of metal. There are a variety of metals that can be used, and each one stores a different attribute. Later, the Feruchemist can draw upon the stored attribute. A piece of metal that a Feruchemist has stored an attribute in is called a "metalmind," but can also be referred to as the specific type of metal (i.e. coppermind or pewtermind).

One example is the metal pewter, which can be used to store strength. A Feruchemist can store strength into a piece of pewter, becoming noticeably weaker until they stop storing. Then, they could tap that strength out of the metalmind, becoming noticeably stronger. They can even vary the rate at which they store or tap, making themselves just a little bit weaker over a long period of time so that they can become significantly stronger for a few minutes.

Datapack Contents

Overview

In the datapack, instead of being able to use any piece of metal, rare metallic bracers that can be found in loot chests are required to use Feruchemy. Additionally, these artifacts aren't tied to a single person, but can be shared amongst players, and only one can be used (per player) at a time.


Once a metalmind has been acquired, it can be placed in the players offhand slot to use. While wearing it, crouch and right-click to start storing, or right-click without crouching to start tapping. Each metalmind has two different speeds for storing and tapping, with different effects for each. The damage bar on the item will indicate how full the metalmind is.

The Metalminds

Metal	Description	Location	Store x1 Effect	Store x2 Effect	Tap x1 Effect	Tap x2 Effect
Pewter	Strength	Simple Dungeon	Weakness II	Weakness IV Mining Fatigue	Strength II	Strength IV Haste
Steel	Speed	Simple Dungeon	Slowness III	Slowness VI	Speed III	Speed VI
Tin	Senses	Pillager Outpost	Darkness	Darkness Blindness	Night Vision	N/A
Gold	Health	Desert Pyramid	Poison II	Poison IV	Regeneration I*	Regeneration II*
Bendalloy	Energy	Buried Treasure	Hunger (33)	Hunger (65)	Saturation (33)*	Saturation (65)*
Iron	Weight	End City	Jump Boost II	Jump Boost IV Slow Falling II	Jump Boost 254 (.75 block max)	Jump Boost 255 (.125 block max)
Copper	Memories	Stronghold Library**	Drains XP	Drains XP (faster)	Gives XP	Gives XP (faster)
Nicrosil	Investiture (Magic)	Ancient City	Copy enchantment from mainhand to metalmind	N/A	Copy enchantment from metalmind to mainhand	N/A

* Effect only active when not at max health/hunger
** Guaranteed loot

Advancements

There are advancements for finding each of the metalminds the first time, as well as some challenges to complete once you have them.
There are a total of 16 advancements, including:
1 root advancement - obtained when any metalmind is found
8 metalmind acquired advancements - one for each type of metalmind
6 metalmind challenges - goal revealed when the appropriate metalmind is discovered
1 hidden advancement - awarded to those who try to cheat the system :P

Commands

Just want to play around for a bit with the metalminds but don't want to dig too deep into the code? Here are some commands to get you started:

Give metalmind (replace "copper" with desired metalmind):
/loot give @s loot feruchemy:copper_metalmind
Set durability (with metalmind in offhand, set score anywhere from 0 to 100):/scoreboard players set @s feru_durability 50
/item modify entity @s weapon.offhand feruchemy:set_durability

Resource Pack

For the best experience, please use the included resource pack! Otherwise you're just going to be running around with a fungus-on-a-stick everywhere you go...

Support

If you have any questions, post them here or on my Discord server: https://discord.gg/Vr9vfP6EqH